I guess the two radios could be the ISS and the Soyuz? They might have been doing some comm. checks in the Soyuz preparing for the undock and deorbit next week.
Kenneth - N5VHO
-----Original Message----- From: Henk, PA3GUO [mailto:[email protected]] Sent: Thursday, October 16, 2008 7:29 AM To: Ransom, Kenneth G. (JSC-OC)[BAR] Cc: [email protected] Subject: RE: [amsat-bb] ISS: 143.625 downlink 2x (also by D700 ??):
Hi Kenneth !
Sorry I did not express myself very clear - apologies.
What I think I heared were two (2) signals from ISS at the same time (both at 143.625): 1) the Russian VHF system (voice) 2) a second radio onboard the ISS, I guessed the D700 (constand carrier)
Reason for posting: I hear often 1) and feel familiar with type of comm's on that channel. However, I assume that IF the second signal came from ISS, that it would have been the D700 - and that the D700 would not be expected to transmit on that frequency (also assuming the SSTV VOX circuit was the cause of the silent carrier to be transmitted)
That's all :-) Henk
Sounds like the Russian VHF comm. system which has a multi polarity
antenna array. They may have locked the PTT in
anticipation of a ground pass over Moscow and you were hearing
background noise from within the ISS.
Kenneth - N5VHO
-----Original Message----- From: [email protected] [mailto:[email protected]]
On Behalf Of Henk, PA3GUO
Sent: Thursday, October 16, 2008 6:02 AM To: [email protected] Subject: [amsat-bb] ISS: 143.625 downlink 2x (also by D700 ??):
To whom this may concern (Kenneth N5VHO ?):
Thursday 10:45utc pass over Europe:
With the very latest keps I monitored both 145.800 and 143.625. Late in the pass, a carrier appeared on 143.625. Also I heared now and then voice from another source (distorted)
through that.
Initially I believed this was a local station transmitting on 143.625.
But: switching between HOR/VER/LHCP/RHCP gave exactly the same ratio of that carrier versus the voice/other signal... they must have identical polarization: too much coincidence to me.
Then: the carrier faded down fast in the last 2 degrees elevation,
like the ISS 145.800 also always does: the
carrier must have come from ISS: I guess the D700 also has 143.625 programmed ?
Conclusion: I suspect that maybe the Kenwood D700 onboard was transmitting on 143.625 and at the same time the astronauts tried via the other
radio to reach Moscow (like they do every day).
Most likely Moscow also could not hear the 2nd radio, as the carrier
was strongest.
Henk, PA3GUO The Netherlands
Sent via [email protected]. Opinions expressed are those of the
author. Not an AMSAT-NA member? Join now to support
the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb