Plug and Play
Manuals & Repairs
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video overlay
Transmitting ATV
Receiving ATV
Legal Uses
ATV DX ATV DX records
Ham TV Application Notes
By Tom O'Hara, W6ORG, retired owner of P. C. Electronics,
the Leader in Amateur Television Equipment for 50 years - History

tower cam

ATV Repeater
Live Tower Cam ID

Feb. 17, 2023

On this page, scroll down or click on the subject headings:

ATV Application Notes-lots of fun stuff & how to do it.
    Other ATV technical information and sources
       ATV clubs and groups
           Other ATV manufacturers and parts sources
               Getting a Ham License, update and renewals
                    Legal uses of Ham Radio & FCC Rules
                        License Free and Government Use.

ATV Application Notes
Scroll down
Most of these app notes are down loadable as pdf files and can be opened, read and printed with Adobe Acrobat Reader - You can download a free copy of Acrobat Reader from Adobe.

ATV DX variables - Public Service, ARES/RACES - Portable Repeater - Helmet Cam - 5W TX construction - Repeater Design - Rocket - Balloon - R/C Vehicles - Real Aircraft - CH 3 to A/V receiver - Amplifier Set Up - Homebrew Antennas and more.

    ATV, Where To Start - Download the App Note
    A beginners guide to seeing your first ATV picture. It's easy and surprisingly, low cost. Seeing your first ATV picture may be free if you have a TV with a cable TV tuner in it. Even new cable ready digital TV's are required by FCC Rule 15.118(b) to have analog NTSC cable channels in them also. Cable channels 57 to 60 are the same frequency as the most popular 70cm ATV band, 420-450 MHz. If there is an ATV repeater or close by ATVer in your area, you might see something by connecting your cable ready TV to a 70cm antenna on the roof, then calling "CQ ATV" on 144.34 or 146.43 simplex, the most used 2 meter FM voice, ATV "talk back" frequencies. See ATV clubs and the ARRL Repeater Directory.
    Upon request, we can modify these two ATV, Where To Start pages free to you in pdf format with your local ATV information put in so you can make copies for handouts at your radio club meeting or add to your clubs web site.
    ATV DX Variables - App Note
    What kind of line of sight distance can be expected with ATV?
    Given various transmitter power levels and antenna gains this app note will tell you.
    Basically antenna placement and gain are the most important parts of the ATV system. Non line of sight paths over the RF horizon or through obstructions are not predictable, best to try it out by seeing how you do on 2 meter voice as an indicator of possibility.
    ATV for EmComm and Public Service Events - App Note
    ARES, RACES Homeland Security, radio clubs and emergency service organizations are given basic info in this app note for the unique use of ATV in their operations. ATV is a great visual aid for command and control and for remote damage assessment transmitting back to an Emergency Operations Center (EOC).
    For most incidents within a 15 mile line of sight radius, we suggest starting out running simplex on 70cm with the Videolynx VM70X transmitter module or TX70-5s ready to go >4W transmitter connected to a color camera for mobile / portable transmission, and an Arrow 440-5S antenna. At the EOC or receive end another 5L-70cm beam or Diamond X510N(x) vertical onmi to a TVC-4S downconverter and TV set. In a pinch, you can place any television set to cable channels 57-60 to receive the video at other locations as necessary if close enough. If you prefer Audio and Video (A/V) outputs to drive a monitor at the EOC or a camcorder monitor in the field, add the Rch3 channel 3 receiver to the TVC-4S downconverter. You can also receive the 70cm ham band with a cable TV tuner to USB box connected to a MAC or PC lap top or desk computer.
    For short distances transmitting portable back to an Emergency Communications Van we suggest the Videolynx 434 or Z70A 50-100 mw transmitter for up to 1/4 mile, or the Videolynx VM70X for up to a mile or more - See the ATV DX graph and the examples, ATV Belt Pouch and Hat Cam app notes.
    Shown right is the 70cm video transmitted from the W6ORG motorcycle ATV mobile back to the command post televising police response to a medical emergency incident that was holding up passage of floats during the Pasadena CA New Years Day Rose Parade. Check out page 40 in KA6UTC's Rose Parade Tech Notes. There are many similar public service events or actual emergency incidents that can benefit from live video. We get snow free video and audio running 1W and 5 element beams between aid stations 6 miles line of sight at the Angeles Crest 100 mile trail race. See the KE3GG's video of ATV at a charity run/walk aid station
    Portable Public Service ATV
- App Note
    This simple "Milk Crate" ATV crossband repeater is a great Go Kit for getting ATV over hills, buildings or other obsticles when you don't have line of sight simplex to the EOC. The Milk Crate ATV system is easy to transport by car or helicopter and quick to set up. Place on a building above an incident site to retransmit ATV from your Hard Hat Cam. Use it in repeat mode, simplex, beacon or even full ATV duplex between two locations with a second system using the opposite cross bands for input and output. ID is automatic with the built in OSD board in the repeater controller so you can concentrate on the incident and not having to remember to ID every 10 minutes. 70cm in and 23cm out is shown, but other combinations of input and output bands could be used depending on harmonic relationships. Rather than building the ATV Go Kit in a milk crate, consider using a Pack N Roll like AC6Y did. See how two milk crates are used in duplex mode between remote aid stations at the Angeles Crest 100 Mile Trail Race.
    ATV Hard Hat Cam - App Note
    Build into a Hard Hat an ATV transmitter and color camera intended primarily for public service events but great for giving ATV demo's or showing others exactly what you are seeing too. If actually used at an incident requiring a hard hat, the system can be mounted in a belt pouch with antenna clipped to the outside of the hard hat.
    The project uses the Videolynx 434 video transmitter, mini color camera and 9V alkaline battery - it can run for about an hour on a single or 3 hours with 2 batteries.
    The Z70A 4 channel transmitter can add sound with the video and can also be used with the addition of another 9V battery in parallel. The Z70A is also popular in R/C robots.
    The Downeast Microwave 7025PA amp can be added to the Videolynx 434 or Z70A for higher power and home station use or package your own 25W amp using a RA30H4047M power module and our PA5 board.
    ATV in Radio Controlled
    - R/C - Vehicles
- App Note
    Special considerations are given for optimizing DX in R/C vehicles like building a vertical Dipole antenna for model aircraft and a Ground Plane for receiving in the app note. There are also shielding techniques, FCC Rules and IDing.
    The simplest system for getting about a 1/2 mile radius line of sight around a flying field is to mount a mini color camera, Videolynx 434 transmitter, Diamond RH3 antenna and 9V Alkaline battery like we did in the R/C helicopter - it adds just 7 oz in weight. If you run the Videolynx Z70A and 2nd 9V battery, the total is 11 oz.
    Best DX is on the 70cm band using a cable ready TV or a TV tuner to USB box with a lap top computer.
    1 Watt with a Videolynx VM70X transmitter module is good for 5 miles or more line of sight.
    Put a OSD-GPS+ board plus GPS receiver to overlay altitude, speed, heading, lat - lon., time and call ID on the video if you want to get fancy. However something with your call in view of the camera is the simplest. See FCC Rule 97.215.

See Larry Mitschke N5LND's video on his history experimenting and designing R/C aircraft with ATV.

    ATV in Aircraft - App Note
    Considerations for installing and flying ATV in helicopters and airplanes. Besides the fun of letting other hams fly along with you in hang gliders and aircraft, many emergency ham communications groups put ATV in local government helicopters for an eye in the sky as part of their ARES or RACES communications system.
    Pix at far right is our first experience putting ATV in a Los Angeles County Sheriffs Bell 47 helicopter in 1968 for the New Years day Rose Parade in Pasadena CA - see ARRL QST magazine May 1968 page 106 and page 40 in KA6UTC's Rose Parade Tech Notes. Also see May 2006 page 28 QST on a Go Kit by AC6Y for the Corona California PD helicopter.
    R/C Blimp ATV - App Note
    Great for flying around inside a ham convention hall or Boy Scout Jamboree to demonstrate ATV.
    However, different from N8UDK and N8QPJ's system on their web site, we suggest using the Videolynx 434 ATV transmitter, mini color camera running off of a 9V alkaline battery which makes a high performance but light package. Antennas are an easily made upside down ground plane on the blimp and another ground plane at the receiver.
    High Altitude Balloon ATV - App Note
    Some have flown higher than 100,000 feet and sent back video at the edge of space. We suggest using the Videolynx VM-70X transmitter module and an analog mini camera from ATV Research. The up to 5W VM-70X requires heat sinking and testing to make sure the mounting plate does not exceed 149F. A 50K thermistor can be added to the RF Power adjust trace for over temperature protection, and the module mounted to a heat sink or copper sheet placed in a hole in the styrofoam to conduct some of the heat outside. However, some heat inside is desireable at high altitude. Depending on the antenna polarity used in your area we suggest hanging an upside down vertical ground plane or horizontal W6OAL Little Wheel antenna below the balloon - See page 2 of our ATV in Amateur Rockets and Balloons application note or build your own. Receive with a TV on cable channels 58-60 or with a TVC-4S downconverter connected to a TV and an Arrow 440-5S beam, or Little Wheel plus reflector antenna.
    You can add a GPS receiver and the OSD-GPS+w/c board to overlay the balloons location, speed, altitude and also distance and bearing to the launch point. APRS or other sensor data packets can also be sent on the ATV sound subcarrier instead of audio. Some add a APRS packet transmitter on 144.39 and track using Google Map APRS on the internet.
    Multiple 1 Watt TXA5-RC series transmitters and Little Wheel antennas have even flown on NASA/JPL balloon experiments as part of a Mars program with good video received out over 50 miles distance and from 100,000 feet to splash down using a TV and small beam to receive.
    The EOSS - Edge Of Space Sciences - web site has a lot of info, sources and links to balloon groups
    Bill Brown, WB8ELK, is the guru for ATV balloon flights and has made a number of videos. See an interview of Bill on starting about minute 9. He has an over 30 year record of balloon flights including us in a helicopter finding his first live video balloon in the Mojave Desert in 1989 and Angry Birds in Near Space".
    Balloon Launch announcements can be found on the ARHAB web site. There might be a launch near you - if you are within a few hundred miles, monitor the frequencies given and you might see the edge of space.
    Check out the video of an ATV Balloon flight - BLT-22 by K5SAF and some great pix of the BLT-24 flight by the South Texas Balloon Launch Team.
    FAA Rule 14 CFR 101 covers the regulations, limitations and requirements to fly balloons, rockets and kites in the USA.
    Near Space Ventures has a web based balloon flight path prediction system. Lots of good info on the Pico Balloons on the Northern Illinois Bottlecap Balloon Brigade web site.

balloon camera at 80,000 miles

At right ascending Mabel-1 balloon with ATV launched by Phil W8IC, Jeff N8QPJ and Chris N8UDK. Small tethered balloons with ATV can be fun at hamfests too using a mini color camera, Videolynx 434 transmitter, 70cm HT antenna and 9V Alkaline battery.

    ATV Antennas in Amateur Rockets and Balloons - App Note
    Rockets, Balloons or transmitting from any type of vehicle over head presents unique antenna problems for getting the best picture over the farthest distance on the horizon or at the launch site below.
    The type and placing of antennas in the vehicle and on the ground are discussed. Construction of a Turnstyle circular polarized antenna for launch site reception is described as well as making a reflector for the popular W6OAL Wheel horizontal omni antenna.
    We suggest our TXA5-RC series 1Watt transmitter board or Videolynx VM70X transmitter module for most rocket and balloon applications.
    See WC6P's video from a 7.5 inch dia rocket using one.
    Check out KD7JVF's video from his rocket glider.
    Homebrew Antennas - low cost and easy to make
    The Quagi antenna by Wayne N6NB is made from 12 gage copper TW house wire and wooden boom - 8 and 15 element beams for 70 and 23cm ATV. Another cheap and easy beam to build is by Kent WA5VJB. It is not as broad banded as the Quagi but fine if you prune it for your specific ATV frequency. Many bands and element lengths are shown.
    A simple omni directional vertical antenna for demo's, R/C receive, etc., is the ground plane antenna made with just a connector and some wire.
    The blanking pedestal in the ATV transmitters video modulator must be set to restore the video to sync ratio in Amateur linear amps to compensate for the gain compression which occurs typically between 1/2 to full rated peak envelope power rating of the amp. This app note gives you the procedure, why's and where fores. Average reading vs. Peak Envelope Power (PEP) RF meter readings are discussed.
    You can download more specific information on the 70cm Mirage D1010 / D100, D26N, RF Concepts/Kantronics RFC4-110 and Teletec DXP-U150 Amplifiers which describes the ATV version of these 70cm 150, 100 and 50 Watt amps, and what is done to make them ATV compatible.
    You can also down load our notes on driving the Downeast Microwave 7025PA 35 Watt 70cm, 70225PA 225 Watt 70cm and 2330PA 30 Watt 23cm amplifiers, also our PA5 board using the RA30H4047M RF power module for 25W on 70cm.
    Packaging the Videolynx VM-70X 5
    Watt transmitter module
- App Note
VM-70X ATV Transmitter packaged transmitter with VM-70X module
    The Videolynx VM-70X is a compact transmitter module that accepts line level audio and video, 11 to 14Vdc and has adjustable RF output from 0 to 5 Watts on 4 digiswitch selectalbe frequencies - 426.25, 427.25, 434.0 and 439.25 MHz. This app note describes adding a computer fan for R/C, robot, rocket or balloon applications and also for home or portable use, packaging the VM-70X along with the TR-1b T/R relay boards in a Hammond 1590D (7.4x4.7x2.1") diecast aluminum box. Estimated cost of all parts is about $300 in the App Note parts list on page 3.
    ATV Repeater System Design - App Note
ATV Repeater block diagram
    A must read before you start building an ATV Repeater including sample priced out parts list and sources depending whether you want to go inband or crossband, which band or bands you want to use, single broadband or multiband or 2 antennas, horizontal or vertical, etc.
    Inband ATV repeater example and parts list.
    Crossband ATV repeater example and parts list.
    Compare the attenuation curves of using an 8 pole or 10 pole VSB Filter especially on a 421.25 MHz repeater output.
    To figure the ATV repeater coverage area, click on ATV DX which is on our home page.
    Video Operated Relay - App Note
    The VOR-3 board has many uses - simple ATV repeater controller, beacon timer, 10 minute ID timer, video squelch, link vs. local priority switch, repeater voting, etc.
    Channel 3 TV receiver module modifications for ATV - App Note
    The Rch3 receiver - MCM Electronics Model 33-2060 - gives you a video and line audio output when connected to one of our 70cm downconverters like the TVC-4S. Great for seeing ATV on a camcorder monitor or DVD player screen when mobile or portable. The unit comes with a wall plug power supply for AC operation but this app note shows how to modify the receiver 16Vac input for 12 to 14 vdc input, add squelch and an S-meter.
    Antenna Mounting ATV Downconverters - App Note
    How to repackage a downconverter and the pluses and minuses of doing so vs. an antenna mounted preamp to eliminate the loss from long coax runs for optimum receive DX. For antenna mounted preamps you can make a bias T to power up the coax.
    Variable Tuning the TVC-xS Downconverters - App Note
    This app note describes how to add variable tuning to the synthesized TVCX-xS series of ATV downconverter boards used in our TVC-4S, 9S and 12S downconverters to enable tuning non-standard ATV frequencies in the band or fine tuning for sync bars in the noise when looking for DX.
    Gunnplexer ATV - App Note
    10 gHz Gunnplexer ATV transmitting system construction using the GVM-1 video modulator board. Wideband FM video modulation is used along with 6.2 and/or 6.8 MHz sound so that C band satellite TV receivers can be used along with a LNB made for 10.4 GHz. Gunnplexers are available from SHF Microwave and Advanced Receiver Research. Choose those that have varicap tuning diodes in them - the modulator connects to the varicap to FM modulate the Gunn diode in the Gunnplexer.
    70cm Band Planning - App Note
    434.0 vs 439.25 MHz LVSB technical considerations when FM voice repeaters expand below 444.0 MHz and coming up with an all mode local 70cm band plan. Lots of good information for frequency coordinators, repeater owners and any mode experiencing interference in the 70cm band because there is no sound technical band plan in place. Basically there is plenty of room in the 420-450 MHz band for FM voice repeaters and links, 2 ATV channels, weak signal, satellite and digital modes if a technical band plan is devised and agreed to by the areas hams.
    AM ATV DSB vs. VSB - App Note
    Describes the characteristics of transmitting AM video with double sidebands and vestigial sidebands, difficulty of maintaining VSB when driving amateur amps, and interference potential to other mode users.
    ATV Emission Characteristics - App Note
    A bunch of technical stuff including ATV emission bandwidth, channel spacing, sharing with other modes, and more.
    FM ATV - App Note
    Discusses differences between AM and FM transmission of ATV: DX, common frequencies, resolution, pre-emphasis / de-emphasis networks, etc. The ARRL 23cm bandplan does not have FM ATV. Here is a modified 23cm band plan that includes FM ATV.

Crystals Got an old transmitter or downconverter that you think the crystal went bad? Before you order a new rock, check out these trouble shooting tips. Also see our list of surplus crystals for $5 and sources for new crystals.

Ten pin VHS camera connector pin outs and connector source.

DC power connector pinouts and source for P. C. Electronics transceivers and transmitters.

Lamp replacement sources for P. C. Electronics Transceiver and Downconverters.

Manuals and Data Sheets on P. C. Electronics manufactured products are available by email request free only to licensed hams upon email request - include your call letters - model number with revision letter or year as etched on the board. Please request only 1 or 2 at a time.

Other ATV Info Sources:
    ARRL Radio Amateurs Handbook The best discussion of ATV starts in chapter 9,12 or 32 in older books, and in the Image Communications section of the Downloadable Suppliment or CD that comes with the 2014 book and beyond. This is the Radio Amateurs bible for all the many facets of the hobby. The ARRL Operating Manual also has a good section on Image Communications including ATV.
    Ham Nation is a weekly internet show with many different amateur radio topics including ATV - see episode 12 starting around minute 21.

Other ATV group web pages to check out:

    Southern California ATV Repeater Map (updated March 2021). In southern California, we suggest first getting a downconverter and antenna for the repeater ham band you are line of sight to and then seeing if you want to transmit later. You can talk back to the ATV transmitting stations on 146.430 (100.0 Hz) FM voice simplex. EmComm and public service groups use 426.25 MHz ATV simplex.
    The So. Calif. Microwave Experimentors net is on Monday nights 7:30 PM utilizing a 10 gHz to 3.3 gHz ATV repeater system on two mountain tops - Santiago and Heaps Peak with tower cam ID's. Also there is info on R/C and Rocket ATV. The San Bernardino Microwave Society (SBMS) meetings are televised by W6KVC on the 1st Thursdays of the month starting at 7pm and can be seen on most So. Calif. ATV repeaters.
    The ATN Amateur Television Network Net is on Tuesdays 7:30 PM. ATN has linked repeaters between the Los Angeles/ Orange/ San Bernardino/ Riverside County areas to Las Vegas, Santa Barbara and San Diego with the hub on Santiago Peak. Use 100.0 Hz CTCSS on 146.430 simplex to talk back through the Santiago Peak ATV repeater sound subcarrier output. W6ATV Rpt live stream

Manufacturers and dealers of ATV related equipment that we maintain a *web page for or recommend:

    *Intuitive Circuits - OSD Video ID overlay, ATV repeater
        controller & DTMF relay boards
    *Videolynx - 50mW & 5W 70cm AM ATV transmitter modules
    KH6HTV Video - wide range of ATV gear and app notes, especially on DVB-T.
    Hi-Des - DVB-T modulators and receivers
    DATV-Express - Fully assembled digital ATV exciter board. 100-2450 MHz.
    ATV Research - a great low cost source for small cameras
        and accessories
    Arrow Antenna - Antennas
    Directive Systems - Antennas and feeds
    Downeast Microwave - Amps and Preamps
    W6PQL - Linear amps and more.
    SHF Microwave - 10 gHz Gunnplexer source for ATV
    RF Parts - Diamond Antennas, replacement RF semiconductors and power modules
    DCI - VSB and bandpass filters
    Elktronics - Custom color video ID and grpahics VDG-1 generator board example at right.
    Hamcity - Store with all the major ham radio
        equipment brands in Culver City CA
    Ham Radio Outlet - Major ham radio equipment dealer with
        many stores around the country.
    Mouser Electronics - Big Catalogue of new Electronic Parts
    Digikey - Big Catalogue of new Electronic Parts
    Jameco - Big Catalogue of surplus and new Electronic Parts
    Marlin P. Jones - Big Catalogue of surplus and new Electronic Parts

Other Ham Radio resources:

    SSTV - KB4YZ's complete list of all things Slow Scan. SSTV allows still frame pictures over
        any voice mode channel.
    Ham Radio Online
    WA7RHK's Galaxy - over 300 ham manufacturers, dealers, and organizations
    DXzone - listing of Ham Radio links
    Open repeater listings - VHF&UHF in the USA
    QRZ Call sign lookup and Ham Radio Super Site

Getting a ham license

    You too can enjoy ATV and the many modes of radio communications open to you with an Amateur Radio license by first taking the FCC test for the code-free Technician Class Amateur Radio License. The entry level Technician Class FCC Amateur Radio license is all you need. A ham license is good for 10 years and is renewable on line at no cost or retest. There are 35 multiple choice questions from a pool of 429 of which you can miss no more than 7 to pass and learning morse code is no longer required. Cost of the initial test is about $10.

    The easiest, and takes the least time, is an one day class and test that is given 4 times a year - mid January, April, July and October - from 9am to 4pm on Sundays. Location is at the Agoura Hills Calabasas Community Center, 27040 Malibu Hills Road Calabasas, CA 91301, however, during the pandemic, they are doing it on Zoom. Cost is $75 and requires some pre-study. They use the "read only the right answers" method for passing a multiple guess type of test and have a 97% pass rate. After you get your license, you can learn what you need for the kind of operating you want to do. They have follow on classes.

    You can self study the right questions only method in your own time, then take the exam on line for $10. HamStudy has a study class for about $30 and they suggest averaging 1 hr per day for two weeks. If you prefer reading from a book rather than on the computer, you can get the Easy Way Tech class ham study book. Another on line study course is Ham Radio Prep - try it free for 5 minutes. The Gordon West Radio School has a variety of study books and tapes.
    It is important for hams to keep the FCC license data base current with your mailing address. If the FCC should happen to send you a piece of mail and it bounces back to them, they can revoke your license per 97.23. It has been estimated that about 20% of the addresses in the Callbook have changed. I have noted about the same when checking mailing addresses vs the Callbook. I dont think anyone would want to find upon renewal that their license was revoked and have to take the test over again.
    The easiest way to check, renew or update your license is on the QRZ/W5YI VEC web site.

Legal Uses of Amateur Radio and FCC Rules

    Amateur Radio and Television is legal only for non-commercial communications between licensed ham operators - FCC Rule 97.1. The purpose of Amateur Radio is a hobby that promotes the advancement of the radio art, international goodwill but most importantly, emergency communications. There are many fun applications of the ATV mode of this hobby which are described elsewhere scrolling on this page and on the home page.
    The FCC (Federal Communications Commission) regulates the use of the radio frequency spectrum so that communication services do not interfere with each other. FCC Rules, 47 CFR 97.111 and 97.113, prohibits Amateur Radio Service bands to be used, with very few exceptions, for one way transmissions or to further any business purpose - profit or non-profit - no broadcasting, news gathering, local cable access link, teaching aid for unrelated subjects, retransmitting any other service or music, private, home or business surveillance, or regular business of police, fire or government agencies except as allowed for occasional emergency preparedness drills operated by licensed hams or under FCC Rules 47 CFR part 97.407. The FCC recently defined a change to 97.113 that allows training for emergency communications using amateur radio by businesses such as hospitals and others in specific instances. State and local emergency service groups can operate under 97.407, Radio Amateur Civil Emergency Service, if they follow the outline as described by FEMA. Hams must identify their transmissions with their call letters at least every 10 minutes and at the end of a transmission - 97.119. One way transmission on Ham radio frequencies can be used for Radio Control vehicles without IDing and with some restrictions per 97.215. Penalties are up to $10,000 per day of illegal operation and 6 months in jail. For a complete list of all the Amateur Radio Service FCC Rules go to: FCC Part 97

License Free Part 15 and Business/Public Safety Part 90 Applications

    For short distance line of sight non-amateur video link applications up to 1000 feet, we suggest the legal Part 15 FCC Compliant license free wireless audio/video send and receive systems offered by Radio Shack (15-126) and others in the 902-928 MHz and 2.4 gHz bands. A transmitter and receiver system is typically about $100. Only the legal license free devices will all have an FCC ID sticker somewhere on them - any RF device that doesn't, and claims to be license free, probably is not legal. You are free to transmit audio and video for any purpose, business or personal at any time and for as long as you like. The key to getting the best distance is to position the attached antennas to point at each other and to have line of sight between them. The pop up paddle type of antennas often used on the Radio Shack or Wavecom wireless transmitters and receivers are somewhat directional perpendicular to their surface. One just has to move each end around to find the best spot and angle. You cannot legally detach and change the antennas or modify the devices in any way to increase the distance.
    Longer distance Business or Public Safety applications (ie. state and local police and fire departments) must use Part 90 FCC Compliant equipment and licensing. Some good sources of equipment and help with licensing are ATV Research (800-392-3922) or Microtek (888-366-4276). Part 90 frequencies wide enough to support video start at 2.0 gHz. Local law enforcement risks having evidence obtained by illegally using amateur radio frequencies or non FCC Compliant equipment and licensing thrown out of court as well as Federal fines and confiscation of the equipment.
    If both ends have access to the Web there are Web based real time video systems that offer the added feature of remote control and multiple cameras. This is much easier than a RF transmission system in both cost, unlimited distance and no license required. Check out the X10 Vanguard System as an example.
    Dont be fooled by ads for video transmitters that want you to believe that 10 to 100 milliwatts on 433 MHz or higher ham bands, cable channels 57 to 60 or TV broadcast channels are license free - they are not. You will interfere with and be seen by local hams and reported to the FCC. The FCC license free Part 15.209(a) limit for intentional radiators of 200 microvolts per meter measured at 3 meters works out to be less than 50 microwatts to a zero dB gain antenna in the 420-450 MHz Amateur Radio band and gives a distance of only about 30 feet. No amount of power can legally be intentionally transmitted on broadcast TV channels in the USA plus specific frequencies listed in 15.205.
    There are specific bands above 902 MHz set aside for higher power analog video license free devices in Part 15.249 that allow a maximum of 50,000 microvolts per meter radiated power measured at 3 meters which works out to just under 1 milliwatt to a dipole antenna. Depending on line of sight and antennas supplied, the distance can be up to 1000 feet with good video similar to what you would record on your VCR. However, one exception to the license free FCC Rules are Spread Spectrum digital devices can run up to 1 watt per Part 15.247. While these digital and spread spectrum RF devices can go for much greater distance than the analog ones under 15.249, the narrow modulated bandwidth and data rate if used for video would give reduced quality similar to internet video received with a 56 kbd dialup modem.

ISM Bands

    So called ISM (Industrial, Scientific and Medical) band devices must be FCC Certified under Part 18 of the FCC Rules and cannot be used for any telecommunications purpose (18.107(c)). Part 18.305(b) has very low radiation limits. ISM bands are for devices that use RF such as Microwave ovens, diathermy machines, etc., and not for voice, digital, video or any other mode of communications.

FCC ID Sticker and Marketing

    License free Part 15, ISM Part 18 and business Part 90 transmitting devices must pass FCC Compliance (per FCC Rule Part 2) plus have an FCC ID numbered sticker (15.19) on the device to be legally sold or even offered for sale. FCC Part 2.803 says that no one may offer for sale any RF device for a service that requires FCC Compliance without first getting FCC Compliance. Basically, if the RF device does not have a valid FCC ID sticker on it, it is probably illegal. You can verify that the FCC ID sticker number is for your specific RF device by going to the FCC Equipment Authorization web page, then click on FCC ID Search in the EA Related Databases on the left. Fill in the upper two blanks and hit return. There have been some companies who get a FCC ID for one device and put it on other products illegally. The FCC publishes a list of those they have found in violation on their Field Notices web page - for example, see on 05-17-2006, MCM and on 02-24-2006 2by2Security who were cited for marketing non FCC compliant RF devices and on 09-20-2012 the city of Redondo Beach for operating an illegal transmitter.

Federal Government Video Use

    U. S. Federal government agencies and their contractors must coordinate with IRAC (Interdepartment Radio Advisory Committee) in the Office of Spectrum Management of the NTIA (National Telecommunications & Information Administration) by frequency and location before operation. Area coordinators you can contact are listed in the downloadable Manual of Spectrum Rules and Regulations. Generally, frequencies within the ham bands will not be authorized due to high interference potential, but there are video frequencies set aside elsewhere for specific uses by area. If you do get an IRAC coordination within an Amateur Radio Service band, we strongly suggest you check the ARRL Repeater Directory and also contact your areas Amateur Radio Frequency Coordinator to make sure there is not a ham repeater or other users there.
    The complete FCC Rules can be found in text and pdf form at: 47CFRxxx. Check there for the latest updated versions of the FCC Rules noted above.

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