ANDE TELEMETRY/COMMAND/COMMUNICATIONS PROJECT Students: Midn 1/C Patterson Faculty and Staff: Bob Bruninga (WB4APR) MISSION: The Comm payload for ANDE is to provide a flight proven Telemetry and command system for ANDE and if extra power is avaiabole, a secondary mission to augment the constllation of other similar amateur satellites (PCsat, ISS and Sapphire) serving as worldwide position/status reporting and message communications satellites for remote travelers using only Handheld or Mobile radios with Omni-directional whip antennas. It uses the APRS (Automatic Position Reporting System) protocols to permit hundreds of users per pass to access the satellite. This constellation of satellites, will augment the existing worldwide terrestrial Amateur Radio APRS tracking system by providing links from the 90% of the earths surface not covered by the terrestrial network. It will be licensed in the Amateur Satellite Service. BACKGROUND: Today, 95% of the US amateur population is covered by the terrestrial APRS network, BUT only 30% of the surface area of the USA is, or will probably ever be, covered. Similarly in just the last year we have seen explosive growth in the European theater as well. But, distant travelers, boats at sea, and stations in the rest of the world are presently unable to use the APRS system as a travelers safety reporting system when on distant trips. Until the activation of PCsat, the APRS network only covered less than 5% of the world's surface. The APRS payload on these satellites will not only make such reporting possible throughout the world, but by having more than one satellite, will give the program reliability and continuity and connectivity more often than a single satellite can provide. FREQUENCY CONSIDERATIONS: Two meters is the ideal band for this mission due to the requirement for user access using only a handheld radio. Two meters offers a 9 dB link advantage over UHF. To take advantage of this advantage, the HANDHELD uplinks will be on two meters and the downlink will also be on 2 meters. This assures the best reception by mobiles and handhelds both with only omnidirectional antennas. Higher power mobiles who have 10 dB greater uplink power may use UHF but only if there is sufficient power budget on ANDE to support the two receivers. Multiple receivers splits the contention on the uplink channels and doubles overall throughput. DOWNLINK: The downlink is the same as PCsat on 145.825 UPLINKS: The uplink is the same as PCsat on 145.825 for Handhelds and 435.250 for high power 9600 baud mobiles. INTERNET LINKED GROUND STATIONS: APRS is unique in the way it combines all packets heard everywhere in the world into a single common internet feed channel. THus the infrastructure for distributing APRS traffic no matter where its source into all other stations already exists. By adding ANDE on the same frequencies as PCsat, the existing worldwide internet linked groundstations will also link to Starshien with no additional effort. WB4APR, Bob