by Arte Booten, N2ZRC

     In other articles I've described what The Automatic Position Repor-
ting System is and how to get it set up on your computer and radio.   So
you're now probably telling yourself "OK, great.   I've got all of these
stations appearing on my screen.  Now what do I do?"

     One feature in APRS is the ability to send what we call one-liners;
that is, one-line messages from station to station either direct, or via
digipeaters.  From the main APRS screen press S(end), type the station's
call and .  Then type your message and another .  You'll know if
they got it when you receive an *ACK* which replaces the first five cha-
racters of your message.   These one-liners are the only  situation when
APRS uses anything other than UI packets.

     When you send a message in this manner it will be sent via the same
digipeater path as your position and ID packets.   If the station you're
trying to send to is someplace else, you can STILL send it there (if us-
ing APRSDos or pocketAPRS)  by specifying any of several alternate digi-
peater paths which the program can store for you.   If you press O(pera-
tions) D(igipath) S(ave), you're prompted to enter a two-letter code for
that path via whatever path you choose, such as:

          NJ VIA WB2ZII,N2MH-15,KB2EAR-1,K3ATI-11

to get to Southern New Jersey from Westchester.  To see the paths you've
stored, press O(perations) D(igipath) L(ist).  The MAIN purpose of these
alternate paths is to keep the QRM to a minimum, and to use the most di-
rect and, sometimes, the only feasible path.

     The weather systems  feature of APRS allows you to see weather data
in real-time, transmitted by stations with using several different kinds
of autometed weather stations, including those made by Peet Bro's, Davis
Instruments and Oregon Scientific (which made the Radio Shack unit).

     Depending on which options the weather station owner installed, you
can get different kinds of  information including temperature,  rainfall
amounts (to the 1/100th inch) in the past hour and 24 hour periods, wind
speed, direction and gusts and barometric pressure.   Press W(eather) to
see a list of options to choose from.

     If at any time you wish to cease transmitting without shutting down
the program, simply touch C(ommands) X(mit).   This toggles the TX timer
within APRS.   You will still send out whatever the TNC itself is set to
transmit  at their predetermined periods.   When you want to send a spe-
cific packet  (usually your position),  you can do so by pressing X(mit)
P(osition)  [or S(tatus), M(essage), S(tatus), O(bject) or A(ll), as the
case may be.]

     In order to find a station on the screen, use  O(perations)  F(ind)
(what else!) command.   If you'd like to see something really neat,  try
O(perations) R(eplay) with a mobile station.   You'll see that station's
track being replayed.  To access your TNC you'd use O(perations) C(omms)
T(NC) which leads you to a very basic terminal screen.   To get stations
to appear on your screen faster  (within two or three minutes) you'd use
O(perations) Q(uery), followed by a radius in miles from you.

     Now that you've been QRV with APRS for a few hours,  you don't par-
ticularly want to wait  for all those stations to reappear if,  for some
reason, you have to exit the program.   No problem.   When you shut down
APRS by pressing Q(uit) Q(uit)  ,  it asks if you want to save a
backup (it'll do so by default).   Next time you fire it up, you'd press
F(iles) L(oad), then type BACKUP.BK .  Every time you shut APRS down, it
saves this file, replacing the previous copy.   Be aware,  though,  that
all of those packets are timed,  and any station in this backup that was
heard more than two hours ago will "gray-out" (APRS considers them to be
inactive and makes room for more stations that way.)

     One thing to bear in mind when playing APRS is that the best way to
learn, as with anything else, is by doing.  You can use most of the com-
mands as much as you want.   You're not going to BREAK anything!   About
the worst thing that can happen is a lockup, and this is rare.   Usually
the three-fingered-salute (Ctrl-Alt-Del)  will get you out of it and you
have to start over.  So play with the thing.  I mean, how do you think I
learned all this about APRS stuff, by reading about it?

     Speaking of reading about it,  yes I did.   It's all right there in
the APRS distribution zip file.  You can always read those files by just
pressing F1 F(iles)  and typing in the name of the file you want to see.
One suggestion: if you're a slow reader, press the down-arrow button ev-
ery so often,  as APRS seems to get impatient with you when it just sits
there while you re-read that paragraph for the umpty-umph time and push-
es you back into the program.

     There are dozens of these readme files in the "README" folder.  You
can also see them  (at your leisure and there for the printing) by using
any old text editor.  Many of the answers to your questions can be found
there, sometimes buried deep and not quite as visible as you'd like.

     I hope you've enjoyed this series about APRS and hope to see you on
the map in the near future.   Whenever I see a new station on the screen
I try to send them a one-liner, welcoming them to APRS and offering live
assistance and advice.  Feel free to take advantage of this or ask ques-
questions of any station on the air at that time.  We're all very excit-
ed about this program and think that  "the more, the merrier" is the way
to go.  We've gotten a lot of "converts" in the last few years, and this
situation can only improve so come and join us on 144.390!            73

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|Arte Booten  (n2zrc@arrl.net) AEC for Digital Services, NYC ARES/RACES|
|Riverdale, New York    [FN30bu]    !4052.71N/07354.06WNPHG5370/A=00240|
|PGP Key Fingerprint: D73E B889 C630 6F4A F31F 3083 56BD 0AAD 9996 3B03|
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