[aprssig] Falconsat-3 - The APRS satellite for Mobiles

[Robert Bruninga]

Work a satellite from your APRS mobile, 5 times a day:



For APRS folks just sittin in their mobile with nothing to do, you can work
FALCONSAT from any APRS Mobile…  Just confirm passes using Heavens-above.com
(be sure to enter your location).  Though passes now are from about
midnight to 6 AM, that pattern moves earlier about 36 minutes a day so it
will be in the evenings in a few days.



The Falconsat digipeater operates APRS at 9600 baud and works fine from a
50W APRS mobile with mobile antenna.  Just turn on your rig, set the
internal TNC to 9600 baud and monitor the downlink.  You should see packets
from PFS3-1 and or other stations.



Tune 435.110 MHz at start of pass, then clicking down steps of 5 Khz
towards the middle of the pass and then ending at 435.095 by the end ten
minutes later.  If you are just going to monitor overnight, set to 435.105
for the early middle of the pass and check your LIST in the morning.



Uplink takes a bit more settings.  Set your PATH to go via PFS3-1 and set
TNC to TX A and  RX B and set uplink on band A to 145.84 (no need to step
doppler).  Set beacon to once a minute (and turn off decay and
Proportioinal pathing).  You will NOT see your own digipeats.  Although the
satellite and D710 are operating full duplex, the D710 TNC is not.  By the
time the TNC TX/RX turns around, you will already have missed it.  So don’t
just keep TXing until success,  You WONT see it.  But when you DO see
someone else doing APRS, then by all means send them a message.  If he
ACKS, then success!



I just did the math.  You don’t even need no stinkin computer.  Once  you
hear a pass, then just remember that passes are 36 minutes earlier each day
and the next pass on any given day is 98 minutes later (unless that was the
last pass of the day).  During a western trip, just jotting down the time
of a pass heard, then I could predict pass times therest of the day and
every day for weeks.  Always just adding 98 minuets to the next pass and
listening 36 minutes earlier each day.  See this manual technique:
http://aprs.org/MobileLEOtracking.html



Here is how WD9EWK describes working FALCONSAT:

https://www.amsat.org/wordpress/wp-content/uploads/2018/03/FalconSAT-Stoddard-pdf.pdf



Anyway, it’s a great satellite while mobile that needs no special
antennas.  Just keep up with when it is generally coming over and have the
frequencies already programmed into a channel in your radio.  Actually,
program four frequencies to make it easy to shift for doppler.



We will try to remind everyone when passes enter more favorable evening or
morning commute hours…



And here is a note I got form himpatrick at wd9ewk.net today:

Bob, WB4APR



*From:* Patrick STODDARD wd9ewk
*Subject:* Re: [amsat-bb] D72 to Falconsat-3 APRS



FalconSAT-3 uplink sensitivity is good. I regularly work it

with 5W from my TH-D72 with a handheld beam… I have used a TM-D710G at its
various power levels, and 5W from the mobile radio works fine.



Downlink power... it is strong. I can hear it a few degrees

above the horizon.



I have used a TH-D72, TM-D710G, a pair of TH-D74s (The TH-D74 cannot
operate APRS crossband)



I wrote about using these different radios, and combinations

of radios, for the AMSAT Journal in late 2017:



https://www.amsat.org/wordpress/wp-content/uploads/2018/03/FalconSAT-Stoddard-pdf.pdf



73!

Patrick
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