At a SmallSat conference I attended on behalf of AMSAT this summer, I was amused at the casual assumption by a researcher that 50, Five Oh, cubesats could be launched as part of an upper atmosphere project using ham frequencies for the downlinks. (They would have a lifetime of only 3-4 months.) Jan King, W3GEY/VK4GEY, who does coordination of satellite frequencies, gently but firmly brought them down to earth a bit.
On the one hand, we get new hams with interests in space communications from these projects, but on the other we need to prevent the de facto appropriation of needed frequencies. A fine line to walk.
Alan WA4SCA
The thing that worries me the most is that the de facto appropriation of our amateur satellite frequencies seems very likely if we continue along a path which keeps us from filling those slots with payloads of our own. All this complaining about cubesats and the use of amateur frequencies for telemetry is kind of pointless if we aren't using those frequencies and have no prospect of using those frequencies in the foreseeable future.
It seems to me that coordinating 50 cubesats for four months could be a tractable problem, depending on the precise nature of the signals and their orbital spacing. It's not like there is a huge number of operational amateur satellites that they'd have to avoid.
Mark K6HX