[amsat-bb] Re: Tranzit-B telemetry system on ISS

MM ka1rrw at yahoo.com
Mon Mar 16 15:54:59 PDT 2009

The Russians have a few transmitters in the VHF band.
I am not at liberty to release the exact frequencies.

One of the commercial radios on ISS is a FM Repeater.  The downlink is just below the amateur radio 2-meter band and the uplink is in the aircraft band.  

Once a month or so they leave the VHF-1 radio running constantly to test the ground stations ability to access this system in case of emergency.  If the ISS ever tumbles, it will loose satellite lock and will have to rely on VHF communications line-of-site links until stable flight is reestablished.  The Mir Space Station tumbled on several occasions.  

Sometimes you can hear VHF-1 while ISS is passing over the USA.  When the repeater mode is active you can hear American aircraft signals being re-transmitted over the ISS commercial repeater.

It seems that there is no interested in making the Russian ISS repeater input channel a clear channel in the USA.

When VHF-1 was active on Mir, it would immediately de-sense the Kenwood TM-733 and the TM-V7A.  To correct this problem I installed a custom built filter from DCI to notch out the offending VHF-1 transmission.  I have not been able to confirm if ISS has the same issues.

73 Miles WF1F

--- On Mon, 3/16/09, andy thomas <andythomasmail at yahoo.co.uk> wrote:

> From: andy thomas <andythomasmail at yahoo.co.uk>
> Subject: [amsat-bb]  Tranzit-B telemetry system on ISS
> To: "amsat" <amsat-bb at amsat.org>
> Date: Monday, March 16, 2009, 6:08 PM
> I've just come across the following interesting
> references on space ref to what seems to be a VHF telemetry
> channel (bio/medical monitoring?)
> "...including VHF/voice & biomedical electrode
> belt and *telemetry hookups via the BSS (later by the
> wireless in-suit Tranzit-B radio telemetry system) for vital
> signs and equipment monitoring".
> http://www.spaceref.com/news/viewsr.html?pid=30763
> and:
> " [The suited run requires wireless Tranzit-B suit
> radio telemetry on both semisets (activated: 2:56am) and
> temporary deactivation of the Russian VHF channel 1 (Very
> High Frequency, Russian: UKV1, for ultra-shortwave) to avoid
> interference from extraneous radio stations to the Orlans
> while over Russian ground stations (RGS, DO 3/4).  All EVA
> preps were monitored by the ground via audio, the reason for
> the early morning time of the training run.  Tranzit-B TM
> was turned off at ~3:10am EST.]"
> http://www.hq.nasa.gov/osf/iss_reports/reports2008/12-19-2008.htm
> My questions are: what is the TRANZIT-B TM system,  how
> close is it to the 2m channels, what is the TLM data
> modulation and breakdown? 
> 73 de andy G0SFJ
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