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Re: ATV on 434 MHz, Formerly: 70 cm band plan???



On Tue, 14 Dec 1999 JOppen6115@aol.com wrote:

> Southern California, most of the ATV repeaters have an input on 434 MHz and 
> have for years.  This is coordinated through the local frequency coordination 
> council. ....  Apparently the subject was studied 
> extensively and it was concluded, for reasons similar to those stated 
> previously here, that interference would be minimal.

True more or less for past satellite ops where most operators were using
their "OSCAR" arrays with at least 13 dB Beams to listen to the
satellites and looking up...  But at our TMARC meeting I pointed out two
new considerations:

1)  THe new Kenwood Mobile radio with built in 9600 baud TNC and front
panel packet (APRS/MESSAGE) display makes the receipt of messages by
mobiles directly from satellites a reality.

2)  We have demonstrated that this works, and the radio can receive at
least a few minutes of traffic on each overhead pass on a mobile whip
antenna.  But this is truely "weak signal" reception on a whip...

Thus, This capability will be useless within a few miles of any ATV
transmitter on 434.  BUT, ALSO CONSIDER... 

1)  that in Southern California, the entire basin is already covered by a
terrestrial APRS network so there is no need for a "satellite received"
message, when the same mobile can receive the same message on 144.39.

2)  Conversly, the fellow driving though the plains of Lenard Kansas who
does need to receive his trafffic via satelltie will probably NOT be
within a few miles of an ATV station transmitting on 434...

For what it's worth...  :-)  Bob, WB4APR


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