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[aprssig] Future APRS in every radio

Scott Miller scott at opentrac.org
Fri Mar 4 21:07:32 UTC 2005

> ALl of this can be done with a simple pic and no
> external GPS.  Nuttin.  Just the pic and a radio
> with control capability.
> The PIC just keeps an eye on the voice frequency
> in use and periodically when the user is not using
> the radio, does the QSY and transmission and
> returns..

There are some practical issues with this.  Even if you're sure that the
voice channel isn't currently in use, you've got to switch to 144.39
(probably causing the radio to beep), listen to see if it's busy, possibly
wait a while for the channel to be open, and while you're waiting, the
packet noise is going to be coming out the speaker at full volume.  I don't
know of any radio that offers a speaker mute on the mic connector.  And
since you've usually only got a channel-up and channel-down signal, it'd
only work properly for one channel setting.

So really, it'd only be practical on radios with a more intelligent
accessory connector.  The only ones I've worked with that have the necessary
signals are the commercial Kenwood series 90 rigs.  Do any ham rigs offer
that sort of connector, with audio in, audio out, speaker mute, and channel

I also don't like how vicinity tracking is handled by clients.  If I recall,
positions are just randomized based on the digi's position.  I think it'd be
better to have them appear somewhere OFF the map, maybe in a sidebar of
'stations in this area.'  Or have a 'heard stations' list for each digi.
Whatever.  Putting positions on the map when you only know where they are to
within a thousand square miles (< 18 mile radius) is misleading at best.


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