[amsat-bb] Successful PSAT SSTV and Waterfall Drawing Experiment

[Brian Wilkins KO4AQF]

For over a month, we have been attempting to TX and RX SSTV via PSAT2. We
discovered on Bob’s APRS page that PSAT2 can support users sending and
receiving SSTV as long as it detects PSK31 in the passband. While we were
unable to get SSTV to work via PSAT2 and experimentations are still on
going, we were able to successfully send SSTV from N8URE in Maryland to
KO4AQF in Florida. This required dozens of cases of trial and error. We
plan to publish the procedure in a future AMSAT journal article.

B/W SSTV:
https://i.imgur.com/nFG6UII.jpg

B/W was easier to decode than color.

In addition to SSTV, we discovered that PSAT will also support waterfall
drawing where the sound will draw the picture directly in the waterfall
display. This provides evidence that when PSK31 is detected that PSAT
transponder may become a bent pipe.

Waterfall picture
https://i.imgur.com/4fdvib6.png

 More experimentations are planned. We attempted to send Olivia however it
was unable to be decoded. This may be due to the manual doppler being
performed and / or fade due to the satellite.

In order to send PSK31 to PSAT, we used upwards of 100-200 watts on the 10m
uplink. Downlink is UHF and must be Doppler corrected. You need a pitcher
and a catcher. In this case, the catcher was manually adjusting for Doppler
on a D72A using an Arrow antenna. Then the catcher used an iPhone Voice
Memo app to record then playback the audio. It can be decoded using fldigi
and SSTV can be decoded with your favorite sstv app.

I’d like to thank everyone who has helped us better understand and
participate along the way. Bob, Brno University, KK4YEL, KI5HHK, and N8URE
who did the heavy lifting of sending the data over the 10m uplink. Brno
University was instrumental in providing the right technical details along
with their github page for us to dial in our transmission.

 More in depth technical details to follow

Signed,

N8URE
KO4AQF
KK4YEL
KI5HHK


-- 
Brian Wilkins
KO4AQF