#1/4 wave professional gp antenna | Explore Tumblr posts and blogs

certainheartrunaway · 4 years ago

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Current Ham Radio News

How to Connect a Modern Radio to a Legacy Tube Amp

Antenna

PVC Antenna Launcher by K8BLO

January 05, 2016

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PVC Antenna Launcher – Download: Read more

An Intro and Antennas – Nuts and Volts Magazine

February 04, 2015

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An Intro and Antennas – Nuts and Volts Magazine by H. Ward Silver Read Full Article: Read more

Q52 Relay-switched 20-17-15-12-10 meter Yagi

April 30, 2015

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See Q52 20 17 15 12 10 5-band Remote Switched 2el Yagi Coverage band in 2 segments whole band whole band whole band >1.1MH... Read more

LOOP RX 160/80/40

September 23, 2015

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LOOP RX 160/80/40 Technical specifications 160m Gain – 29dbi 80m Gain –18dbi 40m Gain- 10dbi Weight 7Kg Price 420 Eu... Read more

Maldol HVU-8 Vertical Base Station Antennas HVU-8

October 21, 2015

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Operational Bands 80 meters 40 meters 20 meters 15 meters 10 meters 6 meters 2 meters 70 centimeters Maldol HVU-8 Vertical Base Station Antenna... Read more

Review

Grounding, Bonding, Earthing, Shielding and Protecting with W6LG

May 25, 2019

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Part 1 of 2. Jim recommends in detail how he believes grounding should be installed in the typical Ham Radio Statio Read more

Unboxing the AnyTone AT-D578UV III Pro DMR/FM Mobile Radio

March 26, 2020

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AnyTone AT-D578UVIIIPRO Tri-Band Amateur DMR Mobile Radio with Bluetooth, GPS and BridgeCom University Want the latest and greatest DMR radio? We ar... Read more

SPE 2K-FA Amplifier – ARRL Review

September 11, 2016

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2 KW Solid State Fully Automatic Linear Amplifier The smallest in its class. Built-in Power supply and Automatic Antenna Tuner. Dimension: L 38, H 18.... Read more

Anytone AT-D578UV Pro DMR Mobile Radio | First Look!

December 31, 2019

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DV4home – Basic setup and menu navigation

September 16, 2016

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This is the part 1 video of the DV4home, showing the basic setup and menu navigation. Read more

Equipment

Palstar SP30H

October 09, 2014

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The Palstar SP30H ultimate communications speaker is a custom engineered speaker designed to match the sonic characteristics of the human voice. The... Read more

Elecraft KX3 Transceiver

January 06, 2015

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Elecraft KX3 Transceiver Ultra-Compact Home/Portable/Mobile Station The revolutionary Elecraft KX3 puts the world in the palm of your hand! Despite it... Read more

Yaesu Luxury dual element microphone M-100 announced!

May 17, 2017

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“Amateur radio transmitting voices on radio waves, direct more faithfully the direct sound more faithfully … …” Following the... Read more

NooElec NESDR Nano 2 – 25MHz-1750MHz

December 03, 2015

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Product Description Brand new re-design! The NESDR Nano 2 are custom-made by NooElec for SDR applications, though they will still function as qualit... Read more

QCX-mini is coming soon!

November 11, 2020

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QCX-mini is a response to quite a few comments on the new QCX+ kit, from people who want to take it out portable for SOTA operations and other po... Read more

News

ARRL CEO David Minster, NA2AA, to Keynote QSO Today Virtual Ham Expo

February 24, 2021

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ARRL CEO David Minster, NA2AA, will keynote the QSO Today Virtual Ham Expo March 13 – 14 weekend. Minster’s talk — part of an 80+ speak... Read more

23cm band in the spotlight with regulators

February 24, 2021

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During the week 15 – 19 February, the preparatory work for WRC-23 agenda item 9.1b continued in ITU‑R Working Party 4C (WP4C)... Read more

How to Connect a Modern Radio to a Legacy Tube Amp

February 24, 2021

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How to Connect a Modern Radio to a Legacy Tube Amp Read more

A Filament Slingshots Towards Earth | Solar Storm Forecast 02.22.2021

February 23, 2021

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https://www.youtube.com/watch?v=bNxuOtBMN2s Read more

German radio hams tackling RF noise pollution

February 21, 2021

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DARC reports 35 Electrical Noise Area Monitoring Systems (ENAMS) have been delivered and another 20 locations are sought as part of the effort to moni... Read more

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February 24, 2021 at 10:09AM

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Current ham radio news

Many thanks to SWLing Post contributor, Dave (K4SV), who shares the following video: Click here to view on YouTube.

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February 24, 2021 at 10:09AM

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Current ham radio news

During the week 15 – 19 February, the preparatory work for WRC-23 agenda item 9.1b continued in ITU‑R Working Party 4C (WP4C). The WRC agenda item has initiated technical studies on coexistence between the radio navigation satellite service (RNSS) and the amateur services in the 23cm band. As usual, the IARU participated in the meeting and delivered key information on amateur activities in this important microwave band. This information is vital to ensure the amateur services are realistically represented in the studies as they move forward.

It remains vital that national amateur communities present their views on the importance of this band to their national regulators in a consolidated and consistent manner.

To assist with this the IARU-R1 is developing supporting material that member societies can refer to when addressing the topic with their national regulator.

The work on this topic will continue throughout the year and beyond both in ITU‑R and in the regional telecommunications organisations and the IARU is committed to ensure every organisation understands the amateur position on this important microwave band.

ITU‑R WP4C Meeting Report here

Antenna

Ensure Better UHF Coaxial Feed Lines

June 09, 2016

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By DX Engineering’s Blog HF users really don’t have many coax issues. As long as power levels aren’t breached, just about any feed line will work with... Read more

A 630-10 meter experimental antenna. Part 1, the plan.

March 10, 2020

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RQ-84 – The classic “Quad” full-size has ten elements for 10m, eight – 15 m, six – 20 m, and four full-size elements on 40m band

August 18, 2015

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RQ-84 – the classic “Quad” full-size has ten elements for 10m, eight – 15 m, six – 20 m, and four full-size elements on... Read more

Antenna 1/2-wave, 5-Band HF Cobweb Antenna – MFJ-1835 Time Lapse Video

November 16, 2016

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1/2-wave, 5-Band HF Cobweb Antenna Restricted space spoiling your operating fun? MFJ-1835 puts your call back on the map! This fiveband (20, 17, 15, 1... Read more

The New Hy-Gain BOLP-1013 Band Optimised Log Periodic Array by G0KSC

January 26, 2017

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This revolutionary antenna consists of 6 trapless monoband logs on a single 30’ boom and 13 full size elements. Computer optimization gives full monob... Read more

Review

Building The QRP-Labs QCX 50W CW HF Amplifier Kit

January 19, 2020

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Icom IC-7300 Morse Code and Display Overview [ Video ]

February 02, 2016

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Icom revealed their first Software Defined Radio (SDR) HF transceiver, the IC-7300, on Saturday, August 22nd 2015, at the Tokyo Ham Fair... Read more

Jim W6LG Talks About Grounding, Bonding, Earthing, Shielding and Protecting

March 02, 2019

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What are grounding, bonding, earthing, shielding and protecting in the amateur radio station? This is Part 1 of a series of videos. Should you run a g... Read more

Eliminate Interference with the MFJ-1026 Noise Canceller

January 15, 2020

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Wipe out noise and interference before it gets into your receiver with a 60 dB null! Eliminate all types of noise — severe power line noise from... Read more

Ham radio & 3D printing – A very portable table stand for the Icom IC-705.

November 22, 2020

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Ham radio & 3D printing – A very portable table stand for the Icom IC-705. Read more

Equipment

ALPHA RF Systems – Hamvention

June 09, 2019

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ES-4 Radio / Antenna Selector Switch between 3 radios and 5 antennas

July 06, 2018

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ES-4 COMES AS A CONTROL UNIT AND A BASE (SWITCHING) UNIT THE BASE UNIT RECEIVES 12V POWER AND HAS ALL THE HEAVY COAXIAL CABLES CONNECTED TO IT. THER... Read more

Elecraft K4 – Price list!

May 17, 2019

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Elecraft K4 STANDARD FEATURES Size: 4.5”H x 13.5”W, 10” D Weight: Approx. 10 lbs Supply Voltage: 12-15 VDC Current: ~2 A RX, ~18-23 A TX Frequenc... Read more

Icom IC-9100 Review [ Video ]

April 10, 2015

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George Thomas, W5JDX, of Ham Nation and AmateurLogic.tv provides an in depth review of the Icom IC-9100 Read more

50 Ohm PROFESSIONAL COAXIAL CABLES

May 09, 2015

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COAXIAL CABLES Cables for transmission and reception for both professional and amateur 50 Ohms. The low loss and low SWR factor (SRL) make them unique... Read more

News

ARRL CEO David Minster, NA2AA, to Keynote QSO Today Virtual Ham Expo

February 24, 2021

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ARRL CEO David Minster, NA2AA, will keynote the QSO Today Virtual Ham Expo March 13 – 14 weekend. Minster’s talk — part of an 80+ speak... Read more

23cm band in the spotlight with regulators

February 24, 2021

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During the week 15 – 19 February, the preparatory work for WRC-23 agenda item 9.1b continued in ITU‑R Working Party 4C (WP4C)... Read more

How to Connect a Modern Radio to a Legacy Tube Amp

February 24, 2021

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How to Connect a Modern Radio to a Legacy Tube Amp Read more

A Filament Slingshots Towards Earth | Solar Storm Forecast 02.22.2021

February 23, 2021

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https://www.youtube.com/watch?v=bNxuOtBMN2s Read more

German radio hams tackling RF noise pollution

February 21, 2021

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DARC reports 35 Electrical Noise Area Monitoring Systems (ENAMS) have been delivered and another 20 locations are sought as part of the effort to moni... Read more

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February 24, 2021 at 10:09AM

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Current ham radio news

ARRL CEO David Minster, NA2AA, will keynote the QSO Today Virtual Ham Expo March 13 – 14 weekend. Minster’s talk — part of an 80+ speaker lineup — will begin at 2000 UTC (3 PM EST) on March 13. His appearance will highlight ARRL’s featured role at the Expo, which also will include “Ask The ARRL Lab.” ARRL is a QSO Today Virtual Ham Expo Partner.

Minster, who assumed the ARRL Headquarters leadership position last September, has launched major projects and assembled teams to foster innovation and individual skill development in radio technology and communications. In his keynote, Minster will share his enthusiasm for advancing amateur radio and highlight current ARRL initiatives to engage and inspire the current generation of hams. His presentation topics will include:

ARRL’s digital transformation, which promises to bring new value to ARRL members. An all-in digital approach will improve the way members access and engage with content, programs, and systems.

The ARRL Learning Center, a hub for members to discover the many facets of amateur radio and develop practical knowledge and skills.

Increasing video content, opening opportunities for amateur radio content creators and member-volunteers to learn, stay informed, and keep connected.

Improving training and tools to engage radio clubs, emergency communication volunteers, and students.

The ARRL Expo booth will feature “Ask the ARRL Lab,” where Lab staffers will answer questions live. Attendees can come into the booth lounge (featuring the Expo’s latest virtual meet-up and video technology), sit down at a virtual table, and ask ARRL Lab technical wizards for tips about projects or suggestions to address various station installations and problems. Attendees can also learn about Product Review equipment testing by the Lab, see a presentation on how the Lab can help hams with RFI problems, and tour W1AW — the Hiram Percy Maxim Memorial Station — virtually. ARRL booth staff will also point attendees to helpful resources from across membership benefits, services, and programs.

Representing the ARRL Lab will be Lab Manager Ed Hare, W1RFI; Test Engineer Bob Allison, WB1GCM; Senior Laboratory Engineer Zack Lau, W1VT; RFI Engineer Paul Cianciolo, W1VLF, and W1AW Station Manager Joe Carcia, NJ1Q. Between all of them, they have over 100 years of experience at ARRL Headquarters,

QSO Today Virtual Ham Expo Chairman Eric Guth, 4Z1UG, also announced four live group kit-building workshops. Workshop instructors will guide participants through building a variety of kits, which will be available for purchase and delivered prior to the Expo so attendees can build them at home. Attendees unable to participate during the live sessions can order and build kits by watching the workshop videos during the on-demand period that follows the Expo through April 12.

Workshop kits prices range from $15 to $30. Early-bird discount tickets and links to purchase kits can be found at the QSO Today Expo website. These workshops will include:

Building the NS-40 QRP Transmitter, a 14-component, 5 W transmitter for 7.030 MHz (with instructors David Cripe, NM0S, and Virginia Smith, NV5F).

The Learn-to-Solder Workshop will introduce the basic tools and techniques of building electronic kits. Participants will build a 20-meter transmitter kit (with instructors Rex Harper, W1REX, and Stephen Houser, N1SH).

Building the Cric-Key, a simple CW keyer with paddle, suitable for home and field use (with instructor Joe Eisenberg, K0NEB).

The Mini-Sudden Receiver, a pocket-and-mint-tin friendly direct-conversion 20-meter receiver (with instructors Rex Harper, W1REX, and Stephen Houser, N1SH).

SOURCE:ARRL

Antenna

4 element 70Mhz 4m Yagi LFA-R

October 06, 2015

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Description A 4 element 70MHz High Gain Yagi – The unique LFA-R from InnovAntennas! The LFA-R from InnovAntennas does away with the traditional... Read more

New! Vertical Loop Yagi ( 6 to 40m ) – Ultra Beam

March 05, 2015

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Vertical Loop Yagi See More : Link Read more

80m or 160m Reduced Half Sloper Antenna by W8AMZ

January 28, 2015

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160m Reduced ½ Sloper Do You Have Limited Space? Do You Dream Of Operating 160m? NO PROBLEM! Do you... Read more

Alex PY1AHD demonstrates how easy and FAST it is to set up his AlexLoop

May 10, 2015

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Alex, PY1AHD, demonstrates how easy and FAST it is to set up his AlexLoop Read more

2-Element- DK7ZB – Quad Antenna for 5 Bands

January 08, 2015

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“The Quad Antenna uses a single, central-fed frame with a feeder-line. Therefore you must use an ATU for operating this antenna. Excellent woul... Read more

Review

SunSDR MB1 by Expert Electronics – Review and walk through

May 03, 2018

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Here is a quick tour of the SunSDR MB1 by Expert Electronics. It’s an operator’s point of view and a simple walk through this great HF rad... Read more

IC-7610 Technical Report (Volume 1)

February 27, 2018

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Icom Inc. have published a technical report on the IC-7610 HF/50MHz SDR Transceiver. In this report you will find detailed information about its featu... Read more

W6LG Talks To David G4AKC Who Is Pedestrian Mobile In The UK

November 26, 2018

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“Jim W6LG talks to G4AKC, David Starkie in England. David is Pedestrian Mobile running about 100 watts to a quarter wavelength long vertical mob... Read more

Amateur Radio Band Plan [ VIDEO ]

December 02, 2019

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Retevis RT6 Dual Band Analog HT Unboxing

July 14, 2020

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Retevis RT6 Review of the Dual Band Analog HT. Unboxing the radio and taking a look at the menus. Read more

Equipment

SO-239 antenna ballmount for mobile Station

November 25, 2014

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SO-239 connection on top of the ball mount for the antenna and for the PL-259 connection on the inside of the vehicle. The plates are 3 inches in... Read more

Inrad HF Triplexer

December 11, 2014

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The Inrad HF Triplexer is the perfect solution for adding more fun and points at Field Day or WRTC: Three stations may share one 10M/15M/20M tribander... Read more

ICOM IC-R8600 [ VIDEO ] – Hands on !

April 04, 2017

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ICOM IC-R8600 Features Ultra-wide frequency coverage (10kHz-3GHz) with RSSI (Received Signal Strength Indication) function Fast moving, real-time spec... Read more

XPA125B 125W Solid State Linear Amplifier

July 05, 2018

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Xiegu XPA125B is a small and lightweight 125 watt HF and 50 MHz solid state linear power amplifier perfect for your QRP radio or low power SDR... Read more

RPi3 image for SDRplay

November 19, 2018

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SDRplay “This release (V0.4) is a complete image for the Raspberry Pi 3 with a range of pre-built applications for SDRplay devices. Please note... Read more

News

ARRL CEO David Minster, NA2AA, to Keynote QSO Today Virtual Ham Expo

February 24, 2021

No comments

ARRL CEO David Minster, NA2AA, will keynote the QSO Today Virtual Ham Expo March 13 – 14 weekend. Minster’s talk — part of an 80+ speak... Read more

23cm band in the spotlight with regulators

February 24, 2021

No comments

During the week 15 – 19 February, the preparatory work for WRC-23 agenda item 9.1b continued in ITU‑R Working Party 4C (WP4C)... Read more

How to Connect a Modern Radio to a Legacy Tube Amp

February 24, 2021

No comments

How to Connect a Modern Radio to a Legacy Tube Amp Read more

A Filament Slingshots Towards Earth | Solar Storm Forecast 02.22.2021

February 23, 2021

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https://www.youtube.com/watch?v=bNxuOtBMN2s Read more

German radio hams tackling RF noise pollution

February 21, 2021

No comments

DARC reports 35 Electrical Noise Area Monitoring Systems (ENAMS) have been delivered and another 20 locations are sought as part of the effort to moni... Read more

The post ARRL CEO David Minster, NA2AA, to Keynote QSO Today Virtual Ham Expo appeared first on QRZ NOW - Ham Radio News.

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February 24, 2021 at 10:09AM

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Current ham radio news

Many thanks to SWLing Post contributor, Kevin, who writes: I often see people on the side of the road at intersections holding signs, “homeless, can you help”, that sort of thing. Like a lot of people I used to ignore them. A few years ago I decided that I wanted to help so I looked […]

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February 24, 2021 at 10:09AM

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Current ham radio news

We have never truly been happy with any of the header images since the new website was launched last year. Every few weeks we’d change them and again we have changed them today. Finally, we have settled upon an idea and perhaps the reader may like to help – especially when it comes to the […]

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DX-World Header Images

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February 24, 2021 at 05:09PM

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Current ham radio news

Rolf DL7VEE reports the following: There is no hope for a CE0X operation at this time; either from San Felix or San Ambrosio due to restrictions from the military. Dino, CE3PG President of Radio Club de Chile says he talked to Chilean Army officers who said no way – even regardless of Covid situation. He […]

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San Felix future activity unlikely

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February 24, 2021 at 05:09PM

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Current ham radio news

ARRL -

ARRL Amateur Radio Emergency Service (ARES®) and American Red Cross volunteers joined forces in Texas under the ARRL/Red Cross memorandum of understanding in responding to the situation resulting from unseasonably frigid weather. Kevin McCoy, KF5FUZ, said the Red Cross formally requested an ARES activation in Texas to address the effects of the natural disaster, which included a lack of drinkin...

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February 24, 2021 at 05:09PM

via RSS Feed http://www.arrl.org/news/view/ares-and-red-cross-cooperate-to-assist-storm-affected-residents-in-texas

Current ham radio news

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February 24, 2021 at 05:09PM

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Current ham radio news

ARRL -

The amateur radio communications team of the Florida Baptist Disaster Relief has created a multi-site radio communications exercise dubbed “Whirlwind Boom,” designed to bring together volunteers and local agencies across northern Florida and throughout the southeastern US. The 2-hour drill is set for Friday, March 19. Invitations have gone out to Amateur Radio Emergency Service (ARES®) groups, ...

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February 24, 2021 at 08:09PM

via RSS Feed http://www.arrl.org/news/view/whirlwind-boom-emergency-communications-exercise-set-in-northern-florida

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February 24, 2021 at 08:09PM

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littlecat0520 · 3 years ago

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Touch Screen Technology Application and Classification

With the development of computer technology, the input method of the computer has gone from the original paper tape input to the keyboard input, to the mouse input, and then to the touch input, which has gone through four stages. This process is a process from professional to popularization. Touch screen technology allows more people to use the computer.

A touch screen is an interactive input device. The user only needs to touch a certain position on the screen with a finger or a light pen to control the operation of the computer. Therefore, the touch screen technology has the characteristics of simple operation and flexible use.

Touch screen is also called touch panel. When the graphic buttons on the screen are touched, the haptic feedback system on the screen can drive various linking devices according to a pre-programmed program, which can be used to replace the mechanical button panel and create a dynamic audio-visual effect by the LCD. Simply put, it is an inductive display device that can be connected to input signals such as contacts.

The application scenarios and terminals of touch screens are very extensive, and they can be divided into 7 categories from the perspective of scene types:

Type 1: Portable Equipment

Including Mobile phone, Pocket PC, E-book, Web Pad, Translator, Tablet PC, etc.

Type 2: Public Information Equipment

Including ATM, Public Inquiry Machine (Kiosk), Ticket Vending Machine, Digital Photo Printing System, etc.

Type 3: Communication Equipment

Including Video Phone, SmartPhone, Internet TV, Set-top box, GPS, etc.

Type 4: Office Automation Equipment

Including Copier, Punch Card Machine, Word Processor, Electronic Touch Whiteboard, etc.

Type 5: Information Collection Equipment

Including POI, POS Information Inquiry Machine, etc.

Type 6: Information Appliances

Including Refrigerator, Microwave, Coffee Maker, Washing Machine, LCD TV, etc.

Type 7: Entertainment Devices

Including Gaming Machine, Gambling Machine, Slot machine, Roulette machine, etc.

According to the type of sensor, touch screens are roughly divided into five types: infrared, resistive, surface acoustic wave(SAW), capacitive touch screens, and electromagnetic touch screens.

Infrared technology touch screens are inexpensive, but the outer frame is fragile, which is prone to light interference and distortion in curved surfaces. The design of capacitive technology touch screens is reasonable, but it is difficult to solve the problem of image distortion. The positioning of resistive technology touch screens is accurate, but its The price is quite high, and it is afraid of scratching; the surface acoustic wave touch screen solves the various defects of the previous touch screen, and it is not easy to be damaged. It is suitable for various occasions. The disadvantage is that if there are water droplets and dust on the screen surface, the touch screen will become dull It doesn't even work; electromagnetic technology touch requires a professional stylus, which is inconvenient to use.

1.Infrared touch screen

The principle of the infrared touch screen is very simple, just add the frame frame of the light spot distance on the display, without adding a coating or connecting the controller to the surface of the screen. Infrared emitting tubes and receiving tubes are arranged on the four sides of the frame from the light spot to form an infrared network on the screen surface. When the user touches a certain point on the screen with his finger, the two infrared rays passing through the position are blocked, and the computer can immediately calculate the position of the touched point. Because the infrared touch screen is not affected by current, voltage and static electricity, it is suitable for some harsh environmental conditions. Its main advantages are low cost, easy installation, no need for cards or any other controllers, and it can be used on computers of all grades. However, since the frame is only added to the ordinary screen, the infrared emitting tube and the receiving tube around the frame are easily damaged during use.

2.Resistive touch screen

The surface touched by the finger is a hard coating to protect the underlying PET layer. The PET layer is a thin elastic PET film that bends downward when the surface is touched, and allows the two underlying ITO coatings to contact each other and connect the circuit at that point. Between the two ITO layers is a separation fulcrum about one thousandth of an inch thick that separates the two layers. At the bottom is a transparent hard bottom layer to support the above structure, usually glass or plastic.

3.Surface Acoustic Wave(SAW) touch screen

A surface acoustic wave is a mechanical wave that propagates along the surface of a medium. The touch screen is composed of a touch screen, a sound wave generator, a reflector and a sound wave receiver. The sound wave generator can send a high frequency sound wave across the surface of the screen. When a finger touches the screen, the sound wave on the contact point is blocked Determine the coordinate position. The surface acoustic wave touch screen is not affected by environmental factors such as temperature and humidity. It has extremely high resolution, excellent scratch resistance, and long life (50 million times without failure); high light transmittance (92%), which can maintain clear and translucent Image quality; no drift, only need to be corrected once during installation; there is a third axis (ie pressure axis) response, which is most suitable for use in public places.

4.Electromagnetic touch screen

The basic principle of the electromagnetic induction touch screen is to judge by the magnetic field generated by the sensor under the panel during the operation of the electromagnetic pen. The electromagnetic pen is the signal transmitter, and the antenna board is the signal receiver. When a change occurs, the position point is defined by the operation.

5.Capacitive touch screen

Capacitive touch screens are divided into surface capacitive touch screens and projected capacitive touch screens.

(1) Surface Capacitive Technology:

The surface capacitive touch screen uses only a single layer of ITO, and long and narrow electrodes are plated on all four sides of the touch screen to form a low-voltage AC electric field within the conductor. When a finger touches the screen surface, a coupling capacitance is formed between the finger and the conductor layer, and a certain amount of charge is transferred to the human body. In order to recover these charge losses, the charge is replenished from the four corners of the screen, and the amount of charge replenished in all directions is proportional to the distance of the touch point, from which we can calculate the position of the touch point.

(2) Projected Capacitive Technology：

Compared with surface capacitive touch screens, projected capacitive touch screens can penetrate a thicker cover layer and do not require correction. Inductive capacitive etching of different ITO modules on two layers of ITO coating requires consideration of factors such as the total impedance of the module, the impedance of the connecting line between the modules, and the parasitic capacitance generated at the intersection of the two layers of ITO modules.

Which of the five touch screens do you like best? And which one is the best choice?Please follow our next article to learn more!

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snehapatnesblog-blog · 6 years ago

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Global Mobile Phone Antenna Market 2018 Growth Rate by Players: Amphenol, Pulse, Molex, Skycross, Galtronics, Sunway, Speed

Market Research Store Exposed a new deep Industry research report focuses on Mobile Phone Antenna Market, delivers detailed analysis of market and future prospects of Mobile Phone Antenna market. The critical and significant data in the study makes the research a very important tool for experts, analysts and managers to get ready-to-access analysis by the industry professionals. The Mobile Phone Antenna Market report provides the complete analysis of Mobile Phone Antenna Market Size Data and development forecast from 2018-2025.

This reports also include complete information of main Manufacturers/Suppliers of Mobile Phone Antenna around the world and market share by various regions, with the company and product introduction and their position in the Mobile Phone Antenna market.This report also includes the cost and profit status of Mobile Phone Antenna and marketing status, Market growth drivers and challenges in this Market.

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Top Companies in Worldwide Mobile Phone Antenna Market are as follows:- Amphenol, Pulse, Molex, Skycross, Galtronics, Sunway, Speed, JESONcom, Auden, Deman, Ethertronics, Sky-wave, 3gtx, Southstar

The leading competitors among the global Mobile Phone Antenna market are applying various techniques for creating an entry further as developing within the Mobile Phone Antenna market. On a worldwide basis, the count of recognized firms is elevating and therefore it is necessary for each market company to urge an ardent edge on others. The first techniques accepted by the well- known firms for grapple among the Mobile Phone Antenna market embrace melioration of recent product, partnerships, mergers, agreements, and acquisition.

REGIONAL MARKET PERSPECTIVE in :- United States, Europe, China, Japan, India and Southeast Asia.

If you have any customized requirement regarding to Mobile Phone Antenna, we will be happy to include this to enrich the final study and We will offer Competitors shares, Regional Analysis, Product Analysis as per your choice also.

The global Mobile Phone Antenna market report shed light on the latest technological developments, upcoming business opportunities, market restraining factors, threats to offer a perfect acumen for an in-depth market study. It also deals with the region-wise industrial environment, regulatory structure, competitive landscape, raw material resources that might influence Mobile Phone Antenna industry.

Most Applied Mobile Phone Antenna Market in World Industry includes:- Main Antenna, Bluetooth Antenna, Wifi Antenna, GPS Antenna, NFC Antenna, Others

Global Mobile Phone Antenna Market By Product includes:- PIFA(Planar Inverted F Antenna), Internal Planar Monopole, Internal PCB & FPC, LDS(Laser Direct Structuring)

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There are 15 Chapters to display the Global Mobile Phone Antenna market:-

Chapter 1: Definition, Specifications and Classification of Mobile Phone Antenna, Applications of Mobile Phone Antenna, Market Segment by Regions

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Chapter 3: Technical Data and Manufacturing Plants Analysis of Mobile Phone Antenna, Capacity and Commercial Production Date, Manufacturing Plants Distribution, R&D Status and Technology Source, Raw Materials Sources Analysis

Chapter 4: Overall Market Analysis, Capacity Analysis (Company Segment), Sales Analysis (Company Segment), Sales Price Analysis (Company Segment)

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Chapter 7 and 8: Mobile Phone Antenna Segment Market Analysis (by Application) Major Manufacturers Analysis of Mobile Phone Antenna

Chapter 9: Market Trend Analysis, Regional Market Trend, Market Trend by Product Type

Chapter 10: Regional Marketing Type Analysis, International Trade Type Analysis, Supply Chain Analysis

Chapter 11: Consumers Analysis of Global Mobile Phone Antenna

Chapter 12: Mobile Phone Antenna Research Findings and Conclusion, Appendix, methodology and data source;

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#Mobile Phone Antenna Market Growth Mobile Phone Antenna Market Analysis

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xiaoquebanxiaoqueban · 4 years ago

Text

15 minutes to explain how to add solid state hardware to the 15 inch MacBook Pro

directory

1) Uber accident cause analysis

2) automatic driving first day - Safety

3) automatic driving vehicle hardware system

4) automatic driving vehicle sensor sensor

5) automatic driving vehicle sensor

6) automatic driving calculation unit

7) automatic Driving by wire system

< 8) Apollo hardware development platform

Original: Apollo developer community? A week ago

last week, Apollo introduced the basic situation of Baidu Apollo open platform. In this issue, a Bojun will introduce the Apollo hardware development platform.

If you don't say much, you are welcome to enter the fifth advanced course.

The accident happened on the night of March 18, 2018, when a Uber car in driverless test collided with a pedestrian in Tempe, Arizona. The pedestrian was sent to hospital and later declared invalid.

According to the preliminary investigation results, Uber vehicle was in the state of automatic driving when it hit the pedestrian, which is the first case in history that the automatic driving vehicle injured the pedestrian on the open road. This incident sounded the alarm about safety for driverless.

Issued by the U.S. highway Commission on June 22, 2018Accident report:

in the first 6 seconds of the accident, the sensors of the system have found pedestrians; in the first 1 second of the accident, the emergency brake AEB of the original car has been started, but the car has not implemented the brake, because when Uber refits Volvo CX90, the brake system of the original car is cut off, and the subsequent refitted computer will send control instructions to brake.

the system does not have a fully closed-loop state (main cause);

the driver lowers his head to play with his mobile phone, and the system does not give a warning after detecting a pedestrian;

automatic driving and infrastructure are related, and the lack of illumination on the road in the four seconds before the accident results in no pedestrian to be seen from the photos.

There have been other traffic problems before

Uber, such as vehicle scratch, direct rollover, etc.

The reason is that the vehicle sensor (velodyne 64 line) installed later by Uber is heavier, and the SUV center point is higher. After the sensor is installed, the center of gravity moves up, and it is easy to roll when turning a sharp corner.

From the perspective of the R & D process of automatic driving, it can be roughly divided into the following four steps:

software in the loop software in the loop is based on Simulation and simulation software simulation, similar to racing games. That is to simulate the real road environment such as light, weather and other natural environment in the software system. After the development of the automatic driving code, the developer can run it in the simulation system to test whether the goal can be achieved.

Hardware in the loop hardware in the loop is based on the necessaryHardware platform. After the first step of software simulation, all the simulation results, sensors and computing units are assembled and tested in the hardware environment.

Vehicle in loop vehicle in loop is based on vehicle execution. The third step is to test the functions developed by developers in a closed environment. There will be no interference of traffic flow in the closed environment.

Driver in the loop driver in the loop is based on the actual road. After the third step is successful, the driver in the loop is mainly to study the interaction between people, vehicle, road and traffic. It not only tests the program code of automatic driving, but also obtains the judgment of professional drivers.

The above four steps are the whole process of automatic driving R & D. according to the above process R & D can ensure sufficient safety of automatic driving.

Automatic driving is divided into three systems: perception, decision-making and control. Each system has corresponding hardware system. ?

perception system is divided into three parts: vehicle movement, environment perception and driver monitoring.

Vehicle motion is mainly divided into inertial navigation, speed sensor, angle sensor and global positioning system.

Environmental perception mainly includes lidar, ultrasonic, camera, millimeter wave radar and v2x.

Driver monitoring is mainly divided into camera and bioelectric sensor.

The decision system is divided into three parts: calculation unit, T-box and black box.

In the computing unit is the algorithm of autopilot perception decision control. Current autoDriving with X86 structure of the server or industrial computer.

T-box, or telematics box, is the communication gateway of the Internet of vehicles. It is connected to the Internet and connected to the CAN bus. For example, the door opening and closing commands sent by the app on the mobile phone are controlled by sending the operation commands to the CAN bus through the T-box gateway.

The black box is used to record all information and status in the process of unmanned driving.

The control system is divided into vehicle control and warning system.

Vehicle control mainly includes braking, steering, engine and gearbox. Warning system is mainly divided into sound, image and vibration?.

The above is the framework of the whole autopilot hardware system.

introduces the sensor category of automatic driving vehicle.

The camera is mainly used for lane line, traffic sign, traffic light, vehicle and pedestrian detection. It has the advantages of comprehensive detection information and low price, but its performance is greatly affected by weather.

The camera is mainly composed of lens, lens module, filter, CMOS / CCD, ISP and data transmission. The cameras are divided into monocular and binocular.

The basic working principle of the camera: light is focused on the sensor of the CMOS behind through the lens and filter in front of the camera.

the sensor will expose the light signal and convert it into an electrical signal, then convert it into a standard RGB or YUV data grid through the ISP image processor, and finally transmit it to the back-end computerLine processing.

The core principle of lidar is TOF (time of flight), that is, after a beam of light hits an obstacle, the light will generate an echo, and receive and calculate the light turn back distance on APD.

According to its scanning principle, lidar can be divided into coaxial rotation, prism rotation, MEMS, OPA phased array and flash. ? lidar is not only used for perception, but also for mapping and positioning.

Millimeter wave radar is mainly used for the detection of traffic vehicles. Millimeter wave radar is mainly composed of RF antenna, chip and algorithm. The basic principle is to transmit a beam of electromagnetic wave, and then observe the intake difference of electromagnetic wave echo to calculate the distance and speed.

It has the advantages of fast and accurate detection speed, no interference from weather conditions, and the disadvantage is that it can not identify and detect lane lines.

Integrated navigation is to receive all visible GPS satellite signals through GNSS board and calculate them, so as to get the spatial position of the object in the geodetic coordinate system.

When vehicles pass through tunnels, buildings and shaded roads, GPS signal can not provide a good settlement and real-time navigation, so it is necessary to integrate the information of inertial navigation.

Inertial navigation is a completely closed system, which can directly give the position, speed and attitude of the car body without any external influence.

automatic driving vehicle sensor installation location is generally: the

lidar is rotated at 360 degrees.As it is installed on the roof;

millimeter wave radar has strong aluminium sliding window lock manufacturer directivity, so it is generally installed on the front and rear bumpers;

considering the interference of the vehicle body's pitch and attitude on the Road, the integrated navigation system is generally installed on the central axis of the two rear wheels;

cameras are installed on 360 ° of the vehicle body.

The figure above summarizes the sensors used for autonomous driving.

Automatic Sliding window lock manufacturer cruise, emergency braking and pedestrian detection are all L1 and L2 functions.

The European standard is for vehicles with mandatory AEB function in 2017; the American standard is for all vehicles to have auxiliary driving, lane departure and AEB function by 2020;

the Chinese standard is to list the automatic driving L1 function AEB as mandatory standard by 2018, which are mainly used for commercial vehicles, trucks and buses.

The following is a brief introduction of the differences between the current mass production plans of L1 and L2 and the plans above L3 + developed by Baidu and many AI companies.

? grade L1 and grade L2 are most afraid of sensor error detection, for example, sensor error detection while driving, and then sudden braking will make driving feel bad. L1 and L2 algorithm can avoid certain aluminium alloy sliding door lock false detection rate.

Above L3, we pay attention to the missing detection of sensors. The main body of driving is a system. We must not allow the missing detection of the sensor section of the system.

This is the current traditional car companies and some AI companies in the automatic driving sensor for two major differencesDifferent.

At present, L4 adapts to some automatic driving on urban roads and expressways. The speed limit of expressways in China is 120km / h. according to the road friction coefficient, the braking distance at different speeds can be calculated. Add the reaction time of the whole system, and calculate the following table according to the mathematical formula.

At present, the reaction time of the whole system of automatic driving will be within 500ms. It takes 0.3-0.5s for the vehicle to brake hydraulically, and 0.8s for the truck to brake pneumatically.

At present, most of the cars on sale are lower than this technical index, which shows that the performance of the cars on sale is very good. At present, it is enough to measure 150 meters for the requirements of sensors.

This is a trigonometric function arctangent function, but this formula will be divided by one more 2 to avoid omission.

When there is an object between the angles of two beam lines of lidar, which is just at the detection edge, it will generate a certain amount of missed detection. Dividing by 2 is to ensure that there will be no missed detection at each angle. .

At the resolution of 0.1 °, we can actually detect a person, a car or a rider 400 meters away.

, however, can detect that it does not mean that the automatic driving system can be identified. Only one line of imaging or low resolution imaging can automatically identify the driver.

At present, on the baidu Apollo platform, we can use four or five lines of lidar on the same vehicle to classify the obstacles well.

Now, like velodyne's 64 line lidar, his object perception distance at 0.4 ° resolution is 50 meters.

The future trend of autopilot sensors: autopilot sensors can not do without multi-sensor fusion. Lidar and camera belong to optical sensors, and their core parts and processing circuits are very similar,

in the future, it is possible to integrate lidar and camera front-end, directly output RGB and XYZ fusion color plus point cloud information, and then transmit it to the back-end calculation for processing.

The iradar system developed by aeye, an American start-up company, can not only truly reflect the color information of two-dimensional world, but also overlay the information of point cloud. Each pixel has not only color information but also spatial coordinate information.

above is the calculation unit structure of the automatic driving vehicle. In the calculation unit of automatic driving vehicle,

needs to consider the overall vehicle gauge, electromagnetic interference and vibration design as well as the requirements of ISO-26262 standard.

All CPU, GPU, FPGA, MCU and bus should be designed redundantly to prevent single point failure.

At present, the computing unit is a centralized architecture, that is, all the work is put into an industrial computer.

The disadvantages of this architecture are large size, high power consumption and discomfortIt is convenient for fast code iteration, and the design of industrial computer card slot is convenient for hardware update and expansion?.

Because of the disadvantage of centralization, the embedded scheme will be considered in the future. First, the original data of each sensor is fused into a sensor box, in which data fusion is completed, and then the fused data is sent to the back-end computing platform for processing.

Function of sensor box: how to judge whether the original data given by the current sensor is the same target after the fusion is completed? A time stamp synchronization is required to ensure that each sensor detects the same coordinate system under the time stamp. The synchronization of time stamps is completed in the sensor box. ?

this scheme breaks down the original centralized computing function, which can reduce the power consumption of the whole system, but it is not enough for more mass production.

The self driving algorithm we are developing now can be made into a special chip when the sensing algorithm solidifies.

ASIC chip is a special customized chip based on specific requirements. Its advantages are smaller volume, lower power consumption, stable performance and mass production compared with general GPU and FPGA.

Now the semiconductor industry is very mature. sinceDynamic driving algorithm companies only need to do a good job in the front-end design of the chip, such as solidifying the algorithm, then choosing the appropriate IP core, and finally carrying out EDA (electronic automation design), and then handing the circuit diagram of the chip design to the back-end, chip manufacturing enterprises such as TSMC carry out the production of chips.

The whole chip design process is divided into three parts: chip design, chip manufacturing and chip packaging. Now the whole semiconductor industry is developing from deep ultraviolet (Dov) to extreme ultraviolet (EUV).

Semiconductor is stepping into the 7 nanometer era, and the new technology has brought great improvement to the performance. Compared with 16 nm process, 7 nm process can improve 40% performance and save 60% energy consumption.

Control by wire refers to that the control of the car is completed by some simple commands, not by physical operation.

The wire control part is equivalent to the human hand and foot, and the upper command is executed in the online control system. It is mainly divided into three parts: deceleration control, steering control and acceleration control.

these control systems of traditional cars are assisted by hydraulic system and vacuum booster pump. The automatic control of automobile must be controlled by electronically controlled components, such as electronic hydraulic braking system (EHB).

Solution. Its MK C1 integrates hydraulic and braking modules, uses compact and light weight design to save braking unit, and the braking signal sent by electrical signal also makes the braking distance shorter.

ESC (body electronic stability system) used by mk100 can back up with MK C1. When MK C1 system fails, mk100 will take over.

From the perspective of schematic diagram, all power supply, execution, circuit and pipeline diagrams of continental braking are double backup, which greatly improves the safety, but the system is only applicable to passenger vehicles. Commercial vehicles such as trucks and buses are braked by air brake system.

At present, many autonomous vehicles use EPS (electronic power steering system). The EPS directly uses the steering column in combination with the lower rack, without electrical control.

? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? The automatic driving vehicle's wire control system

, such as Infiniti Q50's steering system, is driven by a clutch to turn the steering column off. When the vehicle is started, the clutch is released. All the automatic driving commands transmit control commands through the ECU (electronic control element) to the two steering motors on the lower part for steering control.

The accelerator by wire is used to control the acceleration of the automatic driving vehicle. There is a position sensor on the deceleration brake pedal that can detect the brake depth. The sensor transmitsWhen EMS (engine brake system) is reached, the more air intake the valve, the faster acceleration.

?????????????????????????????????? - automatic driving vehicle's line control system

automatic driving vehicle at present mostly is the new energy source vehicle, the new energy vehicle completes the acceleration control by the drive motor torque control, from the entire line control, divides into three stages:

1.0 ? refit the steering wheel pedal of the original vehicle. After cutting off some steering columns, install a steering motor to conduct steering by controlling the motor. The disadvantage is that the system of the original vehicle has not been tested and verified, and there is a potential safety hazard.

2.0 based on the auxiliary driving system of the original vehicle, the CAN bus protocol is cracked, and the steering and braking of the vehicle are controlled by the command of the original vehicle bus.

3.0 a set of system developed from the vehicle chassis, the steering by wire control is completely customized according to the requirements of automatic driving, and the difference with 2.0 is that the redundancy and backup requirements are considered.

On July 4, 2018, the Apollo hardware development platform was officially released, with 15 new hardware manufacturers selecting models and also Apollo sensor units.

After adding the underlying abstraction layer (upgrading the original hardware reference design to a hardware development platform), the content of the hardware development platform is more abundant.

Some developers put forward the hardware reference design provided by BaiduAt present, it can't be bought or the supply cycle is very long.

Based on these demands, we have enriched the selection of hardware, and will release the sensors, industrial computers and control units that have passed our test and verification, so as to facilitate the selection of developers.

In the current reference design provided by Baidu, we divide it into Apollo platform certification and Apollo hardware development platform certification.

Apollo platform certification means that the sensors currently in use by Baidu are published after certification. For example, velodyne 64 line lidar is an Apollo platform certified product. We will provide data sets based on the sensors in use.

The authentication of Apollo hardware development platform is carried out at the level of Apollo code, such as the additional work of data acquisition and annotation of perception module and model training, which also needs to be completed by the developers themselves.

In the future, Apollo will continue to enrich the ecosystem, continue to provide chip and sensor support and selection.

The sensor box integrates all the sensor information into the sensor unit, completes the alignment of the whole time stamp, and transmits the pre-processing data to the back-end industrial computer computing unit for processing.

this is developed based on Baidu's use of sensors, not necessarily applicable to all developers. In the future, Apollo will introduce aXu expansion unit, and the unit with PCI card slot will be more flexible.

In the abstraction layer of Apollo, there areHardware interface, such as kernel driver, USP library, etc.

USP library is mainly used in CAN bus protocol. Because the CAN bus protocol of each vehicle factory / model / batch is different, the control instruction information is written in USP library for operation.

In the Apollo development platform, there is also Hal hardware abstraction layer, which is the middle development layer to prevent the whole system hardware kernel from crashing due to single hardware short circuit. Different hardware manufacturers can choose to open all the source code or publish the compiled code on the Apollo platform.

After Apollo completes the code entry, it will be published on GitHub. Developers do not need to develop different drivers for different hardware options.

Finally, it is the layout of the auto driving industry chain released by VSI.

The auto driving industry is a large-scale aggregation industry of 100000 scale industries, such as new energy, it, traffic communication, semiconductor artificial intelligence, mobile Internet, etc.

autopilot is the aggregate of material flow, energy flow and information flow. It is necessary to deeply integrate and cooperate with the hardware and software industry to ensure the success of the automatic driving industry.

A Bojun said:

in the learning process, developers can not only ask questions about the course content in the Applo developer community applet, but also exchange learning experience in the developer wechat group, and learn autonomous driving skills togetherOperation. The

developer community will also push the curriculum related technical dry cargo regularly on the official account, and will accompany you all the way to make progress. I wish the Apollo developers to successfully complete the advanced course of auto driving, and go further and further on the road of auto driving!

You are also welcome to post your learning notes in the Q & a section of the app. You can also join the developer communication community to exchange and interact with you, and have a good gift!

After watching / reading the course, upload the screenshot of your course notes in the developer community and the "community Q & a" section of the app. You can contact the community assistant to get a souvenir of Baidu's surroundings by hand written notes / computer documents. Let's hurry up and have a lift ~ Bixin ~

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certainheartrunaway · 5 years ago

Text

3 element 50MHz LFA-Q Super-Gainer Quad Style Yagi

Product Dimensions and Weight

Product Length: 25.0000M

Product Widtg: 1.0280M

A 3 element LFA-Q (Super-rigid Quad-style) Super-Light Quad Style Yagi for 50-50.5MHz

The LFA-Q Packs a bigger punch than a traditional Yagi with MUCH MORE GAIN per metre of boom

If it is GAIN you want from a small boom, this is the antenna for you! Wow, Super compact boom!!

Checkout the TX Factor online review! http://m0scu.uk/tx-factor-episode-7/

Another impressive design from G0KSC, ‘The Quad has been InnovAted!’ A Quad-style antenna with full wave length loop elements which provide a number of benefits. First, if the elements are of reasonable thickness (as ours are, they are not wire!) then good bandwidth coverage can be achieved. Next, up to around 7 elements (1.5wl) much better gain per metre of boom can be achieved than would otherwise be possible from a traditional Yagi covering the same bandwidth. Finally, with the dual-boom structure and 1/2” diameter elements, the LFA-Q is extremely rigid and can stand up to some serious weather conditions!

IDEAL PORTABLE OR SOTA USE!

Despite it’s rigidity, the LFA-Q is extremely light weight and this means even in strong winds, snow and ice the LFA-Q will hold its own.

Our antennas are constructed with the best quality materials in order the best mechanical construction can be achieved, not the cheapest and most profitable! Even a digital caliper is used (with an accuracy of .01mm) to measure the elements during production to ensure they are within 0.2mm of what they should be, this ensures they work as well as our software model predicts.

Marine grade Stainless Steel Fittings

Original Stauff Insulation clamps

Mill finished boom and elements for highest levels of accuracy

For more information Email here

Performance

Gain: 8.82dBi @ 50.1MHz

F/B: 24.04dB @ 50.1MHz

Peak Gain: 8.9dBi

Gain 10m above ground: 14.36dBi

Peak F/B: 16.95dB

Power Rating: 5kw

SWR: Below 1.4.1 from 50MHz to 50.5MHz

Boom Length: 1.98m

Loop Height: 50cms

Weight: 3kg/8lbs

Safe Wind Speed: 210Kph/130Mph

Turning Radius: 1.69m/5.77ft

Vertical Stacking: 2.75m

Customer comment on the LFA-Q:

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Performs extremely well – It replaced a MET 144 8T (remember them) that was about 20 years old – the gamma match had become unstable – suspect the trombone dielectric has aged/decayed.

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Specification

This antenna is made with a 1/2 inch (12.7mm) and 3/8 inch (9.525mm) diameter tube for the LFA-Q and the boom sections are 3/4” 19mm diameter. This antenna is not made cheaply, it is made to perform and to do so for many years with Marine Grade Stainless Steel fixings.

No figures are made up here as they are in some Ham Radio adverts, all performance figures are verified in the very latest software simulation packages with some antennas being professionally confirmed on an antenna range.

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futuristicbelieverpeanut-blog1 · 7 years ago

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CIS 513 Week 5 Midterm Exam – Strayer NEW

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Chapter 1 Through 4

Chapter 1 - Introduction to Wireless Communications

TRUE/FALSE

1. VoIP phones can carry analog data over the Internet.

2. WirelessHD can transfer video and sound at 7 Gbps and higher.

3. UWB WiGig has a range of up to 100 meters.

4. The ZigBee Alliance protocols enable devices like light switches to communicate with one another.

5. RFID technology is implemented by roadside assistance services to link a vehicle and driver to a central service center.

6. 4G technology uses 100% analog transmission for voice and data.

7. An AP connects wireless devices to the wired LAN.

8. DSL is an Internet access technology that uses cable TV lines to make a network connection.

9. The job market for wireless LAN professionals is saturated and likely to decline in coming years.

10. One advantage of wireless technology is that it is immune to interference sources.

MULTIPLE CHOICE

1. What type of device is built into a tablet computer and can send data over radio waves to another device such as a laser printer?

VoIP phone

access point

wireless NIC

Ethernet NIC

2. How can VoIP over Wi-Fi help save money?

by eliminating the need for a phone

by reducing the cost of a smartphone

by saving on cellular phone bills

by not requiring an access point

3. Where would you most likely find RFID tags around the house?

on product packages

in the plumbing

in the walls and ceilings

on the electrical lines

4. What is the typical range for the use of Bluetooth?

meters to kilometers

inches to feet

yards to miles

millimeters to inches

5. With what technology will you find radio modules and link managers?

RFID

Wi-Fi

GPS

Bluetooth

6. Which technology has a maximum range of about 10 meters, can transmit up to 10 Gbps, and is used to transmit high quality audio and video wirelessly?

Wi-Fi

UWB

Bluetooth

RFID

7. Automatic connections between what type of devices create a piconet?

VoIP

Bluetooth

Infrared

WirelessHD

8. In what type of wireless communication device will you find a repeater?

satellite

antenna

NFC

WNIC

9. What kind of network is built around the concept of low-power transmitters built on towers that can use the same radio frequency channel?

Wi-Fi 802.11 networks

UWB A/V networks

cellular telephone networks

GPS tracking networks

10. What type of cellular network uses 100 percent digital transmission for voice and data and can reach rates up to 150 Mbps?

CDMA

GSM

11. What kind of device does a WLAN use to facilitate communication between wireless computers?

Ethernet switch

access point

GPS hub

cell station

12. Which wireless standard provides for data transmission speeds up to 600 Mbps with a range up to 375 feet?

802.11g

802.16m

WiGig

802.11n

13. Which technology uses regular phone lines and transmits at speeds up to 256 Kbps?

POTS

ISDN

cable modem

14. Which communication technology should you use if you need to connect three offices which are all within 3 miles of each other at speeds up to 75 Mbps using antennas?

WiMax

DSL

ISDN

15. Where are you most likely to find the WAP2 protocol in use?

cellular phones

tablets

laptops

servers

16. What term refers to the combining of voice, video and text-processing and access to multiple network platforms from a single device?

access aggregation

digital convergence

digital landscape

network transparency

COMPLETION

1. Smartphones can use software that allow them to make ______________ phone calls over a wireless LAN instead of the cellular network.

2. Bluetooth communicates using small, low-power ______________ called radio modules.

3. In the future, most barcode functions are likely to be replaced by ___________ tags including for the purpose of inventory management.

4. To protect confidentiality, wireless data can be ______________ between the access point and wireless device, allowing only the recipient to decode the message.

5. The FCC, FDA, and EPA have established ________ exposure safety guidelines to limit the signal absorption rate of wireless device users.

MATCHING

motes

Bluetooth

DSL

UWB

J2ME

WiGig

link manager

WPAN

1. a wireless standard that enables devices to transmit data at up to 721.2 Kbps

over a typical maximum distance of 33 feet

2. a variation of the Java programming language designed for use in portable devices such as cellular phones

3. a very small network that typically extends to 10 meters or less

4. a technology used to transmit data over special telephone lines at 1.544 Mbps

5. an alliance of companies involved in developing a common wireless specification using the 60 GHz band

6. a technology used to transmit data over a telephone line

7. remote sensors used for collecting data from manufacturing equipment or for

scientific research

8. wireless communications technology that allows devices to transmit data at hundreds of megabits or even gigabits per second at short distances

9. a digital cellular technology that can send data at up to 21 Mbps over the cellular telephone network

10. special software in Bluetooth devices that helps identify other Bluetooth devices

SHORT ANSWER

1. Describe how RFID can enhance a family’s convenience in the kitchen.

2. Describe Bluetooth technology and how it can be used in a computing environment.

3. What is UWB and how might it be used in a home?

4. What is a piconet?

5. What does a repeater do in a satellite communication system?

6. How does a WLAN use an access point?

7. Describe a WMAN and discuss a technology a WMAN might use.

8. What is digital convergence and how might it affect how people use network devices?

9. Discuss the use of wireless technologies in home entertainment.

10. Discuss how radio signal interference can affect wireless devices.

Chapter 2 - Wireless Data Transmission

TRUE/FALSE

1. The ASCII code uses 16 bits to represent 128 different characters.

�� 2. Infrared light interferes with radio signals but is not affected by radio signals.

3. The height of a radio wave is called the amplitude of the wave.

4. Spread-spectrum signals are more susceptible to outside interference than narrow-band transmissions.

5. Hopping codes used in FHSS transmissions are configured on the base station by the network administrator.

MULTIPLE CHOICE

1. Which of the following is true about wireless radio signal transmissions?

they travel at the speed of light

they travel as discrete particles

they require an atmosphere to move

they require visible light

2. Which of the following is NOT true about infrared light?

it can be used in directed transmissions

it is less susceptible to interference from visible light sources

it can be used in diffused transmissions

all infrared signals are invisible

3. Which of the following transmits a signal in an infrared device?

diffuser

detector

emitter

antenna

4. Which of the following is NOT a limitation of using infrared wireless systems?

they lack mobility

someone can eavesdrop from another room

they use a line-of-sight principle

diffused transmissions have a range of 50 feet

5. Which of the following is a good application for an infrared wireless system?

stream movies from a server

whole house wireless network

wireless outdoor speakers

data transfer between laptop and camera

6. Which best describes an analog signal?

it starts and stops

consists of discrete pulses

intensity varies and is continuous

Morse code is an example

7. What process must occur to transmit a digital signal over an analog medium?

modulation

decoding

decoupling

emitting

8. The distance between a point in one wave cycle and the same point in the next wave cycle is called which of the following?

amplitude

carrier

wavelength

frequency

9. The frequency of a wave is best defined as which of the following?

encoding of bits onto an analog wave

a carrier wave that has been modulated

the voltage difference between the peak and trough of the wave

the number of times a cycle occurs within one second

10. What is the unit of measurement for radio frequency?

volt

rpm

amp

11. What is the role of an antenna on a wireless device?

it receives data

it serves as a ground signal

it demodulates

it transmits and receives data

12. Which of the following is true about baud rate?

only one bit can be transferred per signal unit (baud)

a baud rate of 2400 always means a bandwidth of 2400 bps

multiple bits can be transferred with each signal unit

multiple signal units are needed to represent each bit

13. Which of the following best describes bandwidth in an analog system?

the range of frequencies that can be transmitted by a system

the number of bytes transmitted per minute

the number of bits transmitted per second

the maximum frequency supported by the medium

14. Which of the following is NOT a type of modulation that can be applied to an analog signal?

phase

frequency

carrier

amplitude

15. Which type of radio signal is most susceptible from interference sources such as lightning?

16. Which of the following is NOT an advantage of digital modulation over analog modulation?

better use of bandwidth

better performance during interference

requires less power

modulation techniques are simpler

17. Which binary signaling technique reduces the voltage to zero during the transmission of a 1 bit before the bit period ends.

NRZ-L

NRZ-I

NRZ

18. Which binary modulation technique employs NRZ coding such that the absence of a carrier signal represents a 0 bit?

ASK

FSK

BPSK

PSK

19. Which radio transmission method uses a chipping code?

DSSS

FHSS

20. Which of the following is a spread spectrum technique that employs mathematical algorithms to recover lost data bits?

frequency hopping

narrow band

direct sequence

wide band

COMPLETION

1. Data signals in a wireless communication system travel on _______________ waves.

2. A signal that is broadcast as a continuous wave is called a(n) _______________ signal.

3. When representing a wave with a garden hose, the distance between the peaks of the waves represents the ____________.

4. The _______________ non-return-to-zero encoding method represents a 1 bit by increasing voltage to a positive value and a 0 bit by decreasing the voltage to a negative value.

5. In the presence of background interference, receivers can detect a ____________ change more reliably than a frequency or amplitude change.

MATCHING

ASCII

digital modulation

amplitude modulation

frequency modulation

analog signal

hopping code

baud rate

NRZ

carrier signal

1. a method of encoding a digital signal onto an analog carrier wave for transmission over media that does not support direct digital signal transmission

2. the number of times that a carrier signal changes per second

3. a technique that changes the number of wave cycles in response to a change in the amplitude of the input signal

4. a binary signaling technique that increases the voltage to represent a 1 bit but provides no voltage for a 0 bit

5. a technique that changes the height of a carrier wave in response to a change in the height of the input signal

6. a signal of a particular frequency that is modulated to contain either analog or digital data

7. a technique that changes the starting point of a wave cycle in response to a change in the amplitude of the input signal

8. the sequence of changing frequencies used in FHSS

9. a coding scheme that uses the numbers from 0 to 127 to represent alphanumeric characters and symbols

10. a signal in which the intensity (amplitude or voltage) varies continuously and smoothly over a period of time

SHORT ANSWER

1. Describe the components in an infrared wireless system.

2. What are the advantages and limitations of an infrared wireless system?

3. Contrast analog signals with digital signals.

4. Describe how radio transmitters use a carrier signal.

5. How are radio waves transmitted using an antenna?

6. What are the three types of modulation that can be applied to an analog signal to enable it to carry information?

7. Describe amplitude modulation.

8. Describe the NRZ technique of representing bit signals.

9. What is phase shift keying? Describe how it works.

10. How are bits transmitted using DSSS? Include the chipping code in your answer.

Chapter 3 - Radio Frequency Communications

TRUE/FALSE

1. A high-pass filter allows all signals above a minimum threshold to pass through.

2. A mixer separates an input into two or more outputs.

3. TDMA was developed to overcome the problem of crosstalk.

4. A disadvantage of CDMA is that it can only carry one third the amount of data of TDMA.

5. There are no power limits imposed on devices using the unregulated bands.

MULTIPLE CHOICE

1. Which of the following is NOT a common component of all radio systems?

filter

mixer

emitter

antenna

2. Which of the following is a type of RF filter?

top-pass

bandpass

mid-pass

medipass

3. If a low-pass filter is set at 2200 MHz, which of the following signals would be allowed to pass through?

2400 MHz

1000 MHz

1500 GHz

23000 KHz

4. What kind of signals can result from the process of modulating a signal with data to be transmitted?

harmonics

modulators

passbands

sidebands

5. The sidebands of a frequency carrier are best described as which of the following?

the sum of the carrier signal and the highest value of the mixer output

the average of the high and low values of the input signal

the difference between the highest and lowest input frequency

the sum and difference of the highest input signal and carrier frequency

6. Which type of device is considered active device because it adds power to a signal?

mixer

antenna

filter

amplifier

7. Which of the following would take a transmission band of 1000 Hz and divide it into 100 channels of 10 Hz each to accommodate multiple access?

FDMA

CDMA

TDMA

SDMA

8. Which multiple access method overcomes the problem of crosstalk and divides the transmission time into several slots?

SDMA

TDMA

CDMA

FDMA

9. Which multiple access method uses a spreading code?

CDMA

SDMA

TDMA

FDMA

10. What type of transmission is a broadcast radio station an example of?

duplex

simplex

half-simplex

half-duplex

11. Which type of switching is used in a POTS system?

packet switching

cellular switching

circuit switching

frame switching

12. What can take place when signal strength falls close to or below the level of noise?

SNR

crosstalk

interference

attenuation

13. Objects in the path of a radio signal can cause which of the following?

crosstalk

EMI

amplification

attenuation

14. What is the term for signals that get reflected and travel different paths between transmitter and receiver arrive out of phase?

electro-magnetic interference

multipath distortion

reflective attenuation

phase misalignment

15. What problem can a directional antenna reduce in severity?

reflective attenuation

phase misalignment

multipath distortion

electro-magnetic interference

16. Which type of standard is an official standard controlled by and organization or body open to everyone?

de jure standards

consortia standards

de facto standards

paramount standards

17. Which standards organization functions as a clearinghouse for many types of standards development in the U.S.?

ETSI

ANSI

IETF

ISOC

18. Which standards body deals with user-premises equipment and satellite communications?

IAB

IETF

TIA

ISCO

19. Which international standards organization coordinates global communications networks and services and is actually a treaty organization?

IAB

ISO

TIA

ITU

20. In which frequency band will you find an 802.11 network?

medium frequency (MF)

extremely high frequency (EHF)

super high frequency (SHF)

very high frequency (VHF)

COMPLETION

1. A __________________ filter sets a range of frequencies that include a minimum and maximum threshold.

2. _________________ uses direct sequence spread spectrum technology.

3. ____________________ transmission is typically used in consumer devices such as CB radios or walkie talkies where you have to hold down a button while speaking.

4. A technique called ______________ array processing replaces a traditional antenna

5. _______________ transmission uses low-power, precisely timed pulses of energy that operate in the same frequency spectrum as low-end noise and is used in WiGig.

MATCHING

circuit switching

license exempt spectrum

directional antenna

packet switching

full-duplex transmission

signal-to-noise ratio

half-duplex transmission

simplex transmission

harmonics

switching

1. transmission that occurs in both directions but only one way at a time

2. a switching technique in which a dedicated and direct physical connection is made between two transmitting devices

3. transmission that occurs in only one direction

4. unregulated radio frequency bands that are available in the United States to any users without a license

5. transmissions in which data flows in either direction simultaneously

6. moving a signal from one wire or frequency to another

7. data transmission that is broken into smaller units

8. an antenna that radiates the electromagnetic waves in one direction only

9. stray oscillations that result from the process of modulating a wave and that

fall outside the range of frequencies used for transmission

10. the measure of signal strength relative to the background noise

SHORT ANSWER

1. What does a filter do and why is one needed in a radio system?

2. List the three types of RF filters.

3. Why are filters found in transmitters?

4. What is the purpose of a mixer? Include a discussion of sidebands in your answer.

5. What is an amplifier and why is it a crucial component in a radio system?

6. Describe time division multiple access.

7. What are two advantages that TDMA has over FDMA?

8. What are three advantages of CDMA over TDMA?

9. What advantages does packet switching have over circuit switching for transmitting data?

10. What is multipath distortion?

Chapter 4 - How Antennas Work

TRUE/FALSE

1. Cables and connectors offer resistance to the flow of electricity, increasing the power of a signal.

2. Decibels are an absolute measurement of signal strength, making it simpler to calculate gain or loss.

3. The size of an antenna is directly proportional to the wavelength of the signal it is designed to transmit and receive.

4. A monopole antenna is a type of two-dimensional antenna.

5. Point-to-point wireless links are best served by using omnidirectional antennas.

MULTIPLE CHOICE

1. Which of the following is likely to result in a wireless signal gain?

cables

connectors

amplifier

atmosphere

2. What unit of measurement is a ratio between two signal levels?

volt

decibel

watt

ohm

3. Which value indicates the signal being measured is twice the power?

+3 dB

+5 mW

-5 dB

-3 mW

4. If a signal is represented as 15 mW + 10 db, what is the resulting signal strength in mW?

30 mW

75 mW

25 mW

150 mW

5. Which of the following refers to the gain an antenna has over a dipole antenna at the same frequency?

dBm

dBi

dBd

dBg

6. Which of the following is true about antennas?

the size is proportional to the wavelength

most are active devices

lower frequency signals require larger antennas

omnidirectional types provide the best directional gain

7. Which of the following is true about omnidirectional antennas?

they work best in point-to-point links

longer ones usually have higher gain

they cannot be used in 802.11 applications

they emit a signal in three dimensions

8. Which type of directional antenna is used for outdoor applications up to 16 miles?

cellular

parabolic dish

patch

yagi

9. A cellular phone antenna that is 13 inches long would be considered which of the following?

eighth-wave

half-wave

quarter-wave

full-wave

10. If an antenna is much longer than the wavelength, what is the typical result?

inefficient delivery of RF energy

wrong signal frequency

signals that are an incorrect wavelength

no signal is transmitted

11. What does antenna polarization determine about the performance of the antenna?

radiation pattern

measurement of signals is positive or negative voltage

horizontal or vertical orientation

direction of the signal

12. What type of antenna is a straight piece of wire with no reflecting ground element?

monopole

horn

dipole

dish

13. Which type of antenna is two-dimensional, is common in telephone networks, and is used to transmit high-power microwave signals between towers?

patch

horn

satellite dish

dipole

14. What type of antenna is divided into a matrix of radiating elements and are used in modern radar systems?

switched beam

patch

horn

phased array

15. When a coaxial cable connects the antenna to the transmitter, what property of the cable must match that of the antenna?

impedance

length

thickness

inductance

16. What type of wave propagation do RF signals transmitted at 50 MHz have?

ground waves

line-of-sight waves

sky waves

atmospheric waves

17. Which type of antenna should usually be used at the central location in a point-to-multipoint wireless link?

unidirectional

directional

omnidirectional

semi-directional

18. Which of the following is the elliptical region within which signals travel between two antennas in a point-to-point link?

troposphere radius

Fresnel zone

propagation limit

wave pattern

19. What is the signal strength necessary to meet a receiver’s minimum requirements?

transmission path

minimum wavelength

Fresnel zone

link budget

20. What is the maximum percent of the Fresnel zone that can be blocked by obstructions in a point-to-point link?

20%

40%

60%

10%

COMPLETION

1. ______________ is the effect of an amplifier boosting the power of a signal.

2. A radio signal’s power does not change in a linear fashion, but instead changes ______________.

3. _____________ is a relative measurement used to represent gain or loss in a signal.

4. When considering antenna size, lower frequencies require ___________ antennas.

5. A _________________ analyzer is a tool that displays the signal amplitude and frequency of a radio transmission.

MATCHING

antenna pattern

ground-plane

dB isotropic

isotropic radiator

dBm

passive antenna

dipole

patch antenna

free space loss

smart antenna

1. the signal loss that occurs as a result of the tendency of RF waves to spread

2. a theoretically perfect sphere that radiates power equally in all directions

3. the relative measurement of the gain of an antenna when compared to a theoretical isotropic radiator

4. a new type of antenna that uses a signal processor and an array of narrow beam elements

5. a graphic that shows how a signal radiates out of an antenna

6. a semi-directional antenna that emits a wide horizontal beam and an even

wider vertical beam

7. a metal disc or two straight wires assembled at 90 degrees, used to provide

a reflection point for monopole antennas

8. a relative way to indicate an absolute power level in the linear watt scale

9. can only radiate a signal with the same amount of energy that appears at the antenna connector

10. an antenna that has a fixed amount of gain over that of an isotropic radiator

SHORT ANSWER

1. List three of the four aspects of RF signal transmission you need to know.

2. Describe the “tens and threes of RF mathematics”.

3. What is an isotropic radiator?

4. Describe directional gain and how it can be accomplished with a passive antenna.

5. What are two types of directional antenna? Describe them.

6. What is free space loss? Describe how it occurs.

7. How does the size of an antenna affect its ability to transmit and receive?

8. What does an antenna pattern show about the RF wave?

9. What does antenna polarization tell you about the antenna wave? How is it important for signal reception?

10. Give two examples of two-dimensional antennas. Describe them.

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Chapter 1 Through 4

Chapter 1 - Introduction to Wireless Communications

TRUE/FALSE

1. VoIP phones can carry analog data over the Internet.

2. WirelessHD can transfer video and sound at 7 Gbps and higher.

3. UWB WiGig has a range of up to 100 meters.

4. The ZigBee Alliance protocols enable devices like light switches to communicate with one another.

5. RFID technology is implemented by roadside assistance services to link a vehicle and driver to a central service center.

6. 4G technology uses 100% analog transmission for voice and data.

7. An AP connects wireless devices to the wired LAN.

8. DSL is an Internet access technology that uses cable TV lines to make a network connection.

9. The job market for wireless LAN professionals is saturated and likely to decline in coming years.

10. One advantage of wireless technology is that it is immune to interference sources.

MULTIPLE CHOICE

1. What type of device is built into a tablet computer and can send data over radio waves to another device such as a laser printer?

VoIP phone

access point

wireless NIC

Ethernet NIC

2. How can VoIP over Wi-Fi help save money?

by eliminating the need for a phone

by reducing the cost of a smartphone

by saving on cellular phone bills

by not requiring an access point

3. Where would you most likely find RFID tags around the house?

on product packages

in the plumbing

in the walls and ceilings

on the electrical lines

4. What is the typical range for the use of Bluetooth?

meters to kilometers

inches to feet

yards to miles

millimeters to inches

5. With what technology will you find radio modules and link managers?

RFID

Wi-Fi

GPS

Bluetooth

6. Which technology has a maximum range of about 10 meters, can transmit up to 10 Gbps, and is used to transmit high quality audio and video wirelessly?

Wi-Fi

UWB

Bluetooth

RFID

7. Automatic connections between what type of devices create a piconet?

VoIP

Bluetooth

Infrared

WirelessHD

8. In what type of wireless communication device will you find a repeater?

satellite

antenna

NFC

WNIC

9. What kind of network is built around the concept of low-power transmitters built on towers that can use the same radio frequency channel?

Wi-Fi 802.11 networks

UWB A/V networks

cellular telephone networks

GPS tracking networks

10. What type of cellular network uses 100 percent digital transmission for voice and data and can reach rates up to 150 Mbps?

CDMA

GSM

11. What kind of device does a WLAN use to facilitate communication between wireless computers?

Ethernet switch

access point

GPS hub

cell station

12. Which wireless standard provides for data transmission speeds up to 600 Mbps with a range up to 375 feet?

802.11g

802.16m

WiGig

802.11n

13. Which technology uses regular phone lines and transmits at speeds up to 256 Kbps?

POTS

ISDN

cable modem

14. Which communication technology should you use if you need to connect three offices which are all within 3 miles of each other at speeds up to 75 Mbps using antennas?

WiMax

DSL

ISDN

15. Where are you most likely to find the WAP2 protocol in use?

cellular phones

tablets

laptops

servers

16. What term refers to the combining of voice, video and text-processing and access to multiple network platforms from a single device?

access aggregation

digital convergence

digital landscape

network transparency

COMPLETION

1. Smartphones can use software that allow them to make ______________ phone calls over a wireless LAN instead of the cellular network.

2. Bluetooth communicates using small, low-power ______________ called radio modules.

3. In the future, most barcode functions are likely to be replaced by ___________ tags including for the purpose of inventory management.

4. To protect confidentiality, wireless data can be ______________ between the access point and wireless device, allowing only the recipient to decode the message.

5. The FCC, FDA, and EPA have established ________ exposure safety guidelines to limit the signal absorption rate of wireless device users.

MATCHING

motes

Bluetooth

DSL

UWB

J2ME

WiGig

link manager

WPAN

1. a wireless standard that enables devices to transmit data at up to 721.2 Kbps

over a typical maximum distance of 33 feet

2. a variation of the Java programming language designed for use in portable devices such as cellular phones

3. a very small network that typically extends to 10 meters or less

4. a technology used to transmit data over special telephone lines at 1.544 Mbps

5. an alliance of companies involved in developing a common wireless specification using the 60 GHz band

6. a technology used to transmit data over a telephone line

7. remote sensors used for collecting data from manufacturing equipment or for

scientific research

8. wireless communications technology that allows devices to transmit data at hundreds of megabits or even gigabits per second at short distances

9. a digital cellular technology that can send data at up to 21 Mbps over the cellular telephone network

10. special software in Bluetooth devices that helps identify other Bluetooth devices

SHORT ANSWER

1. Describe how RFID can enhance a family’s convenience in the kitchen.

2. Describe Bluetooth technology and how it can be used in a computing environment.

3. What is UWB and how might it be used in a home?

4. What is a piconet?

5. What does a repeater do in a satellite communication system?

6. How does a WLAN use an access point?

7. Describe a WMAN and discuss a technology a WMAN might use.

8. What is digital convergence and how might it affect how people use network devices?

9. Discuss the use of wireless technologies in home entertainment.

10. Discuss how radio signal interference can affect wireless devices.

Chapter 2 - Wireless Data Transmission

TRUE/FALSE

1. The ASCII code uses 16 bits to represent 128 different characters.

2. Infrared light interferes with radio signals but is not affected by radio signals.

3. The height of a radio wave is called the amplitude of the wave.

4. Spread-spectrum signals are more susceptible to outside interference than narrow-band transmissions.

5. Hopping codes used in FHSS transmissions are configured on the base station by the network administrator.

MULTIPLE CHOICE

1. Which of the following is true about wireless radio signal transmissions?

they travel at the speed of light

they travel as discrete particles

they require an atmosphere to move

they require visible light

2. Which of the following is NOT true about infrared light?

it can be used in directed transmissions

it is less susceptible to interference from visible light sources

it can be used in diffused transmissions

all infrared signals are invisible

3. Which of the following transmits a signal in an infrared device?

diffuser

detector

emitter

antenna

4. Which of the following is NOT a limitation of using infrared wireless systems?

they lack mobility

someone can eavesdrop from another room

they use a line-of-sight principle

diffused transmissions have a range of 50 feet

5. Which of the following is a good application for an infrared wireless system?

stream movies from a server

whole house wireless network

wireless outdoor speakers

data transfer between laptop and camera

6. Which best describes an analog signal?

it starts and stops

consists of discrete pulses

intensity varies and is continuous

Morse code is an example

7. What process must occur to transmit a digital signal over an analog medium?

modulation

decoding

decoupling

emitting

8. The distance between a point in one wave cycle and the same point in the next wave cycle is called which of the following?

amplitude

carrier

wavelength

frequency

9. The frequency of a wave is best defined as which of the following?

encoding of bits onto an analog wave

a carrier wave that has been modulated

the voltage difference between the peak and trough of the wave

the number of times a cycle occurs within one second

10. What is the unit of measurement for radio frequency?

volt

rpm

amp

11. What is the role of an antenna on a wireless device?

it receives data

it serves as a ground signal

it demodulates

it transmits and receives data

12. Which of the following is true about baud rate?

only one bit can be transferred per signal unit (baud)

a baud rate of 2400 always means a bandwidth of 2400 bps

multiple bits can be transferred with each signal unit

multiple signal units are needed to represent each bit

13. Which of the following best describes bandwidth in an analog system?

the range of frequencies that can be transmitted by a system

the number of bytes transmitted per minute

the number of bits transmitted per second

the maximum frequency supported by the medium

14. Which of the following is NOT a type of modulation that can be applied to an analog signal?

phase

frequency

carrier

amplitude

15. Which type of radio signal is most susceptible from interference sources such as lightning?

16. Which of the following is NOT an advantage of digital modulation over analog modulation?

better use of bandwidth

better performance during interference

requires less power

modulation techniques are simpler

17. Which binary signaling technique reduces the voltage to zero during the transmission of a 1 bit before the bit period ends.

NRZ-L

NRZ-I

NRZ

18. Which binary modulation technique employs NRZ coding such that the absence of a carrier signal represents a 0 bit?

ASK

FSK

BPSK

PSK

19. Which radio transmission method uses a chipping code?

DSSS

FHSS

20. Which of the following is a spread spectrum technique that employs mathematical algorithms to recover lost data bits?

frequency hopping

narrow band

direct sequence

wide band

COMPLETION

1. Data signals in a wireless communication system travel on _______________ waves.

2. A signal that is broadcast as a continuous wave is called a(n) _______________ signal.

3. When representing a wave with a garden hose, the distance between the peaks of the waves represents the ____________.

4. The _______________ non-return-to-zero encoding method represents a 1 bit by increasing voltage to a positive value and a 0 bit by decreasing the voltage to a negative value.

5. In the presence of background interference, receivers can detect a ____________ change more reliably than a frequency or amplitude change.

MATCHING

ASCII

digital modulation

amplitude modulation

frequency modulation

analog signal

hopping code

baud rate

NRZ

carrier signal

1. a method of encoding a digital signal onto an analog carrier wave for transmission over media that does not support direct digital signal transmission

2. the number of times that a carrier signal changes per second

3. a technique that changes the number of wave cycles in response to a change in the amplitude of the input signal

4. a binary signaling technique that increases the voltage to represent a 1 bit but provides no voltage for a 0 bit

5. a technique that changes the height of a carrier wave in response to a change in the height of the input signal

6. a signal of a particular frequency that is modulated to contain either analog or digital data

7. a technique that changes the starting point of a wave cycle in response to a change in the amplitude of the input signal

8. the sequence of changing frequencies used in FHSS

9. a coding scheme that uses the numbers from 0 to 127 to represent alphanumeric characters and symbols

10. a signal in which the intensity (amplitude or voltage) varies continuously and smoothly over a period of time

SHORT ANSWER

1. Describe the components in an infrared wireless system.

2. What are the advantages and limitations of an infrared wireless system?

3. Contrast analog signals with digital signals.

4. Describe how radio transmitters use a carrier signal.

5. How are radio waves transmitted using an antenna?

6. What are the three types of modulation that can be applied to an analog signal to enable it to carry information?

7. Describe amplitude modulation.

8. Describe the NRZ technique of representing bit signals.

9. What is phase shift keying? Describe how it works.

10. How are bits transmitted using DSSS? Include the chipping code in your answer.

Chapter 3 - Radio Frequency Communications

TRUE/FALSE

1. A high-pass filter allows all signals above a minimum threshold to pass through.

2. A mixer separates an input into two or more outputs.

3. TDMA was developed to overcome the problem of crosstalk.

4. A disadvantage of CDMA is that it can only carry one third the amount of data of TDMA.

5. There are no power limits imposed on devices using the unregulated bands.

MULTIPLE CHOICE

1. Which of the following is NOT a common component of all radio systems?

filter

mixer

emitter

antenna

2. Which of the following is a type of RF filter?

top-pass

bandpass

mid-pass

medipass

3. If a low-pass filter is set at 2200 MHz, which of the following signals would be allowed to pass through?

2400 MHz

1000 MHz

1500 GHz

23000 KHz

4. What kind of signals can result from the process of modulating a signal with data to be transmitted?

harmonics

modulators

passbands

sidebands

5. The sidebands of a frequency carrier are best described as which of the following?

the sum of the carrier signal and the highest value of the mixer output

the average of the high and low values of the input signal

the difference between the highest and lowest input frequency

the sum and difference of the highest input signal and carrier frequency

6. Which type of device is considered active device because it adds power to a signal?

mixer

antenna

filter

amplifier

7. Which of the following would take a transmission band of 1000 Hz and divide it into 100 channels of 10 Hz each to accommodate multiple access?

FDMA

CDMA

TDMA

SDMA

8. Which multiple access method overcomes the problem of crosstalk and divides the transmission time into several slots?

SDMA

TDMA

CDMA

FDMA

9. Which multiple access method uses a spreading code?

CDMA

SDMA

TDMA

FDMA

10. What type of transmission is a broadcast radio station an example of?

duplex

simplex

half-simplex

half-duplex

11. Which type of switching is used in a POTS system?

packet switching

cellular switching

circuit switching

frame switching

12. What can take place when signal strength falls close to or below the level of noise?

SNR

crosstalk

interference

attenuation

13. Objects in the path of a radio signal can cause which of the following?

crosstalk

EMI

amplification

attenuation

14. What is the term for signals that get reflected and travel different paths between transmitter and receiver arrive out of phase?

electro-magnetic interference

multipath distortion

reflective attenuation

phase misalignment

15. What problem can a directional antenna reduce in severity?

reflective attenuation

phase misalignment

multipath distortion

electro-magnetic interference

16. Which type of standard is an official standard controlled by and organization or body open to everyone?

de jure standards

consortia standards

de facto standards

paramount standards

17. Which standards organization functions as a clearinghouse for many types of standards development in the U.S.?

ETSI

ANSI

IETF

ISOC

18. Which standards body deals with user-premises equipment and satellite communications?

IAB

IETF

TIA

ISCO

19. Which international standards organization coordinates global communications networks and services and is actually a treaty organization?

IAB

ISO

TIA

ITU

20. In which frequency band will you find an 802.11 network?

medium frequency (MF)

extremely high frequency (EHF)

super high frequency (SHF)

very high frequency (VHF)

COMPLETION

1. A __________________ filter sets a range of frequencies that include a minimum and maximum threshold.

2. _________________ uses direct sequence spread spectrum technology.

3. ____________________ transmission is typically used in consumer devices such as CB radios or walkie talkies where you have to hold down a button while speaking.

4. A technique called ______________ array processing replaces a traditional antenna

5. _______________ transmission uses low-power, precisely timed pulses of energy that operate in the same frequency spectrum as low-end noise and is used in WiGig.

MATCHING

circuit switching

license exempt spectrum

directional antenna

packet switching

full-duplex transmission

signal-to-noise ratio

half-duplex transmission

simplex transmission

harmonics

switching

1. transmission that occurs in both directions but only one way at a time

2. a switching technique in which a dedicated and direct physical connection is made between two transmitting devices

3. transmission that occurs in only one direction

4. unregulated radio frequency bands that are available in the United States to any users without a license

5. transmissions in which data flows in either direction simultaneously

6. moving a signal from one wire or frequency to another

7. data transmission that is broken into smaller units

8. an antenna that radiates the electromagnetic waves in one direction only

9. stray oscillations that result from the process of modulating a wave and that

fall outside the range of frequencies used for transmission

10. the measure of signal strength relative to the background noise

SHORT ANSWER

1. What does a filter do and why is one needed in a radio system?

2. List the three types of RF filters.

3. Why are filters found in transmitters?

4. What is the purpose of a mixer? Include a discussion of sidebands in your answer.

5. What is an amplifier and why is it a crucial component in a radio system?

6. Describe time division multiple access.

7. What are two advantages that TDMA has over FDMA?

8. What are three advantages of CDMA over TDMA?

9. What advantages does packet switching have over circuit switching for transmitting data?

10. What is multipath distortion?

Chapter 4 - How Antennas Work

TRUE/FALSE

1. Cables and connectors offer resistance to the flow of electricity, increasing the power of a signal.

2. Decibels are an absolute measurement of signal strength, making it simpler to calculate gain or loss.

3. The size of an antenna is directly proportional to the wavelength of the signal it is designed to transmit and receive.

4. A monopole antenna is a type of two-dimensional antenna.

5. Point-to-point wireless links are best served by using omnidirectional antennas.

MULTIPLE CHOICE

1. Which of the following is likely to result in a wireless signal gain?

cables

connectors

amplifier

atmosphere

2. What unit of measurement is a ratio between two signal levels?

volt

decibel

watt

ohm

3. Which value indicates the signal being measured is twice the power?

+3 dB

+5 mW

-5 dB

-3 mW

4. If a signal is represented as 15 mW + 10 db, what is the resulting signal strength in mW?

30 mW

75 mW

25 mW

150 mW

5. Which of the following refers to the gain an antenna has over a dipole antenna at the same frequency?

dBm

dBi

dBd

dBg

6. Which of the following is true about antennas?

the size is proportional to the wavelength

most are active devices

lower frequency signals require larger antennas

omnidirectional types provide the best directional gain

7. Which of the following is true about omnidirectional antennas?

they work best in point-to-point links

longer ones usually have higher gain

they cannot be used in 802.11 applications

they emit a signal in three dimensions

8. Which type of directional antenna is used for outdoor applications up to 16 miles?

cellular

parabolic dish

patch

yagi

9. A cellular phone antenna that is 13 inches long would be considered which of the following?

eighth-wave

half-wave

quarter-wave

full-wave

10. If an antenna is much longer than the wavelength, what is the typical result?

inefficient delivery of RF energy

wrong signal frequency

signals that are an incorrect wavelength

no signal is transmitted

11. What does antenna polarization determine about the performance of the antenna?

radiation pattern

measurement of signals is positive or negative voltage

horizontal or vertical orientation

direction of the signal

12. What type of antenna is a straight piece of wire with no reflecting ground element?

monopole

horn

dipole

dish

13. Which type of antenna is two-dimensional, is common in telephone networks, and is used to transmit high-power microwave signals between towers?

patch

horn

satellite dish

dipole

14. What type of antenna is divided into a matrix of radiating elements and are used in modern radar systems?

switched beam

patch

horn

phased array

15. When a coaxial cable connects the antenna to the transmitter, what property of the cable must match that of the antenna?

impedance

length

thickness

inductance

16. What type of wave propagation do RF signals transmitted at 50 MHz have?

ground waves

line-of-sight waves

sky waves

atmospheric waves

17. Which type of antenna should usually be used at the central location in a point-to-multipoint wireless link?

unidirectional

directional

omnidirectional

semi-directional

18. Which of the following is the elliptical region within which signals travel between two antennas in a point-to-point link?

troposphere radius

Fresnel zone

propagation limit

wave pattern

19. What is the signal strength necessary to meet a receiver’s minimum requirements?

transmission path

minimum wavelength

Fresnel zone

link budget

20. What is the maximum percent of the Fresnel zone that can be blocked by obstructions in a point-to-point link?

20%

40%

60%

10%

COMPLETION

1. ______________ is the effect of an amplifier boosting the power of a signal.

2. A radio signal’s power does not change in a linear fashion, but instead changes ______________.

3. _____________ is a relative measurement used to represent gain or loss in a signal.

4. When considering antenna size, lower frequencies require ___________ antennas.

5. A _________________ analyzer is a tool that displays the signal amplitude and frequency of a radio transmission.

MATCHING

antenna pattern

ground-plane

dB isotropic

isotropic radiator

dBm

passive antenna

dipole

patch antenna

free space loss

smart antenna

1. the signal loss that occurs as a result of the tendency of RF waves to spread

2. a theoretically perfect sphere that radiates power equally in all directions

3. the relative measurement of the gain of an antenna when compared to a theoretical isotropic radiator

4. a new type of antenna that uses a signal processor and an array of narrow beam elements

5. a graphic that shows how a signal radiates out of an antenna

6. a semi-directional antenna that emits a wide horizontal beam and an even

wider vertical beam

7. a metal disc or two straight wires assembled at 90 degrees, used to provide

a reflection point for monopole antennas

8. a relative way to indicate an absolute power level in the linear watt scale

9. can only radiate a signal with the same amount of energy that appears at the antenna connector

10. an antenna that has a fixed amount of gain over that of an isotropic radiator

SHORT ANSWER

1. List three of the four aspects of RF signal transmission you need to know.

2. Describe the “tens and threes of RF mathematics”.

3. What is an isotropic radiator?

4. Describe directional gain and how it can be accomplished with a passive antenna.

5. What are two types of directional antenna? Describe them.

6. What is free space loss? Describe how it occurs.

7. How does the size of an antenna affect its ability to transmit and receive?

8. What does an antenna pattern show about the RF wave?

9. What does antenna polarization tell you about the antenna wave? How is it important for signal reception?

10. Give two examples of two-dimensional antennas. Describe them.

#CIS 513 Week 5 Midterm Exam – Strayer NEW

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Chapter 1 Through 4

Chapter 1 - Introduction to Wireless Communications

TRUE/FALSE

1. VoIP phones can carry analog data over the Internet.

2. WirelessHD can transfer video and sound at 7 Gbps and higher.

3. UWB WiGig has a range of up to 100 meters.

4. The ZigBee Alliance protocols enable devices like light switches to communicate with one another.

5. RFID technology is implemented by roadside assistance services to link a vehicle and driver to a central service center.

6. 4G technology uses 100% analog transmission for voice and data.

7. An AP connects wireless devices to the wired LAN.

8. DSL is an Internet access technology that uses cable TV lines to make a network connection.

9. The job market for wireless LAN professionals is saturated and likely to decline in coming years.

10. One advantage of wireless technology is that it is immune to interference sources.

MULTIPLE CHOICE

1. What type of device is built into a tablet computer and can send data over radio waves to another device such as a laser printer?

VoIP phone

access point

wireless NIC

Ethernet NIC

2. How can VoIP over Wi-Fi help save money?

by eliminating the need for a phone

by reducing the cost of a smartphone

by saving on cellular phone bills

by not requiring an access point

3. Where would you most likely find RFID tags around the house?

on product packages

in the plumbing

in the walls and ceilings

on the electrical lines

4. What is the typical range for the use of Bluetooth?

meters to kilometers

inches to feet

yards to miles

millimeters to inches

5. With what technology will you find radio modules and link managers?

RFID

Wi-Fi

GPS

Bluetooth

6. Which technology has a maximum range of about 10 meters, can transmit up to 10 Gbps, and is used to transmit high quality audio and video wirelessly?

Wi-Fi

UWB

Bluetooth

RFID

7. Automatic connections between what type of devices create a piconet?

VoIP

Bluetooth

Infrared

WirelessHD

8. In what type of wireless communication device will you find a repeater?

satellite

antenna

NFC

WNIC

9. What kind of network is built around the concept of low-power transmitters built on towers that can use the same radio frequency channel?

Wi-Fi 802.11 networks

UWB A/V networks

cellular telephone networks

GPS tracking networks

10. What type of cellular network uses 100 percent digital transmission for voice and data and can reach rates up to 150 Mbps?

CDMA

GSM

11. What kind of device does a WLAN use to facilitate communication between wireless computers?

Ethernet switch

access point

GPS hub

cell station

12. Which wireless standard provides for data transmission speeds up to 600 Mbps with a range up to 375 feet?

802.11g

802.16m

WiGig

802.11n

13. Which technology uses regular phone lines and transmits at speeds up to 256 Kbps?

POTS

ISDN

cable modem

14. Which communication technology should you use if you need to connect three offices which are all within 3 miles of each other at speeds up to 75 Mbps using antennas?

WiMax

DSL

ISDN

15. Where are you most likely to find the WAP2 protocol in use?

cellular phones

tablets

laptops

servers

16. What term refers to the combining of voice, video and text-processing and access to multiple network platforms from a single device?

access aggregation

digital convergence

digital landscape

network transparency

COMPLETION

1. Smartphones can use software that allow them to make ______________ phone calls over a wireless LAN instead of the cellular network.

2. Bluetooth communicates using small, low-power ______________ called radio modules.

3. In the future, most barcode functions are likely to be replaced by ___________ tags including for the purpose of inventory management.

4. To protect confidentiality, wireless data can be ______________ between the access point and wireless device, allowing only the recipient to decode the message.

5. The FCC, FDA, and EPA have established ________ exposure safety guidelines to limit the signal absorption rate of wireless device users.

MATCHING

motes

Bluetooth

DSL

UWB

J2ME

WiGig

link manager

WPAN

1. a wireless standard that enables devices to transmit data at up to 721.2 Kbps

over a typical maximum distance of 33 feet

2. a variation of the Java programming language designed for use in portable devices such as cellular phones

3. a very small network that typically extends to 10 meters or less

4. a technology used to transmit data over special telephone lines at 1.544 Mbps

5. an alliance of companies involved in developing a common wireless specification using the 60 GHz band

6. a technology used to transmit data over a telephone line

7. remote sensors used for collecting data from manufacturing equipment or for

scientific research

8. wireless communications technology that allows devices to transmit data at hundreds of megabits or even gigabits per second at short distances

9. a digital cellular technology that can send data at up to 21 Mbps over the cellular telephone network

10. special software in Bluetooth devices that helps identify other Bluetooth devices

SHORT ANSWER

1. Describe how RFID can enhance a family’s convenience in the kitchen.

2. Describe Bluetooth technology and how it can be used in a computing environment.

3. What is UWB and how might it be used in a home?

4. What is a piconet?

5. What does a repeater do in a satellite communication system?

6. How does a WLAN use an access point?

7. Describe a WMAN and discuss a technology a WMAN might use.

8. What is digital convergence and how might it affect how people use network devices?

9. Discuss the use of wireless technologies in home entertainment.

10. Discuss how radio signal interference can affect wireless devices.

Chapter 2 - Wireless Data Transmission

TRUE/FALSE

1. The ASCII code uses 16 bits to represent 128 different characters.

2. Infrared light interferes with radio signals but is not affected by radio signals.

3. The height of a radio wave is called the amplitude of the wave.

4. Spread-spectrum signals are more susceptible to outside interference than narrow-band transmissions.

5. Hopping codes used in FHSS transmissions are configured on the base station by the network administrator.

MULTIPLE CHOICE

1. Which of the following is true about wireless radio signal transmissions?

they travel at the speed of light

they travel as discrete particles

they require an atmosphere to move

they require visible light

2. Which of the following is NOT true about infrared light?

it can be used in directed transmissions

it is less susceptible to interference from visible light sources

it can be used in diffused transmissions

all infrared signals are invisible

3. Which of the following transmits a signal in an infrared device?

diffuser

detector

emitter

antenna

4. Which of the following is NOT a limitation of using infrared wireless systems?

they lack mobility

someone can eavesdrop from another room

they use a line-of-sight principle

diffused transmissions have a range of 50 feet

5. Which of the following is a good application for an infrared wireless system?

stream movies from a server

whole house wireless network

wireless outdoor speakers

data transfer between laptop and camera

6. Which best describes an analog signal?

it starts and stops

consists of discrete pulses

intensity varies and is continuous

Morse code is an example

7. What process must occur to transmit a digital signal over an analog medium?

modulation

decoding

decoupling

emitting

8. The distance between a point in one wave cycle and the same point in the next wave cycle is called which of the following?

amplitude

carrier

wavelength

frequency

9. The frequency of a wave is best defined as which of the following?

encoding of bits onto an analog wave

a carrier wave that has been modulated

the voltage difference between the peak and trough of the wave

the number of times a cycle occurs within one second

10. What is the unit of measurement for radio frequency?

volt

rpm

amp

11. What is the role of an antenna on a wireless device?

it receives data

it serves as a ground signal

it demodulates

it transmits and receives data

12. Which of the following is true about baud rate?

only one bit can be transferred per signal unit (baud)

a baud rate of 2400 always means a bandwidth of 2400 bps

multiple bits can be transferred with each signal unit

multiple signal units are needed to represent each bit

13. Which of the following best describes bandwidth in an analog system?

the range of frequencies that can be transmitted by a system

the number of bytes transmitted per minute

the number of bits transmitted per second

the maximum frequency supported by the medium

14. Which of the following is NOT a type of modulation that can be applied to an analog signal?

phase

frequency

carrier

amplitude

15. Which type of radio signal is most susceptible from interference sources such as lightning?

16. Which of the following is NOT an advantage of digital modulation over analog modulation?

better use of bandwidth

better performance during interference

requires less power

modulation techniques are simpler

17. Which binary signaling technique reduces the voltage to zero during the transmission of a 1 bit before the bit period ends.

NRZ-L

NRZ-I

NRZ

18. Which binary modulation technique employs NRZ coding such that the absence of a carrier signal represents a 0 bit?

ASK

FSK

BPSK

PSK

19. Which radio transmission method uses a chipping code?

DSSS

FHSS

20. Which of the following is a spread spectrum technique that employs mathematical algorithms to recover lost data bits?

frequency hopping

narrow band

direct sequence

wide band

COMPLETION

1. Data signals in a wireless communication system travel on _______________ waves.

2. A signal that is broadcast as a continuous wave is called a(n) _______________ signal.

3. When representing a wave with a garden hose, the distance between the peaks of the waves represents the ____________.

4. The _______________ non-return-to-zero encoding method represents a 1 bit by increasing voltage to a positive value and a 0 bit by decreasing the voltage to a negative value.

5. In the presence of background interference, receivers can detect a ____________ change more reliably than a frequency or amplitude change.

MATCHING

ASCII

digital modulation

amplitude modulation

frequency modulation

analog signal

hopping code

baud rate

NRZ

carrier signal

1. a method of encoding a digital signal onto an analog carrier wave for transmission over media that does not support direct digital signal transmission

2. the number of times that a carrier signal changes per second

3. a technique that changes the number of wave cycles in response to a change in the amplitude of the input signal

4. a binary signaling technique that increases the voltage to represent a 1 bit but provides no voltage for a 0 bit

5. a technique that changes the height of a carrier wave in response to a change in the height of the input signal

6. a signal of a particular frequency that is modulated to contain either analog or digital data

7. a technique that changes the starting point of a wave cycle in response to a change in the amplitude of the input signal

8. the sequence of changing frequencies used in FHSS

9. a coding scheme that uses the numbers from 0 to 127 to represent alphanumeric characters and symbols

10. a signal in which the intensity (amplitude or voltage) varies continuously and smoothly over a period of time

SHORT ANSWER

1. Describe the components in an infrared wireless system.

2. What are the advantages and limitations of an infrared wireless system?

3. Contrast analog signals with digital signals.

4. Describe how radio transmitters use a carrier signal.

5. How are radio waves transmitted using an antenna?

6. What are the three types of modulation that can be applied to an analog signal to enable it to carry information?

7. Describe amplitude modulation.

8. Describe the NRZ technique of representing bit signals.

9. What is phase shift keying? Describe how it works.

10. How are bits transmitted using DSSS? Include the chipping code in your answer.

Chapter 3 - Radio Frequency Communications

TRUE/FALSE

1. A high-pass filter allows all signals above a minimum threshold to pass through.

2. A mixer separates an input into two or more outputs.

3. TDMA was developed to overcome the problem of crosstalk.

4. A disadvantage of CDMA is that it can only carry one third the amount of data of TDMA.

5. There are no power limits imposed on devices using the unregulated bands.

MULTIPLE CHOICE

1. Which of the following is NOT a common component of all radio systems?

filter

mixer

emitter

antenna

2. Which of the following is a type of RF filter?

top-pass

bandpass

mid-pass

medipass

3. If a low-pass filter is set at 2200 MHz, which of the following signals would be allowed to pass through?

2400 MHz

1000 MHz

1500 GHz

23000 KHz

4. What kind of signals can result from the process of modulating a signal with data to be transmitted?

harmonics

modulators

passbands

sidebands

5. The sidebands of a frequency carrier are best described as which of the following?

the sum of the carrier signal and the highest value of the mixer output

the average of the high and low values of the input signal

the difference between the highest and lowest input frequency

the sum and difference of the highest input signal and carrier frequency

6. Which type of device is considered active device because it adds power to a signal?

mixer

antenna

filter

amplifier

7. Which of the following would take a transmission band of 1000 Hz and divide it into 100 channels of 10 Hz each to accommodate multiple access?

FDMA

CDMA

TDMA

SDMA

8. Which multiple access method overcomes the problem of crosstalk and divides the transmission time into several slots?

SDMA

TDMA

CDMA

FDMA

9. Which multiple access method uses a spreading code?

CDMA

SDMA

TDMA

FDMA

10. What type of transmission is a broadcast radio station an example of?

duplex

simplex

half-simplex

half-duplex

11. Which type of switching is used in a POTS system?

packet switching

cellular switching

circuit switching

frame switching

12. What can take place when signal strength falls close to or below the level of noise?

SNR

crosstalk

interference

attenuation

13. Objects in the path of a radio signal can cause which of the following?

crosstalk

EMI

amplification

attenuation

14. What is the term for signals that get reflected and travel different paths between transmitter and receiver arrive out of phase?

electro-magnetic interference

multipath distortion

reflective attenuation

phase misalignment

15. What problem can a directional antenna reduce in severity?

reflective attenuation

phase misalignment

multipath distortion

electro-magnetic interference

16. Which type of standard is an official standard controlled by and organization or body open to everyone?

de jure standards

consortia standards

de facto standards

paramount standards

17. Which standards organization functions as a clearinghouse for many types of standards development in the U.S.?

ETSI

ANSI

IETF

ISOC

18. Which standards body deals with user-premises equipment and satellite communications?

IAB

IETF

TIA

ISCO

19. Which international standards organization coordinates global communications networks and services and is actually a treaty organization?

IAB

ISO

TIA

ITU

20. In which frequency band will you find an 802.11 network?

medium frequency (MF)

extremely high frequency (EHF)

super high frequency (SHF)

very high frequency (VHF)

COMPLETION

1. A __________________ filter sets a range of frequencies that include a minimum and maximum threshold.

2. _________________ uses direct sequence spread spectrum technology.

3. ____________________ transmission is typically used in consumer devices such as CB radios or walkie talkies where you have to hold down a button while speaking.

4. A technique called ______________ array processing replaces a traditional antenna

5. _______________ transmission uses low-power, precisely timed pulses of energy that operate in the same frequency spectrum as low-end noise and is used in WiGig.

MATCHING

circuit switching

license exempt spectrum

directional antenna

packet switching

full-duplex transmission

signal-to-noise ratio

half-duplex transmission

simplex transmission

harmonics

switching

1. transmission that occurs in both directions but only one way at a time

2. a switching technique in which a dedicated and direct physical connection is made between two transmitting devices

3. transmission that occurs in only one direction

4. unregulated radio frequency bands that are available in the United States to any users without a license

5. transmissions in which data flows in either direction simultaneously

6. moving a signal from one wire or frequency to another

7. data transmission that is broken into smaller units

8. an antenna that radiates the electromagnetic waves in one direction only

9. stray oscillations that result from the process of modulating a wave and that

fall outside the range of frequencies used for transmission

10. the measure of signal strength relative to the background noise

SHORT ANSWER

1. What does a filter do and why is one needed in a radio system?

2. List the three types of RF filters.

3. Why are filters found in transmitters?

4. What is the purpose of a mixer? Include a discussion of sidebands in your answer.

5. What is an amplifier and why is it a crucial component in a radio system?

6. Describe time division multiple access.

7. What are two advantages that TDMA has over FDMA?

8. What are three advantages of CDMA over TDMA?

9. What advantages does packet switching have over circuit switching for transmitting data?

10. What is multipath distortion?

Chapter 4 - How Antennas Work

TRUE/FALSE

1. Cables and connectors offer resistance to the flow of electricity, increasing the power of a signal.

2. Decibels are an absolute measurement of signal strength, making it simpler to calculate gain or loss.

3. The size of an antenna is directly proportional to the wavelength of the signal it is designed to transmit and receive.

4. A monopole antenna is a type of two-dimensional antenna.

5. Point-to-point wireless links are best served by using omnidirectional antennas.

MULTIPLE CHOICE

1. Which of the following is likely to result in a wireless signal gain?

cables

connectors

amplifier

atmosphere

2. What unit of measurement is a ratio between two signal levels?

volt

decibel

watt

ohm

3. Which value indicates the signal being measured is twice the power?

+3 dB

+5 mW

-5 dB

-3 mW

4. If a signal is represented as 15 mW + 10 db, what is the resulting signal strength in mW?

30 mW

75 mW

25 mW

150 mW

5. Which of the following refers to the gain an antenna has over a dipole antenna at the same frequency?

dBm

dBi

dBd

dBg

6. Which of the following is true about antennas?

the size is proportional to the wavelength

most are active devices

lower frequency signals require larger antennas

omnidirectional types provide the best directional gain

7. Which of the following is true about omnidirectional antennas?

they work best in point-to-point links

longer ones usually have higher gain

they cannot be used in 802.11 applications

they emit a signal in three dimensions

8. Which type of directional antenna is used for outdoor applications up to 16 miles?

cellular

parabolic dish

patch

yagi

9. A cellular phone antenna that is 13 inches long would be considered which of the following?

eighth-wave

half-wave

quarter-wave

full-wave

10. If an antenna is much longer than the wavelength, what is the typical result?

inefficient delivery of RF energy

wrong signal frequency

signals that are an incorrect wavelength

no signal is transmitted

11. What does antenna polarization determine about the performance of the antenna?

radiation pattern

measurement of signals is positive or negative voltage

horizontal or vertical orientation

direction of the signal

12. What type of antenna is a straight piece of wire with no reflecting ground element?

monopole

horn

dipole

dish

13. Which type of antenna is two-dimensional, is common in telephone networks, and is used to transmit high-power microwave signals between towers?

patch

horn

satellite dish

dipole

14. What type of antenna is divided into a matrix of radiating elements and are used in modern radar systems?

switched beam

patch

horn

phased array

15. When a coaxial cable connects the antenna to the transmitter, what property of the cable must match that of the antenna?

impedance

length

thickness

inductance

16. What type of wave propagation do RF signals transmitted at 50 MHz have?

ground waves

line-of-sight waves

sky waves

atmospheric waves

17. Which type of antenna should usually be used at the central location in a point-to-multipoint wireless link?

unidirectional

directional

omnidirectional

semi-directional

18. Which of the following is the elliptical region within which signals travel between two antennas in a point-to-point link?

troposphere radius

Fresnel zone

propagation limit

wave pattern

19. What is the signal strength necessary to meet a receiver’s minimum requirements?

transmission path

minimum wavelength

Fresnel zone

link budget

20. What is the maximum percent of the Fresnel zone that can be blocked by obstructions in a point-to-point link?

20%

40%

60%

10%

COMPLETION

1. ______________ is the effect of an amplifier boosting the power of a signal.

2. A radio signal’s power does not change in a linear fashion, but instead changes ______________.

3. _____________ is a relative measurement used to represent gain or loss in a signal.

4. When considering antenna size, lower frequencies require ___________ antennas.

5. A _________________ analyzer is a tool that displays the signal amplitude and frequency of a radio transmission.

MATCHING

antenna pattern

ground-plane

dB isotropic

isotropic radiator

dBm

passive antenna

dipole

patch antenna

free space loss

smart antenna

1. the signal loss that occurs as a result of the tendency of RF waves to spread

2. a theoretically perfect sphere that radiates power equally in all directions

3. the relative measurement of the gain of an antenna when compared to a theoretical isotropic radiator

4. a new type of antenna that uses a signal processor and an array of narrow beam elements

5. a graphic that shows how a signal radiates out of an antenna

6. a semi-directional antenna that emits a wide horizontal beam and an even

wider vertical beam

7. a metal disc or two straight wires assembled at 90 degrees, used to provide

a reflection point for monopole antennas

8. a relative way to indicate an absolute power level in the linear watt scale

9. can only radiate a signal with the same amount of energy that appears at the antenna connector

10. an antenna that has a fixed amount of gain over that of an isotropic radiator

SHORT ANSWER

1. List three of the four aspects of RF signal transmission you need to know.

2. Describe the “tens and threes of RF mathematics”.

3. What is an isotropic radiator?

4. Describe directional gain and how it can be accomplished with a passive antenna.

5. What are two types of directional antenna? Describe them.

6. What is free space loss? Describe how it occurs.

7. How does the size of an antenna affect its ability to transmit and receive?

8. What does an antenna pattern show about the RF wave?

9. What does antenna polarization tell you about the antenna wave? How is it important for signal reception?

10. Give two examples of two-dimensional antennas. Describe them.

#CIS 513 Week 5 Midterm Exam – Strayer NEW

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certainheartrunaway · 5 years ago

Text

3 element 50MHz LFA-Q Super-Gainer Quad Style Yagi

Product Dimensions and Weight

Product Length: 25.0000M

Product Widtg: 1.0280M

A 3 element LFA-Q (Super-rigid Quad-style) Super-Light Quad Style Yagi for 50-50.5MHz

The LFA-Q Packs a bigger punch than a traditional Yagi with MUCH MORE GAIN per metre of boom

If it is GAIN you want from a small boom, this is the antenna for you! Wow, Super compact boom!!

Checkout the TX Factor online review! http://m0scu.uk/tx-factor-episode-7/

IDEAL PORTABLE OR SOTA USE!

Despite it’s rigidity, the LFA-Q is extremely light weight and this means even in strong winds, snow and ice the LFA-Q will hold its own.

Marine grade Stainless Steel Fittings

Original Stauff Insulation clamps

Mill finished boom and elements for highest levels of accuracy

For more information Email here

Performance

Gain: 8.82dBi @ 50.1MHz

F/B: 24.04dB @ 50.1MHz

Peak Gain: 8.9dBi

Gain 10m above ground: 14.36dBi

Peak F/B: 16.95dB

Power Rating: 5kw

SWR: Below 1.4.1 from 50MHz to 50.5MHz

Boom Length: 1.98m

Loop Height: 50cms

Weight: 3kg/8lbs

Safe Wind Speed: 210Kph/130Mph

Turning Radius: 1.69m/5.77ft

Vertical Stacking: 2.75m

Customer comment on the LFA-Q:

”Very nice…assembled and installed over the last two days – even though it arrived over night!

Performs extremely well – It replaced a MET 144 8T (remember them) that was about 20 years old – the gamma match had become unstable – suspect the trombone dielectric has aged/decayed.

This antenna has great FB like the MET but I think gain is very comparable and bandwidth far, far superior.

Thanks for the great service

Martin VE7MM/G4EZG”

Specification

£179.95 https://www.innovantennas.com

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from DXER ham radio news http://bit.ly/2KkNTNv via IFTTT

#IFTTT #DXER ham radio news

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