[sci.electronics] Low Power Television Transmitters

ron@vicorp.com (Ron Peterson) (06/19/91)

I've heard that recent legislation has made it legal to set up your own
low power television station without requiring a license or technical
degree in the operation of transmitters.  Does anyone know the details
like:
 - what's the max power allowed and what range can be reached with that power?
 - what frequencies can be used-VHF, UHF?
 - what does a minimal transmitter cost?  Anyone sell kits or plans for
     constructing your own?
 - are there any restrictions?  e.g., can the transmitter be mobile?  Is
     broadcast limited to one frequency or one locality?  Are there any 
     restrictions on programming material (sexual for example)?  Are
     regular daily broadcast times or 24 hour operation required?
     Can it be used for personal communication (like a video CB radio)?
 - If there are rules & regulations where do I call to get a copy of them?

ron@vicorp.com or uunet!vicorp!ron

ornitz@kodak.kodak.com (Barry Ornitz) (06/19/91)

In article <1991Jun18.193226.229@vicorp.com> the following questions are asked:
>
>I've heard that recent legislation has made it legal to set up your own

The legislation is not really that new - commercial products are.

>low power television station without requiring a license or technical
>degree in the operation of transmitters.  Does anyone know the details
>like:
> - what's the max power allowed and what range can be reached with that power?

Typical power is 100 milliwatts or less.  Range under optimum conditions is a
few hundred feet.

> - what frequencies can be used-VHF, UHF?

The most common frequency band is the 902-928 MHz band.

> - what does a minimal transmitter cost?  Anyone sell kits or plans for
>     constructing your own?

I have seen commercial units sell for as low as $30.

> - are there any restrictions?  e.g., can the transmitter be mobile?  Is
>     broadcast limited to one frequency or one locality?  Are there any 
>     restrictions on programming material (sexual for example)?  Are
>     regular daily broadcast times or 24 hour operation required?
>     Can it be used for personal communication (like a video CB radio)?
> - If there are rules & regulations where do I call to get a copy of them?

The band is shared with amateur radio operators, Industrial Scientific and
Medical equipment like diathermy machines and industrial microwave heaters, as
well as the government.  You must accept any interference from any licensed
user of the band.  Furthermore, your transmissions cannot interfere with
licensed users.  Hams are beginning to use these frequencies more often and
you will have no recourse but to accept the fact that your system will be
good for little more than sending your VCR signals to another room in your
house.

I see no reason why mobile operation would not be possible.  Sending out
offensive material might get you in trouble.  There are no time restraints.
I am not sure about personal communication since wireless microphones cannot
be used for two-way communication by law.  Unlicensed walkie-talkies use 
specific frequencies assigned for this purpose.

I would suggest you look into part 15 of the Federal Communications Commission
Rules & Regulations.  You can find these at your local library as part of the
Code of Federal Regulations.
					Barry


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|  ___  ________  |       Dr. Barry L. Ornitz          WA4VZQ
| |  / /        | |       Eastman Kodak Company
| | / /         | |       Eastman Chemical Company Research Laboratories
| |< < K O D A K| |       Process Instrumentation Research Laboratory
| | \ \         | |       P. O. Box 1972, Building 167B
| |__\ \________| |       Kingsport, TN  37662       615/229-4904
|                 |       INTERNET:   ornitz@kodak.com
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mcovingt@athena.cs.uga.edu (Michael A. Covington) (06/19/91)

Don't get too excited -- the range is about 30 feet.

Part 15 (low-power unlicensed transmitters) has recently been liberalized
to permit the use of very weak signals on almost any frequency.

Obscene or indecent transmissions are still illegal, although if the range
is not outside your house that's probably a moot point.
-- 
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Michael A. Covington | Artificial Intelligence Programs
The University of Georgia  |  Athens, GA 30602   U.S.A.
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