[aprssig] TWO-WAY trackers!

Bob Bruninga bruninga at usna.edu
Sat Sep 22 09:59:49 CDT 2007

> Oh no, not another deaf tracker.....

Actually, the capability is there for us to be able to  close the loop with two-way communications to mobiles that only have one-way APRS devices.  Here's how.

The new APRS FREQUENCY initiative, has created a standard for including OPERATING frequency in every position report.  This allows a one-way APRS device to report its "talk-back frequency".

Since these trackers are usually connected to a 2m radio, and the RECEIVER of that radio is not doing anything else, Then it should be tuned to a special call-back frequency.  Probably APRS voice alert just like all the mobile Kenwoods too.  That way at least that tracker driver can be contacted.

That is what APRS is all about.  Facilitating communications in the local area about all-things-ham-radio.  My suggestion is as follows:

* Trackers turn up the volume of their receivers.
* Set the radio to 144.39 (in the USA)
* Set CTCSS 100 Hz
* Set your Tracker position text to be:

144.390MHz T100 Joe

This then not only puts you on the map everywhere you go, but also makes it possible for people to include you in what is going on and be able to chat APRS...

ALso, you could set the radio to split frequency and monitor 146.52 instead.  In that case, unless you always like to monitor that channel, I suggest you set CTCSS to SOME OTHER TONE so that you can still always be contacted, but you dont have to listen to noise all the time when you are near interferrence.  The DANGER of noise, is that it tends to encourage one to turn the volume down (and then forget that it is down).  Then you are off the air, and that is NOT good, when you are advertising you are LISTENING, but not.

You must set a DIFFERENT CTCSS if you are going to operate with split receive beacause you are still Transmitting APRS on 144.39.  And the LAST thing we want to hear is PL 100 packets on .39 with someone NOT then LISTENING...


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