When that happens, expect to hear a periodic beacon every 2 minutes. You are also permitted to send unformatted informational (UI) packets to the ISS. In other words, it should be operational for APRS beacons. Please do not use the Packet Mailbox System at this time. The crew will not have the computer hooked up to read your messages at this juncture. I have included some information regarding the packet system below. 1) ISS Packet Callsign: RZ3DZR 2) Frequencies: Uplink: 145.99 Downlink: 145.80 3) Please be courteous and do not transmit on the packet uplink until for have heard the packet beacon. 4) If you copy the packet system, please let us know and save your information for a future QSL card.