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

[Art McBride]

Aircraft transmissions are AM to allow detection a weaker signal that may
come from a distressed aircraft. A carrier 30 dB lower will still produce a
whistle allowing the controller to ask the other aircraft to stand by to
copy the weaker signal.

Art, KC6UQH 

-----Original Message-----
From: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at amsat.org] On
Behalf Of Nate Duehr
Sent: Monday, March 16, 2009 5:27 PM
To: 'amsat'
Subject: [amsat-bb] Re: Tranzit-B telemetry system on ISS

How are the "American aircraft signals" which are all AM, being rebroadcast
in any intelligible way by an FM receiver?

The only aircraft that MIGHT transmit with FM, are military aircraft.  And
rarely in the clear or without frequency-hopping spread spectrum technology
involved.   (And that's not really FM, so to speak -- nor copyable through
the repeater you're describing.)

I smell something wrong here with your information, or there's more to the
story.

Nate WY0X

-----Original Message-----

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.

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