SENDING EMAIL via the APRS Capable Satellites de WB4APR --------------------------------------------- --------- Any of the APRS capable Amateur Satellites are capable of forwarding EMAIL messages from mobiles or remote traverlers. While such service is not guaranteed, it does work some of the time. It could work well all of the time if we had more people listening to the satellites! The format is simply sending an APRS formatted Message to the call- sign of EMAIL. Then make the first word of the message be the e-mail address of the recepient. That is all there is to it. Of course, and APRS message is only one line long, but a few words can mean a lot. The PATH Taken: --------------- If the message is succcessfully digipeated by the satellite, you will probably see (or hear) the digipeated copy and know that your uplink was successful. If it was, then there is also a good chance that one of the many APRS Satellite ground stations saw it and forwarded it into the worldwide APRS internet linked APRS distribution system. Monitoring that system (and every APRS packet in the world) is WU2Z's e-mail engine at Rutgers University looking for any APRS messages to EMAIL. If it sees such a message, it takes it and puts a standard Email header on it and then injects it into the normal Internet. His engine also sends back an ACK to let you know that it was processed. Sometimes, especially via the satellite path, this ack may not make it all the way back to the sender... but the Email will be delivered anyway. What Can Go Wrong? ------------------ The WU2Z Email engine may go down, but over the years, it is normally quite reliable. The biggest unknown is whether there was a satellite I-Gate monitoring the satellite downlink to hear your packet. These signals are weak and any one ground station does not hear all of them. But the design of the APRS internet linked ground station system assumed that there would be lots of such ground stations (simply an OMNI antenna, a 2m Radio and a PC is all that is needed). In my opinion, we need about a half dozen more stations in the USA. Europe does quite well with at least 4 permenant stations on line always. ANYONE can be an APRS Satellite ground station simply by using APRS or other softare to listen on the downlinks and feed all packets heard into the worldwide APRS internet linked system. YOU CAN HELP. SATELLITES: ----------- The following satellites can digipeat any standard AX.25 packet and thus can be used for APRS or Email. The critical difference between them is how many ground stations are monitoring. PCSAT-A: Easy uplink and downlink. Excellent chance. Lots of stations monitoring the 145.825 downlink worldwide. PCSAT-B: The dual redundant system on PCsat. It downlinks on 144.39 and the downlink will always be heard somewhere. The uplink is unpublished so that we can provide "good" service to special stations on special travels (apply in advance). ISS: Easy uplink and downlink. Good chance. But ISS is often not working, there may be fewer ground stations, and there is lots of competition on the uplink. UO-22: Easy uplink, but downlink requires tracking gain antennnas. Probably no one is listening (bummer, because it is so good!) Sapphire: Easy uplink, but downlink requires tracking gain antennas and no one is listening. OPAL: Difficult uplink and downlink and no one is listening... SENGDING WITH NON APRS PACKET STATIONS: --------------------------------------- If you are not running one of the APRS Mobiles or HT's from Kenwood or a copy of APRS software but still want to send an Email via any of the satellites with just a dumb-terminal mode and a TNC, then you need to do the following: cmd: UNPROTO APRS VIA DIGI <== where digi is the call of the satellite cmd: CONV <== go to converse mode :EMAIL :abcdefg@higjlmn.net Text begins here for one full line only. And that is all there is to it. It all has to fit on one line. Enjoy the system and think about putting one of your spare packet systems to work monitoring any of the above satellties to help out your fellow travelers. de WB4APR, Bob