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[aprssig] Group Tracker Build Projects ?

Robert Bruninga bruninga at usna.edu
Thu Sep 22 22:01:10 UTC 2005


>Does anyone know of groups that have built 
>several trackers for... use during events?

No, but here is a Pocket Tracker Tip I tested
yesterday with success...

I discovered a neat way to use your car D700 as
a digi for your pocket tracker without QRM.

Set your pocket tracker on 144.99 (.39 +600) and
then put 144.99 in your D700 CALL channel.  Then 
set the A band to scan between CALL and 144.39.  
The D700 scans very rapidly between the two.

This way, your pocket tracker (if it has a long enough
TXD) can get into your D700 without any QRM 
interference from other traffic on the APRS channel
yet, your D700 will be monitoring both and will
hold off digipeating you back to the APRS channel
until the channel clears.

THIS NEEDS MORE TESTING HOWEVER, SO TEST BEFORE
COMITTING...  Here are some of the issues:

1)  Scan period is 250 ms.  This means it should work with
typical 300 ms TXDs of other TNC's but will miss packets
the shorter it gets.

2) If 39 is busy with a packet, then the scan will pause
there, and you wont hear anything on 144.99 unti 39
clears.  But at least once your pocket tracker does
BEGIN a packet on 99, it wont be clobbered in the
middle by another packet on 39.

3) I tested it with a D7 instead of a pocket tracker
just to see if the packet could get through the 
scanning and it did.  But I did not have time to
measure statiscs of success...

But One thing for sure, I may put 146.52 in my CALL
channel and let it scan between 144.39 and call channel
when on trips listening for voice alert stations *and* 52
*and* Band-B which will be on the last-heard voice
repeater...  Sort of 3 way listening?

Anyway, just something to think about.

de Wb4APR...

>>> mckeehan at mckeehan.homeip.net 09/22/05 4:32 PM >>>
Does anyone know of any groups that have built several trackers for the group
to use during events? Not the property of any one individual, but the property
of the group?

OR any individual that has built several trackers for deployment during an event?

I'm looking for recommendations on 1) configurations used; 2) bulk discounts
available and 3) any tips on such an effort.

-- 
William McKeehan
KI4HDU
Internet: mckeehan at mckeehan.homeip.net 
http://mckeehan.homeip.net 

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