[aprssig] Why do we not use APRS 9600?

Scott Miller scott at opentrac.org
Wed Feb 16 17:33:20 EST 2022

If I remember right they were HopeRF RFM23BPWs: 


On 2/16/2022 2:23 PM, DANA MYERS wrote:
>> On 02/16/2022 2:13 PM Scott Miller <scott at opentrac.org> wrote:
>> If you were going to build a whole new system from scratch and set 
>> some minimum requirements, 9600 baud would be a good idea.
>> Several years ago I built a batch of magnetic mount trackers for 
>> ambulances and support vehicles at Burning Man. We had two dozen 9600 
>> baud trackers on a single channel with a network cycle time of 6 
>> seconds, and each tracker transmitted every position packet twice for 
>> a total of 8 packets per second. They were all received by a single 
>> TM-D710. The transmitters were half-watt modules on the 70cm band and 
>> I think they were maybe $20 each. They worked well and we could track 
>> ambulances until they disappeared into the hills about 15 miles away 
>> on their way to Reno.
>> Higher power radios tend to not have such a fast TXD though. 
> Were these modules crystal-controlled? The fastest TxD radios (20mS 
> and less)
> I've had are all crystal-controlled, with the lone exception of an 
> MCX-100 with
> Fast-Lok synthesizer option, that was as fast as crystal-controlled.
> 73,
> Dana  K6JQ
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