[aprssig] APRS HT Event

Bob Bruninga bruninga at usna.edu
Sun Jan 16 13:02:26 EST 2011

Just completed our annual Klondike Derby with APRS HT messaging support.
Every hour, 20 stations reported scores from 20 scout outposts for up to 5
troops at a time.  We used APRS HT's for messaging the data to HQ, and a
D700 mobile display head on a clip-board at Headquarters for accumulating
the scores that  were then passed on to the computer data base operator.


Lessons learned:


1) Over the many years, we have gone from 20 ops and 3 APRS Ht's to 5 HT's
to 8 Ht's and this time to 100% APRS Hts for all stations.  The problem is
we no longer can find 20 hams.  As APRS has increased, the number of
volunteers has dwindled to having only about 10 hams.  Had to use MURS
license free voice radios at the other stations. (We had enough spare APRS
HT's, but what's the use training a one-time operator?)  Each APRS operator
walked back and forth and reported on at least 2 stations each to cover most


2) Net control needs a voice radio independent of the APRS radio so that he
can use voice without having to abandon the APRS message window if he needs
to make a quick transmission. Wastes the dual-band of the D700, but is
essential so that operator can read messages independently of radio voice


3) On a lightly used net frequency, the Net control operator could alert
those in the field when he is idle and can take trivial or routine queries
from the field.  In the field, we cannot tell when he is up to his eyeballs
in headquarters issues and hate to interrupt with a trivial question.
Therefore we suggest:


ON a voice net, when the voice channel is idle AND net-control operator is
"idle" and between tasks, he could simply make a voice transmission "This is
net, standing by".  This alerts all of the rest of us out in the field, that
NOW he is happy to handle any low-priority traffic.  Thus preventing us from
interrupting him when he -IS- busy.


4) With the new D72 and VX8G HT's with built-in GPS it was trivial to track
the Scout's VIP golf cart.  I just flagged him down, and took 1 minute
duck-taping my GPS-HT to one of this window posts, and we were able to track
him all day.


5) My D72 battery lasted all day.  7:30 AM to 3:30 PM running the dual band,
and TNC and internal GPS!  All operations were done on low power (not EL
power).  I was amazed.


6) We used 445 MHz for APRS so that APRS worked full duplex with voice at
all stations including net control.  It was cute to hear our "incoming
message" on his D700 in the background when he was talking (on 146 MHz).


For more background on this annual event see www.aprs.org/aprsevent.html

Bob, Wb4aPR

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