FIELDday.txt      APRS At Field Day
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Document version: K30
Document dated:   13 June 2002.  Previous version was 14 Sep 2001
Author(s):        Bob Bruninga, WB4APR <bruninga@nadn.navy.mil>
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There is a very definate way to save bandwidth at FieldDay or another
on-air event where you want to QSL the maximum number of 2-way comms.
Normally, if 16 stations want to all QSL each other for 2-ways, it would
take 256  individual messages (Impossible!).  The technique used by
APRSdos (and built into APRStk) will reduce this to only 16 messages.

ANY APRS program can use this technique, although some are easier than
others.  In APRSdos it is easy, and I even made it an AUTOMATIC mode
in my satellite tracking version of APRS called APRStk.  This program
is handy at FIeld Day, because not only can you use it for all normal
FD ops on 144.39, but it always shows you when satellites are in view
as well, so you wont miss any satellites too...

APRStk has a FIeld Day AUTO-QSL mode built in to automate, simplify and 
streamline QSO's for APRS at Field Day.   If you are new to that program
be sure to read APRStk.TXT.   APRStk is a copy of APRSdos 
with additional features for casually monitoring the amateur satellites.

FIELD DAY requires an exchange of STATION TYPE and ARRL SECTION between
stations.  If there are 20 APRS stations, this could add up to 400 to 
2000 packets depending on the number of retries (5), since every station
must send a QSL message to every other station for a valid QSO.  This 
is clearly an equation for total QRM failure.  


MAUNAL QSL PROCESS:
-------------------

APRS solves this problem by bundling up multiple QSL's into single one-
line bulletins.  THus, one single packet can be QSL'ing as many as 8 
other stations as follows:

   BLN1CQFD:QSL 3A MDC,wb4apr,n8deu,kb2wqm,aa3jy,wa4hfs,wb4gcs,ka4pfn
   BLN2CQFD:QSL 3A MDC,wa4tfz,k5znl,k0cy,n0clu,ka3ati,k3for

As each new station is heard, you simply COPY the previous BLN# and then
type in the new call on the end.  This is easy to do in any version of
APRSdos with the following Key strokes.

S BLN1CQFD (ENTER)      <- re-enters the same BLN# as before
#  (ENTER)              <- COPIES the previous line (#)
XXXXXX (ENTER)          <- Adds the new call on the end
E # (ENTER)             <- Then ERASE the old copy


AUTO-QSL MODE:  
--------------

You can do this with ANY version of APRSdos.  But in APRStk, these 
Bulletin QSL's can be done automatically with the alt-S-MODES-QSL-AUTO 
mode.  Here is what it does while in AUTO mode:

  1) Set alt-S-MODES-QSL-AUTO mode to on

  2) Displays QSL-AUTO mode in the upper right corner
  
  3) When the pass (or FD) begins, enter a BULLETIN message:
     TO :BLN1QSL  :QSL 1A-MDC
     Where in my case 1A-MDC is my station and ARRL section.  
     The key word is that it must begin with "QSL".

  4) APRStk will now watch the POSITION-LIST for any NEW call from any 
     station that is NOT one of the following:    
                              !DIGI and !!WX
                              $NMEA and $ULTW
                              /Fixed stations
                              * and # WX stations
     And then automaticlly ADDS this call to the existing BLN# message
     under the following conditions:

  5) The LAST SEND line must begin with "BLN" and the FIRST 3 characters
     of the message MUST be "QSL".

  6) ONCE the P-LIST fills and begins bumping old stations off the list,
     then this automatic process will cease.

As you can see it is fully automatic.   This works great on the satelites 
where every new call is one that you want to QSL.  It could be a mess at
Field Day.  So I might use APRSmax and do it manually as shown above
so that a Hmuan is in the loop, and I am only QSLing active other FD
statoins and not the other hundreds of stations on the air.

When AUTO-QSL hears ANY new station, it will
add that station to the QSL Bulletin., reset the timers and resend the
bulletin.  THus you never have but one BULLETIN on the air, yet you are
providing multiple redundant QSL's as the bulletin grows.  Once it fills
up one line, then it automatically begins the next one BLN2QSL  :1A-MDC
so that it will continue building this new Bulletin.  

The first one then begins to decay, since it is now old, and the new one
is updated on each new station..

You may count as a valid 2-way exchange every station that YOU both 
1) SAW, and that  2) YOU saw HIM QSL you.

NOTE:  Since AUTO-QSL mode will QSL any station that is "new".  It only 
konws this by the stations in the P-LIST.  So begin your event with an
empty P-LIST if you want EVERY station to get a QSL.  Once the list fills
up, then it will cancel AUTO-QSL mode.

Enjoy,
de WB4APR

