![]() ![]() The two repeaters are operated alternately by means of a timer arrangement, but repeater selection and output power control can also be accomplished by ground command. Approximately 50 watts EIRP is required to produce 3 watts of repeater output at a range of 2,000 miles assuming a polarization mismatch of 3 db. A 200 milliwatt telemetry beacon on 145.975 provides telemetry data. Developmental versions of this repeater have flown in high-altitude balloon experiments in Germany, and aircraft flight tests of the repeater prototype unit. Since the uplink band in shared with the radiolocation service, an experimental pulse suppression circuit is incorporated in the repeater to reduce the effects of wideband pulsed radar interference in the uplink. ![]() This repeater has an uplink from 432.125 to 432.175 MHz, and a downlink from 145.975 to 145.925 MHz. It employs an 8-watt PEP power amplifier using the envelope elimination and restoration technique to maintain linear operation over a wide dynamic range with high efficiency. The second repeater, constructed by AMSAT Deutschland e.V., AMSAT’s affiliate in Marbach, West Germany, is a 40-kHz* bandwidth inverting linear repeater. This corresponds to an EIRP from the ground of 90 watts for a distance to the satellite of 2,000 miles and a polarization mismatch of 3 dB. Approximately -100 dBm is required at the repeater input terminals for an output of 1 watt. A 200 milliwatt telemetry beacon provides telemetry data on 29.502 MHz. This non-inverting transponder receives uplink signals between 145.85 and 145.95 MHz, and retransmits them between 29.4 and 29.5 MHz on the downlink. The first repeater is a higher power, two-watt version of the one-watt two-to-ten meter linear repeater that flew on the OSCAR 6 mission. Two types of communications repeaters are aboard the spacecraft, only one of which operates at a time. The spacecraft is solar powered, weighs 65 pounds, and had a three-year anticipated lifetime at the time it was launched, but it has far outlived this expectation. Spacecraft DescriptionĪMSAT-OSCAR 7 contains two basic experimental repeater packages, redundant command systems, two experimental telemetry systems, and a store-and-forward message storage unit. The Mode-B transponder was the first using “HELAPS” (High Efficient Linear Amplification by Parametric Synthesis) technology was developed by Dr. The Mode-B transponder was designed and build by Karl Meinzer, DJ4ZC and Werner Haas, DJ5KQ. The 2304.1 MHz was never turned on because of international treaty constraints.įour radio masts mounted at 90 degree intervals on the base and two experimental repeater systems provided store-and-forward for morse and teletype messages (Codestore) as it orbited around the world. Built by a multi-national (German, Canadian, United States, and Australian) team of radio amateurs under the direction of AMSAT-NA. Octahedrally shaped 360 mm high and 424 mm in diameter.Ĭircularly polarized canted turnstile VHF/UHF antenna system and HF dipole. and was the second Phase 2 satellite (Phase II-B). AO-7 was launched piggyback with ITOS-G (NOAA 4) and the Spanish INTASAT. Hamfests, Conventions, Maker Faires, and Other EventsĪMSAT-OSCAR 7 was launched Novemby a Delta 2310 launcher from Vandenberg Air Force Base, Lompoc, California.Tom Clark, K3IO, Memorial Space Symposium and Annual General Meeting 40th Anniversary AMSAT Space Symposium & Annual General Meeting.FoxTelem Software for Windows, Mac, & Linux.South Africa AMSAT Satellite Communication Achievement Award.AMSAT Satellite Communication Achievement Award.Orbiting Satellites Carrying Amateur Radio.Tools for Spacecraft and Communication Design.Notification of Trademark, Copyright and Other Proprietary Information. ![]()
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