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Lunar AMSATs (links)
Hello All,
Knowing that some YORF members are also amateur radio operators, I thought I'd post the following, which I just came across: Here (see: http://amsat-uk.org/2016/11/18/luna...tes-dslwp-a1a2/ , http://space.skyrocket.de/doc_sdat/dslwp-a.htm , and http://www.google.com/search?ei=VjA...1.0.0VMaj9SBrRg ) is information on the DSLWP-A1 and A2 low frequency radio astronomy satellites, which—like the RAE-B (Radio Astronomy Explorer-B) satellite—will utilize the Moon to block radio noise from the Earth. Developed by China’s Harbin Institute of Technology (HIT), each of these lunar satellites also carries a Saudi Arabian (King Abdulaziz City for Science and Technology [KACST])-developed micro-optical camera and amateur radio communications system. They will be launched in 2018 aboard a CZ-4C rocket, and (speaking of low-frequency satellites): To my knowledge, no AMSAT/OSCAR satellites using low band (160, 80, 60, 40, 30, 20, 17, 15, and/or 12 meters) beacons or transponders have ever been launched. While making two-way contacts on 160, 80, and/or 60 meters would probably be difficult—or at least intermittent—due to the ionosphere being between the satellites and stations on the ground (160 meters--1.8 MHz - 2.0 MHz--is just above the AM broadcast band), AMSAT satellites carrying at least beacons operating on these frequencies would enable interesting “topside sounder” propagation studies to be made, including using different operation modes. (Some ham radio satellites, such as the early OSCAR satellites, Dove 17, AO-10, AO-13, RS-10, FO-20, SuitSat, etc., had/have beacons that operated/operate in various modes [CW, data, synthesized voice, RTTY, etc.].) Also: While such low band transmitters (and/or transponders) would require physically-long monopole and/or dipole (or turnstile) antennas, unless physically-short antennas equipped with loading coils were used (with more powerful onboard transmitters, to compensate for the short antennas’ losses), deployable resonant-length antennas—even for very low frequencies (even lower than those of the 160 meter band)—are not difficult to mount on and deploy from satellites. Two options are the tape measure antenna (see: http://www.google.com/search?ei=eI0...1.0.l4ID6DHqsw0 ) and the related De Havilland Boom antenna (see: http://www.google.com/search?ei=YYE.....0.hQ4VE3aPgfc ), which forms a fairly rigid pre-stressed metal, circular cross-section, tubular boom when extended. Many CubeSats (and larger satellites) utilize tape measure antennas, and satellites with very long antennas (such as the RAE—Radio Astronomy Explorer—satellites and the Canadian Alouette ionospheric research satellites) have used De Havilland Boom antennas. AMSAT/OSCAR satellites with low band beacon transmitters and/or transponders could utilize either type of antenna, especially if the satellites were spin-stabilized (at least initially; they would eventually assume a downward-pointing, gravity gradient-stabilized attitude), as the centrifugal force would aid the antenna deployment. I hope this information will be useful.
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