[aprssig] Lotsa ears, big mouth concept.

Lynn W. Deffenbaugh (Mr) ldeffenb at homeside.to
Mon Oct 12 12:19:01 EDT 2009

Wes Johnston, AI4PX wrote:
> Second, once a packet is transmitted from the main TX site, it will be 
> heard by all RX sites in the footprint.  How do we keep them from 
> sending the same packets back to the receive site in an infinite 
> loop?  Make the TX site transmit a PL tone (not 100hz).  Configure the 
> satellite recievers to hear everything (open squelch) and when the PL 
> tone is decoded in the audio we make a one-shot fire for just a few ms 
> to glich the audio.  This gliched audio prevents the TNCs at the 
> receive sites from decoding the packets because they will fail CRC... 
> therefore there is nothing to send to the main TX site.  The loop is 
> broken, which in this case is a good thing.
If the receiver sites know so much about the transmitter site, they can 
just ignore any packet with the TX site marked "used" in the path.  The 
transmitter IS inserting its call in the path, right?

Lynn (D) - KJ4ERJ

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