Patrick, I haven't worked ISS Packet lately but will give it a try. As I recall and confirmed by the following link, packet is downlinked on the 145.800 MHz voice frequency when they are not doing voice. That is the ISS crew turns the radio to packet digipeater mode when they are not on voice. The packet uplink frequency is 145.990 MHz. The following link gives more info: http://www.amsatnet.com/iss.html. Steve