Working your first satellite
The FM satellites such as SO-50 work like a repeater in orbit, and you can use them with a dual-band handheld. A simple handheld Yagi makes a big difference, but on a high pass even the handheld's own antenna can work. Choose a pass with a maximum elevation of 30° or more, find a spot with a clear view of the sky in the direction it rises, and listen on the downlink a minute before it starts. Keep your contacts short, since a pass lasts only around 10 minutes and many people share it. Exchange callsigns and locators, and move on.
Doppler shift
A satellite moving at nearly 7.5 km per second shifts the frequency of its signals. On 70cm the downlink can be up to about 10 kHz high as the satellite approaches and 10 kHz low as it leaves. With FM satellites, start a few kHz above the published downlink and step down during the pass, or put the steps into your radio's memories. Linear satellites such as RS-44 and FO-29 carry SSB and CW, need finer tuning, and are easiest with a radio that can transmit and receive at once.
Where the predictions come from
The page downloads the current orbital elements for amateur satellites from CelesTrak, and works out each pass in your browser with the SGP4 model, the same one used by NORAD and most tracking software. Predictions are accurate to well under a minute for a few days ahead. Elements more than a couple of weeks old drift, so the page shows the date of the data. The ISS boosts its orbit from time to time, so check close to the pass if timing matters.
Reading the results
Maximum elevation is how high the satellite climbs above your horizon, from 0° at the horizon to 90° straight overhead. Higher passes are closer and stronger, and last longer. Direction is where it rises and sets. Azimuth is measured clockwise from true north, like a beam heading. Buildings and trees block low passes, so the 10° minimum is a sensible default.
Questions
When will the ISS pass over me?
Enter your locator above. The ISS passes over most places several times a day, but only some passes are high enough to make contact easily. The table shows each pass's start time and maximum elevation.
Can I talk to satellites with a handheld radio?
Yes. The FM satellites, such as SO-50, can be worked with a dual-band handheld, ideally with a small handheld Yagi. Choose a high pass and keep contacts short.
What is AOS and LOS?
Acquisition of signal and loss of signal: the moments the satellite rises above and sets below your horizon.
Why can't I hear the satellite?
Check you're on the right downlink and allowing for Doppler shift, that the satellite is switched on (check AMSAT's status page), and that the pass is high enough to clear trees and buildings.