[sarex] Re: ARISS events

Ransom, Kenneth G. (JSC-OC)[BAR] kenneth.g.ransom at nasa.gov
Fri Mar 16 12:49:36 PDT 2007

Yes the ground stations compensate for Doppler on the uplinks and
downlinks during the contact. They use any of the standard methods to
adjust for the +/- 3.3 KHz Doppler. Manual control via a prediction
table, preprogrammed memories or computer control of their rig. 

Kenneth - N5VHO

-----Original Message-----
From: Roger Kolakowski [mailto:rogerkola at aol.com] 
Sent: Friday, March 16, 2007 1:48 PM
To: Ransom, Kenneth G. (JSC-OC)[BAR]; sarex at AMSAT.Org
Subject: Re: [sarex] ARISS events

Sorry Ken and Tim...

I guess my real question should have been..."do the school ground
stations compensate for doppler on their uplinks during their contacts?"


----- Original Message -----
Subject: RE: [sarex] ARISS events

ISS is just like any other satellite when it comes to Doppler. The
satellite does not adjust its frequency. ISS transmits on 145.80 and
each ground station adjusts their Doppler according to their relative
position to the ISS.

Kenneth - N5VHO

-----Original Message-----
Subject: Re: [sarex] ARISS events

Hi Ken...

Just a quick question that came to mind after today's school contact...

Do the astronauts know how to or do they adjust for doppler during the
contacts? I know from the ground station that we might be dealing with
+/- 8 kHz up there...do they have "steps" built into their radio?

Thanks and keep up the good work!


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