In commemoration of the 20th anniversary of the International Space Station (ISS), amateur radio operators aboard the ISS have been transmitting images via Slow Scan TV (SSTV).

More information about SSTV on ISS can be found: Here.

Details about the intracacies of going about receiving SSTV from the ISS can be found: Here.

Below, Logan (KJ6RIF), aims a yagi antenna in the direction of the ISS in order to receive the SSTV image along with Sheri (KJ6BER) who was working the radio and SSTV application.

This is the image that was captured between 2024 PDT and 2034 PDT on 23 July 2017. You will note the more severe static 1/3 of the way down the picture- where the ISS flew behind a palm tree in my front yard and lost Line of Site (LOS) with the antenna. The static near the bottom was when the ISS was leaving the LOS behind the horizon.

Sheri (KJ6BER) captured this image using a hand-held VHF radio with a directional yagi antenna that was pointed at the ISS. Clear skys permitted visual contact with the ISS making antenna aiming easier. There was a noticable difference in sound quality between vertical and horizontal polarization of the antenna (Horizontally polarized was noticibly higher audio quality). This image was captured 8 hours later than the previous image on a different pass of the ISS. This pass occured between 0431 PDT and 0441 PDT on 24 July 2017.

There was another pass of the ISS a few hours later. This particular pass had a much higher arc and passed nearly overhead of my location. (88 out of 90 degrees in elevation overhead of my location.) This provide much clearer audio and resulted in a more high quality image such as the image above.

Simultaniously during this second pass, I was also playing with doppler shift on a Yaesu FT-991 with a roof mounted vertical antenna. The vertically poloraized antenna did not lend itself well to the receipt of this image. There was one shift in frequency to account for doppler effect. When the transmission began, the radio was tuned to 145.800 while the ISS was directly overhead, then 1/2 way through the transmission of the photo, the frequency was shifted to 145.7975 to account for doppler effect while the ISS was traveling away at more than 28,000 kph. Notice how the quality of the image was becoming highly distored prior to the shift in frequency. Had the doppler shift been used with a directional antenna, there is no doubt this would have resulted in the highest quality of each of these three images.

Special thanks to MARC President: Rob WO4ROB, for making the announcement about this particular event. Fun was had by all who were on the repeater (and those where were listening as well).

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