[amsat-bb] Re: ISS: 143.625 downlink 2x (also by D700 ??):

Ransom, Kenneth G. (JSC-OC)[BAR] kenneth.g.ransom at nasa.gov
Thu Oct 16 04:56:34 PDT 2008

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

Kenneth - N5VHO

-----Original Message-----
From: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at amsat.org] On
Behalf Of Henk, PA3GUO
Sent: Thursday, October 16, 2008 6:02 AM
To: amsat-bb at amsat.org
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
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 ?

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 AMSAT-BB at amsat.org. Opinions expressed are those of the author.
Not an AMSAT-NA member? Join now to support the amateur satellite
Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb

More information about the AMSAT-BB mailing list