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Re: The FO birds & FD



On Wed, 8 May 2002, Garie Halstead wrote:

> Would appreciate any feedback as to how much activity you encountered
> on FO-20/FO-29 last year during Field Day.  I'm looking for other
> alternatives other than RS-12/13 (excluding AO-40).

Here are all the FM or packet satellite pass times for Field Day 2002
(Mid Northern Latitudes):

Sats 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 00 01 02 03
---- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
AO27    **********                       **********
UO14      **********                       ***********
SO41        *************            *************
AO16         **********                      **********   <== (not FM)
ISS    *  ******************************
UO22 ******                      ***********
OPAL ***** *                      *** **** *
NO44                             *********** *            ************
NO45                            *************            * ***********

The last 6 are digipeaters and last 5 can all be worked with normal packet
TNC.'s and FM rigs.  The best way to get a valid contact is as follows:

1) Put your exchange in a packet.  Digipeat via the satelilte ONCE.
2) Copy ALL other calls sending their exchange.
3) send a single QSL packet with your exchange and list of all calls
   for which you are QSLing..
4) Watch for their similar QSL packets.

A valid exchange occurs if YOU are in their QSL packet and they are in
your QSL packet.  APRSdos and APRStk can do this all automatically.  Read
SPACE.TXT in the readme files.  A QSL packet looks something like this:

WB4APR>CQFD::BLN1MD-DC:QSL:CALL1,CALL2,CALL3,CALL4,CALL5,CALL6,CALL7,CALL8

The advantage of this technique is that for each 8 people on the bird,
they can make 8 QSO's each for a total of 64 different QSO's with the
total load on the bird of only 16 packets.  Doing it the normal way would
take over 8*8*2 or over 128 packets.... Grossly inefficient (and
impossible).

Of course you never get the ideal due to some dupes, and collsions, but
it sure is better than trying to exchange 4 packets with every single
station!  See the web page:

APRS SATELLITES     http://www.ew.usna.edu/~bruninga/astars.html

de WB4APR, Bob


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