Woah. Are you basically suggesting an "RFID thing" at orbital distances?
How many bits could you transmit during the brief transit through the fence? RFID is a pretty low data rate scheme, no?
Greg KO6TH
Robert Bruninga wrote:
At the SMALLSAT conference there are always presentations on modulating optical retroreflectors so very low power passive pspacecraft can still communicate telemetry by simply modulating the mirror of a laser reflector.
Can we do this at RF? Unfortunately the 218 MHz megawatt radar fence in Texas is now shut down... But, now with the amateur radio announcement of the return of the HAARP ionosphere transmitters in Alaska, there too is another high power CW system. But it is at HF. http://www.arrl.org/news/haarp-facility-to-reopen-in-2017-under-new-ownershi...
So what other HUGE power continuous RF emitters are there that transmits straight up that could be used by a passivle ON/OFF modulation of a resonant dipole in space to convey a few bits of data from a piece of wire in space?
I assume this is a 1/R^4 range equation. If I do the numbers right, a passive dipole only 200 miles up with a 10 megawatts ERP transmitter at 300 MHz could be detected by a good low noise CW receiver using a 15 dBi receive antenna at -128 dBm in a CW bandwidth? How many dB can this be improved with DSP processing?
Its just a mind game. A small matchbox size satellite with dipole antenna could at least report a few bits of data per pass over the radar beam?
I think the Airforce is re-building the radar fence but at S band. At that frequency some gain can be added with multi passive dipoles on a cubesat size satellite gravity gradient stabilized to keep it pointed down. If it could be made to work, what could we do with it?
Just thinking...
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