[amsat-bb] FD Postmortem: was "a cheap LEO tracker for single op"

Bill (W1PA) w1pa at hotmail.com
Wed Jun 26 11:35:59 PDT 2013

A quick follow-up and some questions.

I made it to the FD site about 11pm local. 
Schedule had two passes of SO-50 (1am and 3am) and two 
passes of AO-7 (at 4am and 6am local).

Let's focus on AO-7. I had my FT-847, two 10 ft lengths of coax, 
and the trusty Arrow dual-band.  
I had my Ubuntu netbook with gpredict and a printed frequency list.
I ran AO-40 full manual back in the day (no computer 
assist or Doppler) --I can do this, right?:

AO-7 (B) 432.125-175  up, 145.975-925 down.

Load 432.125 on the main VFO, and 145.975 (USB) on the secondary. Set Sat mode, (tracking REVERSE)
Hear the bird great --   can’t find my downlink. Nada.  Voice or CW.
Confirmed 432 TX and power out with a meter --  ran up to 30 watts in. Moved the sub-tune up and down on the RX side for Doppler (at least 15khz each side).  Coax was connected correctly.

Nothing on the next pass either....  excellent hearing, can’t find myself.  Bird is directly overhead. Epic fail.

So what did I do wrong?  Did I have a de-sense issue because of the crossed yagi?  Enough power? What sideband should the uplink have been (LSB, correct)? Even if it was wrong, I should have heard CW, right?

Bill  W1PA

More information about the AMSAT-BB mailing list