Monday, July 24, 2017

ISS SSTV Event Results (July 2017)

To celebrate the 20th anniversary of amateur radio aboard the International Space Station, the ISS transmitted SSTV images all weekend long. I tried a couple methods to capture these images with varying results.

Out of all the satellites buzzing around in the sky, the most interesting one in my opinion is the International Space Station. Equipped with amateur radio equipment on board it brings a new aspect to the hobby. Not only do they use the equipment to make voice contacts on the ground, you can also utilize the ISS as a digipeater for APRS traffic, and on special occasions you can even receive pictures from them.

For the ARISS 20th anniversary, the ISS was transmitting SSTV images all weekend, using 25 watts, and pausing for about 3 minutes between images. I've played around with receiving these images before so I had a good idea of what I was doing, but I decided to experiment with a couple different ways.

FYI: You don't have to be a ham radio operator to participate in this activity. You can easily grab an old scanner tuned to 145.800, install the Robot36 app on your phone and hold it close to the speaker. It's really that simple.

The first method I used was with the new Baofeng Tech APRS-K2 cable. I connected my UV-5re HT and a NA-771 whip antenna to my Galaxy S7. I used the Robot36 android app to decode the images as they came in.
ARISS SSTV Image Captured with HT and Cellphone

ARISS SSTV Image Captured with HT and Cellphone

ARISS SSTV Image Captured with HT and Cellphone
As you can see, the results were just okay. I think the three times I tried with the handheld, the ISS went too far over the horizon and I got nothing but static toward the end. This happened because of bad luck really. I had a good pass each time, but the 3 minute delay between transmissions meant that by the time my phone got the signal to start receiving the image, the pass was already halfway gone. But, it's still exciting to watch images coming from space through my phone and a basic handheld radio.

The other method I tried was simply using my home station. I have a Kenwood TM-281 connected to a 2 meter j-pole antenna on a 30 foot mast. I've got the radio connected to a desktop computer with a sound card and ran the MMSSTV program

This method was a lot more successful. Mainly because it was setup to continually listen all weekend long. I had more images than what is shown above, but they were not very good copies. 

The j-pole at 30 feet did a great job at my home station. Since it's elevated above a lot of the surrounding trees and terrain, I could start receiving an image when the ISS was just a couple of degrees in elevation. It also helped that the ISS was using 25 watts of power. 

One thing I did notice was, the best results were when the ISS was passing between about 5 and 45 degrees in elevation. This is because the j-pole directs it's gain closer towards the horizon and not straight up. So even though you might think a high pass directly overhead would be best, it really isn't.

In conclusion, this was a fun weekend project. I liked using my phone and a handheld radio to receive the images even if the quality wasn't perfect. It was also great to be able to leave my station at home listening 24 hours a day to catch every single pass too. I could walk over to the computer and browse through all the new images it was able to pickup. I greatly suggest giving this a try next time they have an SSTV event!

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