ISS Repeater

Most satellite trackers tell you when the ISS passes over you. This app tells you when you and a second station are within radio range for communicating. The ISS carries a cross-band FM repeater. To make a contact through it, the station has to be above your horizon and above the other operator's at the same moment. ISS Repeater finds those windows for any two stations, up to seven days ahead. TWO STATIONS, OR ONE In DUAL mode, enter both stations and get back only the windows you can actually share. In SINGLE mode it works as a straightforward pass planner for listening to the repeater yourself. Coordinates go in three ways: typed, dropped as a pin on a map, or taken from your phone's own GPS fix. A DOPPLER SCHEDULE, NOT JUST A PASS TIME The downlink drifts about 20 kHz from one end of a pass to the other. Each result card lays out five receive channels across 437.790-437.810 MHz and tells you when to move to each one and when to leave it - separately for each station, so both operators can work from the same plan. FIND IT IN THE SKY Tap LIVE VIEW and hold the phone up. The camera shows the horizon, the compass points, the whole arc of that pass, and a marker on where the ISS is right now. When it is out of frame, an arrow points the way to turn. Azimuth, elevation and range are read out along the bottom. Bearings are TRUE, not magnetic. The app carries the World Magnetic Model and corrects for declination at your own coordinates, so what you see lines up with a rotator readout or a map. SAVE A PASS, GET A REMINDER Tap SAVE on any window to keep it. Saved passes keep their numbers current against freshly fetched orbital elements, and an optional notification arrives ten minutes before each one opens. NIGHT MODE Black background, red text, for use at the radio without wrecking your dark adaptation. PRACTICAL NOTES - Orbital elements come from CelesTrak, with AMSAT as a fallback, and are cached on the phone. Once they are there, searching, Doppler planning and the sky finder all work with no connection at all. You can paste your own element set instead if you prefer. - The app predicts geometry, not equipment. The repeater is powered down for some crew operations, EVAs and school contacts. A window means the station is mutually visible, not that it is transmitting. - Uplink and operating practice are yours to get right, according to your licence class and national regulations. PRIVACY No accounts, no analytics, no advertising, and nothing about you is collected or transmitted anywhere. The only requests the app makes are for orbital elements, and for Apple's map tiles if you use the map picker.