ARISSat-1 BPSK Telemetry finally decoded!
Success! After a few failed attempts, I finally was able to decode the BPSK Telemetry. It was the 0832 CDT, 1332 UTC pass over my QTH in Panama City, FL. Max EL was only 15 degrees.
- Rig – Kenwood TR-9000 All mode 2m transceiver
- Antenna – Homebrew 4 element Yagi on a 7 foot PVC Mast
- Dell Mini 9 netbook with a 1/8 Male-Male stereo cable
- Droid X with HamSatDroid for Tracking
I tried a few times to record the file and then play it back through the ARISSATTLM program, but the decoding just didn’t happen. I finally decided to “go live” with the software and just adjust it on the fly. That worked very well for me.
Here are a few hints if you decide to try it: Start by reading the Quick Start Guide, this a super handy thing to review first. You will also need the ARISSATTLM software. Get familiar with the operation of the software and do a test run with some CW audio, that will help you when the moment finally arrives when you hear ARISSat-1 poke it’s head above the horizon. I tested several antennas for this, a 1/4 wave ground plane, Discone, J-Pole and the homemade Yagi. The Yagi was by far the best antenna and it was the closest to the ground at 7 feet, where as the others where between 20 and 45 ft high. I learned that the Yagi in the vertical orientation seemed to work best for my situation but others may have different results. The Yagi was also one of the cheapest, a few pieces of PVC, heavy gauge wire and a SO-239 connector. Try this for a Homebrew Yagi.
As the Quick Start Guide states, start at 145.919 SSB USB and listen for the CW tone. Don’t stay there too long as the CW quickly shifts down the scale. Listen to the audio file below to get an idea what you will be listening for. Be quick and keep the CW “bump” to the right of the yellow line. There are blue and orange lines located at the top of the tuning indicator, it is best to locate the CW somewhere to the right of the yellow but within the blue limit line. If you can hold it there you will be rewarded with successful decoded telemetry as indicated on the bottom of the tuning indicator.
I have included a WAV file to give you an idea what it should sound like. You will hear me manually changing the frequency to keep the CW in tune, or above the yellow line on the tuning indicator. SSB BPSK Audio File: 08.06.2011-08.38.01 – Trimmed – Yagi SSB.
Screenshot of the decoded telemetry:
Here is SSTV from the same pass as well as the FM Audio: 08.06.2011-08.38.01-ARISSat-1
Used to illustrate the ability of the telemetry to still get decoded even in weak signal conditions.