Path: utzoo!mnetor!uunet!husc6!hao!noao!mcdsun!nud!anasaz!john
From: john@anasaz.UUCP (John Moore)
Newsgroups: sci.electronics
Subject: Re: low power license free packet?
Message-ID: <696@anasaz.UUCP>
Date: 7 Mar 88 15:18:57 GMT
References: <17327@glacier.STANFORD.EDU> <1004@bcd-dyn.UUCP> <5607@cit-vax.Caltech.Edu> <4726@ecsvax.UUCP>
Reply-To: john@anasaz.UUCP (John Moore)
Organization: Anasazi Inc, Phoenix AZ
Lines: 23

In article <4726@ecsvax.UUCP> urjlew@ecsvax.UUCP (Rostyk Lewyckyj) writes:
>In article <5607@cit-vax.Caltech.Edu>, peting@cit-vax.Caltech.Edu (Mark Peting) writes:
>> One solution for providing a packet band without taking anyone's spectrum
>> is to allow the use of any unused UHF television channel in an area.
>> Even in large cities there are hundreds of megahertz available for this.
There is a company in California (I forget the name) that has a patented
system for doing this. However, they are careful to only transmit during
the horizontal and vertical blanking interval of the adjacent (if any) channel.
This protects receivers of that channel, which might otherwise show
interference.
	TV receivers are very sensitive detectors of interference. Signals
40 dB less than carrier power can be seen on the video quite easily. Also,
UHF TV receivers are not too selective - that's why the FCC keeps the
UHF stations 6 channels (36 MHZ) apart, wasting all that bandwidth in
the first place!



-- 
John Moore (NJ7E)   hao!noao!mcdsun!nud!anasaz!john
(602) 870-3330 (day or evening)
The opinions expressed here are obviously not mine, so they must be
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