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Re: AO-40: Going "LIVE" - Saturday!!!!

Peter Guelzow wrote:

> Dear All,
> Experimental transponder operation will start on Saturday morning May 5th at
> approximately 08:00 utc when the U-band and L1-band uplinks will be connected
> to the S2 transmitter passband in the Matrix.

Well, this sure got me motivated to get my S-Band downlink operational!  I've had
two different downconverters for a couple months (a Drake and a Trans-systems),
but had not done anything with either one of them.

Friday evening after work I mounted the trans-system into one of my spare dishes
(an old 2 x 3 foot PrimeStar DSS dish).  Got it mounted on the El/Az rotor by
moonlight and a flashlight (dang I was glad the moon was bright last night!).
Kludged up a bias-T just before AOS at about 2300 local time (0600z).  Listened
for an hour and never heard the beacon so I went to bed - rather disappointed).

This morning I tried again with the bird much closer and still did not hear
anything.  That's about when I discovered that the DC buss I had grabbed for
power was not energized because it's powered only when I have the ATV station
powered up - ARGH!!!!  After turning on that power supply, I heard life on the
S-band downlink!  Dialing across the IF with a Icom PCR-1000 (running under
Windows 2000 it works fine BTW) I heard several weak conversations, but I wanted
to get the beacon to check to see how closely I had gotten the offset feed dish
to pointing to where it was supposed to be.  I found the beacon OK and after a
few minutes of moving the antenna up / down, and left / right I decided that I
had done a pretty good job (I think I'm off about 2 degrees vertically).  I dial
down to the bottom of the passband and send some dits and dahs on the UHF uplink
and can't find myself.  About that time I swap over to the AMSAT channel on the
IRC too see people saying that the transponder had shut off (on schedule).  I
guess I slept too long.  By next time I'll clean up the Bias-T and get a better
feed on the dish - I think I'll try a small helix so I can get CP.

Jim Walls - K6CCC
626-302-8515    FAX  626-302-7501
AMSAT member 32537 / WSWSS member 395

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