Today’s goal - help Jim Reed (N4BFR) @N4BFRVision make his first International Space Station (ISS) FM repeater contact. Jim is a long-time friend of mine, who’s very active in the amateur radio community nationally and locally. The ISS pass for today was directly overhead Atlanta, making it an ideal pass. The ISS approached from the southwest so we heard stations from Mexico and the southwest US first, finishing up with stations in the northeast.
The gear I used included: Kenwood TH-D74 radio for transmit, Icom ID-52 radio for receive, Arrow dual-band Yagi antenna for VHF & UHF, and a handy Bulbag USA pouch for my radios. I used the GoSatWatch app on my iPhone to track the ISS as it passed overhead.
The ISS FM repeater frequencies are: Uplink - 145.990 MHz, 67 Hz PL tone and Downlink - 437.800 MHz +/- 10 KHz for Doppler shift. Because the ISS is traveling over 17,000 MPH, the UHF downlink frequency has to be adjusted for the Doppler shift. Practically speaking, that means that I start by adding 10 KHz to the frequency (437.810 MHz) and slowly decrease the frequency as it passes overhead. By the time the pass is almost finished, my radio will be 10 KHz less than the target frequency (437.790 MHz).
So, was I successful in helping Jim make his first ISS contact? Can two handheld radios be used to make contacts using the ISS? Watch this short video and find out!
73,
Joe KI4ASK
PS - I am not a professional YouTuber, nor do I make money from these videos. I do, however, enjoy sharing our love of the outdoors and ham radio with others. The video was shot on an iPhone and put together using iMovie on an iPad. In order for you to enjoy a realistic experience, I do minimal editing.
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