So far, the ARISS SSTV event that started on Friday (8 February) has been disappointing. The pictures are being sent down as scheduled, but signals from the ISS on 145.800 MHz aren't as strong as they usually are for other SSTV events. I usually can start a clean decode of an ISS SSTV transmission when the station is only a few degrees above the horizon, but not today. The best picture I could get so far was on a pass in the past hour, as the ISS approached the midpoint of the pass:
If you want to test your SSTV setup, I have a bunch of WAV files that can be played into SSTV software. Visit my Dropbox space http://dropbox.wd9ewk.net/ and look in one of the following folders:
Today's transmissions and WAV files are in the "201902-ISS_SSTV" folder. Many of the recordings in the other folders will yield better pictures than the recordings I've captured today. I ran the WAV file for the picture above through a Windows SSTV program, RX-SSTV.
During the night, an ISS crewmember fixed whatever was the problem with the SSTV transmissions on Friday. As of a pass I just monitored in the past hour, the signals are back to where they normally are for an SSTV event - loud, even when the ISS is near the horizon.
I just had a pass starting at 1710 UTC, where the ISS only went up about 9.5 degrees above the horizon. I started hearing the SSTV downlink within seconds of the ISS popping up from the horizon, and received a partial picture:
A couple of minute later, the next transmission yielded a clean and complete picture:
I used the same setup today as I did yesterday, and for other recent SSTV events: record the transmissions with a Kenwood TH-D74 and Elk Antennas handheld log periodic antenna, and then decode the recordings using RX-SSTV on a Windows 7 laptop.
There are still more opportunities to receive these transmissions, and now it should be a lot easier than yesterday. If you receive any of these transmissions, ARISS would appreciate receiving a copy of the pictures. Pictures can be uploaded to the AMSAT SSTV gallery.
I was at the Yuma Hamfest in Arizona for the past couple of days, and had a chance to copy one ISS pass this morning around 1600 UTC. I used my TH-D74 & Elk log periodic antenna to receive the transmissions. Not only did I record them with the TH-D74, I also had the Robot36 Android app on my phone to decode the signals in real time. I downloaded the app about 20 minutes before the pass, but didn't do much other than find where I could specify the SSTV mode as PD120. The first picture was chopped a bit by the app, but the second picture was decoded perfectly.
This is how the Robot36 app looked, after the complete picture was received:
The picture by itself, from the Robot36 app:
After the pass, I took the WAV file from the TH-D74, converted it from a 256kbps WAV file to a 48kbps WAV file, and then ran the 48kbps WAV file through QSSTV on my Linux laptop. The recording had both pictures. The first picture:
Then the second picture, the one I received using the Robot36 app, decoded by QSSTV:
Looks like QSSTV was able to straighten out the text below the picture of the Columbia launch, where the picture from Robot36 shows some slanting in that text - a visual indication of the Doppler effect on the signals from the ISS.