ISS has a downlink transmitter at S-Band (~2.4 GHz) (ref: https://amsat-uk.org/satellites/hamtv-on-the-iss/) Phase4A has an uplink at S-Band (~2.4 GHz) and a downlink at X-Band (~10.5 GHz) (ref: https://amsat-uk.org/2016/06/24/phase-4a-geostationary-transponders/) AMSAT-NA is pursuing the 'Five and Dime Strategy' for future missions with C-Band (~5.66 GHz) uplinks and downlinks at X-Band (~10.5 GHz) (missions include Phase4B, Golf-T, and beyond). (ref, good place to start: https://www.amsat.org/update-on-amsat-phase-4-ground-terminal-development/)
I think historically there have been some birds that operate in the higher bands. AO-40 comes to mind with downlinks in multiple microwave bands topping out at 24 GHz (didn't miss a period there...that was twenty four gigahertz, not two point four gigahertz, though AO-40 had that too). (ref: http://www.ne.jp/asahi/hamradio/je9pel/ao40freq.htm)%C2%A0 There may be some others from the Phase 3 era with microwave uplink/downlinks, but I'm not as sure of the history there..
Many of the QB-50 downlinks included experimental S-Band downlinks (experimental in the sense of not required for the QB-50 mission, so still licensed under the Amateur Satellite Service). Many University 'beepsats' use S-Band downlinks in the Amateur Satellite allocations, though many of those operate(d) under an Experimental License.
So generally speaking, I thinks it is safe to say that YES! the Microwave satellite bands are very much alive and while there might not be a whole lot of operational stuff up there at the moment, there are many nearer term and longer term plans to continue to use those bands. The more the merrier!
-Zach, KJ4QLP
Research Associate Aerospace Systems Lab Ted & Karyn Hume Center for National Security & Technology Virginia Polytechnic Institute & State University Work Phone: 540-231-4174 Cell Phone: 540-808-6305
On 7/16/2018 5:40 PM, Eric Fort wrote:
As one goes up in frequency the Doppler goes up. That said, these would be great on a geostationary bird or something that moved much slower than the short Leo passes for most of our satellites. There are some satellites build and pending launch for amsat phase IV in geosynchronous orbit. Those launches are not cheap though and rides are much more difficult to come by. At least a few of the sats awaiting launches will use the microwave bands you speak of for their uplink and downlink. The advantage of using that spectrum is multiple MHZ of passband (think the entirety of all amateur spectrum 6m and below easily on one transponder 24x7x~365.25 to anyone in the footprint. It would be nice if amsat would provide better support for these projects and the teams that work on them.
Eric
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On Jul 16, 2018, at 5:29 AM, Samudra Haque [TTLLC] [email protected] wrote:
Hi, I am experimenting with RF carriers above 2 GHz in my lab. According to FCC and ITU tables there are several AMATEUR-SATELLITE bands allocated above 2 GHz, to very very high frequencies.
What is the status of those frequencies in terms of past, present or planned utilization on AMSAT / other satellites ?
If those bands haven't been used, should they be not used or plans to use them to protect them from being de-assigned to other services? Is there room for experimental RF super high frequency and extremely high frequency payloads on any mission to make some use of these great resource?
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