In reply to the 'anon' poster: This mode has not been active for a long while, but the nominal frequencies are: Tx to the ISS repeater on 437.800MHz (FM), and Receive from the ISS repeater on 145.800MHz (FM). If you are a Radio Amateur and you plan to operate on this mode, you must take steps to adjust the above frequencies to allow for doppler shift. On a high elevation pass, you might need to transmit on 437.791MHz and listen on 145.803 MHz. Adjust these to 437.800Tx/145.800Rx as it passes overhead, and shift to 437.809Tx/145.797Rx as the ISS disappears out of range at LOS. Some transceivers do not have small tuning step sizes. You may find you can leave your receiver tuned to 145.800 for the whole of the pass, but you will definitely need to move your Tx to successfully access the repeater at AOS and LOS.