[aprssig] SET 2009 APRS report

Robert Bruninga bruninga at usna.edu
Sun Oct 4 10:29:15 EDT 2009

Did you use APRS for your County SET this year?

Here is my APRS report for our SET in Maryland:

During the SET, an APRS client was run on a portable laptop/HT
connected to the VHF(air) antenna at the AA County EOC.  Other
PC's at the EOC or throughout the county could see the APRS
virtual map and all stations, mobiles and objects on the APRS.FI
web page.

APRS was active from 9AM to about 11AM.  During that time, in AA
County, we observed 8 fixed stations, 7 mobiles, 3 boats and 4
objects.  In addition, the APRS.FI site map overlayed the
positions of several dozen Marine Mobile ships, boats and craft
with VMS transponders giving an excellent virtual display of the
tactical situation in the area.
Within the first hour, the number of APRS stations, and mobiles
on APRS RF within the greater Maryland and metro areas exceeded
200 active stations.

Three of the APRS mobiles were innvolved in the SET, N3HU-9,
N3WOF-9 and WB4APR-9.  Using APRS we were able to establish
comms with one additional mobile N3SNU-1, and shared messages
with the New Jersey Emergency Management station NJ2EM at the
EOC in Trenton.

APRS bulletins, and messages were exchanged with the AACO
mobiles above, located in the Park-N-Ride staging area in
Millersville.  APRS Voice coordination was setup on 446.15 MHz.
The APRS console at the EOC was used mainly for message and
object entry.  Any 'thing' of significance to the SET was placed
on the virtual map so that everyone in the EOC, mobiles, or
anywhere with internet or APRS access could see the tactical

In addition, the Universal Messaging between APRS and Winlink
was exercised by sending one-line APRS messages to Winlink
accounts.  The reverse direction was also tested, that is,
receiving Winlink message alerts on the APRS radio each time new
Winlink traffic was received in the Winlink account.  But the
exercise was completed before this capability was verified.

CONCLUSION:  APRS should not be considered as only a vehicle
tracking system.  Using objects and messages, it becomes a
virtual display and all-call message space for sharing all
information pertaining to the situation.  Anyone with APRS
laptops and radios, or with internet access can make immediate
use of this information.  There is no prior-knowledge required
for communication other than RF users and mobiles bringing up
APRS on the national 144.39 channel, and internet users
accessing APRS.FI, or OPENAPRS.NET or FINDU.COM.  Even with all
voice channels busy, we could send coordination messages and
notes to the mobile APRS operators without interrupting voice

LESSONS LEARNED:  I am reluctant to make the above suggestion of
using APRS on the internet because it violates all principles of
amateur radio emergency preparedness and undermines the effort
to get volunteer members to setup their own APRS laptop RF
portable capability.  But after nearly 16 years of APRS, it
seems to be the only way to get people to become familiar with
APRS.  But, I grant that familiarity must come first.  Second,
cell phones were reluctantly used during the exercise to
establish amateur radio contact.  Though this show initiative on
the part of operators, this capability probably would not exist
in a large local disruption.

Pre-testing of all cables and connectors is a must.  A BNC
barrel and PL250/BNC adapter somehow had 40 dB of attenuation
though the pair looked perfect to the eye.  This led to 30
minutes of lost time during initial setup.  My briefcase APRS GO
kit should contain an AC power 1-to-3 adapter so I can plug into
already full outlets.

Operators in the EOC were energetic and resourceful, but we did
not have passwords for any of the installed PC's at the radio
operator positions (other than the few dedicated ham radio PC's
(Winlink, etc)). 

APRS display of Marine Traffic in the Chesapeak Bay and
surrounding waters was a bonus that  should be part of the
Marine Band operating position.


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