(an archived page, this may contain outdated or
tactical communications solution ...
speaker . . .
Tim Cunningham - N8DEU .
is considered by many as the local 'Packet Guru'.
is also known as an Area Coordinator for AMSAT Field Operations.
presentation of APRS as a tactical EmComm solution,
an article submitted to the Huntsville Amateur Radio Club, by N8DEU.
originally in the HARC-VOX
newsletter for July 2008 pages 5,6 &7)
this article was prompted by Doug's ARES
District 6 article
in the HARC-VOX
newsletter for April 2008.
-Doug Hilton <
WD0UG > was discussing the value of effective NCS protocols.
Tim has graciously allowed SomeNet to re-publish this article.
is part < 1
> of a special series)
|I read Doug Hilton’s
comments from the “ARES
District 6” article in the VOX from April with
great interest. It was clear to me that the APRS
Tactical Communication system can easily fix just about all the
problems on the Emergency Net. Having to repeat callsigns 5 or 6 times
to check into any net is unacceptable. Not being able to get HAM’s to
use the proper international phonetics is just another confirmation
that we are all human and suggests we need better methods. Have
I failed to communicate effectively over the years that we already have
an effective communication tool in our Amateur Radio tool box?
solve these issues and provide an effective tool that has been
addressing those needs for many years.
Now that I
have cleared my lungs, lets take a look at the ways APRS addresses each
of the points that were made in the ARES District 6
article in April’s VOX:
The APRS tactical
communication system addresses each of these points and many more. How
does it address these points?
- 1. NCS making 5 or 6
attempts to get the correct callsign from check-ins.
- 2. Operators using
- 3. Priority messages
wait for 10 or 20 stations to check-in.
- 4. Taking check-ins
is a time consuming process to get name, location, and callsign correct.
- 5. Delay time between
- 6. Inefficient
transfer of information.
- 1. Getting the
correct callsign is a thing of the past unless the sending operator
mistypes it. The APRS
network will quickly sort out multiple check-ins as the same time. 10
or 20 stations could be logged into the network in a fraction of the
time it takes to do it by voice. The bottom line is there is 10-100
times more bandwidth available for the important information from
multiple stations. Emergency traffic can actually be passed while
stations are checking into the net very easily.
- 2. There is no need
for phonetics in the APRS
world. What you see on the screen is what you get. In addition, there
is no need to write anything on paper at the NCS station when
because it can be logged automatically in a file for archival or sent
to a printer for automatic documenting.
Priority messages suffer due to the way a voice network and human
interaction work. This is the most limiting factor of any voice
network. It is only as good as the operators and the protocol allow it,
but it is a time consuming process. Priority traffic on APRS is built into
the core operation of the system. New traffic takes precedence over
older traffic. Some may argue that APRS
uses an un-connected protocol. This is true and it is the main reason
that it is so efficient. New messages take priority and traffic is
re-transmitted by an decaying rate while new messages are
re-transmitted more often taking priority. Personal messages are
acknowledged by sending a message back to the sender to stop sending
it. Bulletin messages are the beauty of APRS
as they are sent in the same decaying rebroadcast format and everybody
receives it virtually at the same time with the broadcast protocol.
Thus, newer bulletins take priority in any time critical event. These
messages DO NOT wait for check-ins or anybody else. They are
multiplexed in between check-ins in case of a REAL emergency situation.
I can remember on the old connected packet BBS network when weather
bulletins took forever. When the weather was bad the number of
bulletins brought the network to a crawl. It would take all night to
get all the weather traffic using that old protocol. Today, we utilize
that same equipment employing the APRS
unconnected packet protocol and that problem is gone. Weather bulletins
are sent in real time from the NWS
and broadcast to every APRS
packet station for all to receive immediately. With some weather
bulletins you will be informed exactly how far and in what direction
you are from the maximum area of concern. This is immediate information
and it waits for no operator to send the message or announce it over a
voice repeater. How many times have we experienced storms in our area
and the voice net woke up after the threat had passed through the area.
This simply does not happen with APRS
users are informed immediately as those NWS messages are
broadcast. In fact, with all the weather nodes available on APRS
you can set trigger points for wind speed, temperature, and barometric
pressure to sound an alarm on your APRS station remotely.
- 4. With APRS you can reduce
the check-in time to a fraction of what you experience today. If those
10-20 check-in stations used the APRS
network, the check-in time could be less than 2 minutes, nobody would
have to repeat their information (unless they typed it wrong), your
location information would be automatic and your APRS
symbol would be placed on the map. I know I have refrained from
checking into the voice net many times because of the lengthy process.
Any station can send priority traffic at any point, even during the
check-in process. It is easy, effortless, and better utilizes the
bandwidth for increased traffic when needed. Voice nets will never
compete with the speed of traffic passing on the APRS digital network!
- 5. The delay between
check-ins is a waste of bandwidth. There will be dupes on a voice
network and there will be dupes on an APRS network. The
advantage is the APRS
network automatically takes care of those dupes rather quickly by the
design of the protocol and no human intervention is required. Any delay
is wasted bandwidth that can be used more efficiently to transfer
- 6. Inefficient
transfer of information on a voice network can be a thing of the past
with the APRS
network. Information is sent as the sender intended. No repeats are
necessary that the protocol does not already address.
digesting this material, I read Rolf’s article titled “Madison County ARES /
RACES Update” in the April VOX concerning weather spotter
training. Here is another example of where APRS is a practical
tool for the services of the Amateur Radio Community. APRS is already
weather oriented. No other tool in the Amateur Radio Community contains
the weather reporting capabilities of APRS. NWS weather
bulletins are broadcasted in real time on the APRS network. Those
who utilize APRS
maps will see counties highlighted in red or yellow indicating areas
with watches or warnings posted in addition to the bulletin itself. You
always know how far you are located from the maximum area of concern.
All this information is available on the APRS radio network
as well as the Internet APRS
network since they are seamlessly integrated. Weather is unpredictable
at times and the APRS
tactical communication system fits the mold on VHF or UHF to contain
traffic to a specific area or event. The Internet is nice but it is not
required in a tactical communication system where digipeaters can be
easily installed to make any necessary connections with conventional
radio equipment. APRS
where you are located, which takes away any guesswork by simply looking
on a map and physically seeing your location relative to any activity
that may be of concern. In the end, APRS
is really an informational awareness system and it performs its
function very well.
What better tools do we have for
a tactical communication system? The APRS
infrastructure has grown and continues to grow in popularity with new
digipeaters being added to this tactical communication system. We have
solutions to serve the public interest not just a bunch of toys.
is a pretty cool toy.
picking on the HAM radio population? You bet!
The status quo or old fashion methods may be a little dated for our
nets to run efficiently. Does this make you mad? It should! It should
make you so mad that your blood starts pumping uncontrollably to the
point you get on you feet and think about the problems and the
solutions. If we do not have the solution, then what service will
replace us along with our valuable radio spectrum? How do you spell the
value of Amateur Radio?
Happy APRS Packeting
de Tim - N8DEU
organizations are consolidating some of the overhead associated with
registration and training of the membership. Join us on the 2nd
Thursday evening of each month for a good meeting at the HMC EMA EOC
(and learn more about this).
Remember, the severe weather
season is available year-round.
|Additional discoveries, rants and
and experiments :|
+ Be sure to check www.somenet.net
for interesting articles inbetween updates to this page.
= Narrow Band Emergency Messaging System - check it out (new Yahoo
Propagation Map = using APRS beacons to visualize current
+ APRS.FI = another view of
the APRS-IS database, from Finland.
= My weather instruments are still active and logging.
I'm not yet satisfied with the radiation shield I made for the external
Previous pages from the archives
+ 2008 . . .
+ 2007 . . .
+ 2006 . . .
2005 . . .
organizations, projects and web sites
that I continue to support and
promote : |