[amsat-bb] Re: ARISSSat-1 Help

George Henry ka3hsw at att.net
Sat Aug 6 06:27:43 PDT 2011

In HRD, do you have the transponder set up as inverted (RX mode USB, TX mode 
LSB, Linear Inverting Transponder button clicked)?  If you have it set up right, 
the TX frequency should track in the opposite direction as you tune the RX.

It is normal for the TX frequency to be lower in the early part of the pass and 
higher later:  you are trying to maintain a constant frequency received at the 
satellite, and the motion of the satellite ADDS to your uplink frequency as it 
approaches you, and subtracts from it as the satellite moves away.

George, KA3HSW

----- Original Message ----
> From: Bill Photinos <Bill at photinos.com>
> To: amsat-bb at amsat.org
> Sent: Sat, August 6, 2011 8:02:51 AM
> Subject: [amsat-bb] ARISSSat-1 Help
> Tried to work the 1201Z 06AUG2011 pass of ARRISSat-1 from FM26 this 
> morning without much luck.  I have been successfully working the FM 
> birds for a while but this is my first attempt with a linear bird.  I 
> was wandering if someone with a similar setup could verify my settings?
> Equipment as follows:
> Icom IC-910H
> Gulf Alpha  2M/70cm dual band yagi.  2M->6 element 70cm->8 element antenna
> LVB tracker box connected to a Yaesu G-5500 Az/El Rotator controlled by 
> Ham Radio Deluxe.
> In HRD I set the following:
> Rx - Center of 145.930 USB
> Tx - Center of 435.750 LSB
> I set it to control doppler on *both* freqs.
> I am pulling the keps from Celestrak now.
> This morning's pass was to North->South and to the West of my 
> location(FM26au).  I noticed that the Rx was always being set lower than 
> the center freq, and the Tx was lower before max elev and higher after 
> Max elev.  I had about a 9min window.  About a 1/3 of the way into the 
> pass I thought I heard some garbled voice.  In the last 1/4 of the pass 
> I definitely was hearing some CW.  I can post the recorded .wav file if 
> necessary.
> Would greatly appreciate any help.
> 73,
>   Bill - W4RVN

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