Thursday, August 11, 2011

New UHF Satellite Frequency?? Update

At 1340 UTC I received voice comms on a possible new satellite frequency -- 261.420 MHz nfm. had two OMs in a foreign language chatting and then disappeared around 1345 UTC. Just had another hit at 1402 UTC so this suggest either a geostationary or Molniya orbit high flyer.

Audioboo: Milsat Downlink 261.420 MHz 8-11-2011 #uhf #milsat #downlink via @Audioboo

There are no known US UHF milsat assignments on this freq. Closest US Mil freq is 30 kHz higher on 261.450 MHz, an old Fltsatcom Bravo wideband channel. This is an outside possibility since we never did get a real handle how wide these transponders really were. Some thought that at the band edge of these supposed 500 kHz wideband transponders that they did extend below the band edges, but I never saw anything solid.

So is this the bottom end of a 500 kHz wideband transponder or ? From tracking that I have been able to dig up it doesn't look like either Fltsatcom 7 or 8 as I do not have any visibility to them from here right now.

At 1410, I'm getting some apparent shift in freq to 261.419 MHz. This is probably from the ground stations and not doppler. Trying to record some audio for posting and help with language/content. As I type this update just had another weak hit at 1409 UTC.

Our good friend Paul Marsh from sent me the following SDR plot. He thinks I have a Fltsatcom wideband transponder. According to Paul we have 7 pirates up on this one so that is probably what I heard.

Will still maintain a watch for further comms until I positively lock down the satellite.