[amsat-bb] Falconsat-3 and APRS HT's?

Greg D ko6th.greg at gmail.com
Mon Oct 2 23:14:57 UTC 2017

Ok, so I must be doing something wrong.  I have an RTL-SDR dongle hooked
to a deep-fringe TV antenna in the attic which is my all-purpose scanner
setup.  I can barely make out the 9600 baud downlink from FalconSat-3 in
the GQRX Waterfall, seeing a good bit of fading during the pass.  At
best it's a faint bar; mostly not there at all.  My D74 hand-held, with
a Diamond RH-77B whip antenna decodes nothing, assuming there was
something to decode.  Tried this on 3 passes this afternoon.  Nada. 
APRS traffic on 145.39, by comparison, shows up really well.

I thought I read that the satellite had a nice strong downlink. 
435.103, plus or minus.  I've not done much of anything with 9600 baud
packet, so don't have much experience to draw from.  What's wrong? 
Equipment, operating, or expectations?

Greg  KO6TH

Patrick STODDARD (WD9EWK/VA7EWK) wrote:
> Hi Bob!
> There are more than a few of us who have tried FalconSat-3 with
> the HTs capable of 9600bps APRS. The TH-D7 and TH-D72 are probably
> the best HTs for this, as they are capable of full-duplex operation.
> I have used my TH-D72 to make a few QSOs last weekend, and I have
> also used other combinations of radios to get on these passes...
> 1. TX: TH-D74, RX: another TH-D74
> 2. TX: TH-D74, RX: TH-D74 and SDRplay with HDSDR & UZ7HO's
>    HS-SoundModem
> 3. TX: TH-D74, RX: SDRplay with HDSDR & HS-SoundModem
> 4. TX: TH-D74, RX: SDRplay w/HDSDR, HS-SoundModem, UISS
> With all of these radios and combinations of radios, I have been
> using my Elk Antennas handheld 2m/70cm log periodic, going through
> a 2m/70cm diplexer whenever I'm using more than just the TH-D72.
> For a few of these passes where I used the SDR receive setup, I
> have made RF recordings. Using the UZ7HO or UISS programs, I am
> also making logs from each program. For just the HT, pictures of
> the HT's screen showing the messages exchanged with other stations
> and other information like position packets. I have posted files
> in my Dropbox space at http://dropbox.wd9ewk.net/ (look for folders
> with "FalconSat3" in the folder names).
> I just tried the 4th setup listed above for the first time on the
> 1756 UTC pass this morning. As I've seen before, I am receiving
> more data with the SDR setup than with the HTs. I saw my own packets
> passing through the digipeater - my position/comment packet, as well
> as a couple of messages sent to ALL. I haven't tried using the
> software directly to a radio, but I have a SignaLink USB here, and
> may work on that. The SDRplay, along with HDSDR's AFC function,
> works very well on the downlink. I normally don't have to make any
> adjustments to the downlink frequency during passes, as long as I
> am reasonably accurate in pointing my antenna skyward. UISS makes it
> easier to keep track of call signs, rather than just looking at the
> HS-SoundModem window - especially when a burst of packets show up on
> the screen, and I might miss something as it scrolls off the window.
> I have two more really nice passes this afternoon - 1935 and 2115
> UTC. I am going to use the same setup on those two passes, and hope
> to see other stations using the digipeater like me. Maybe I will add
> to my short list of FalconSat-3 QSOs (currently at 3)...
> 73!
> Patrick WD9EWK/VA7EWK
> http://www.wd9ewk.net/
> Twitter: @WD9EWK or http://twitter.com/WD9EWK
> On Sun, Oct 1, 2017 at 3:20 PM, Robert Bruninga <bruninga at usna.edu> wrote:
>> I was confused.  I thought FALCONSAT-3 was a PACSAT protocol store and
>> forward system because I thought I saw people trying to get the old PB and
>> BG code,  But the AMSAT web page says it is 9600 baud GMSK up and down.
>> https://www.amsat.org/falconsat-3/
>> 435.103 MHz down and 145.840 up DIGI call of PFS3-1.  While of course
>> setting 5 memores to chase the Doppler the full 20 KHz during the pass.
>> So I am surrprised that I havent heard of anyone making contacts with any
>> ole' APRS HT or Mobile...  All of these radios can do 9600 baud and APRS
>> natively..
>> Im under Kitchen arrest until 1st grandkid arrives soon and cannot play.
>> If I missed something, ignore me.  Ill go back under my domestic rock...
>> Bob, WB4APR
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