[amsat-bb] AO40 portable

[Estes Wayne-W10191 <W10191@xxxxxxxxxxxx>]

Howard wrote:

Indeed, I ran a demo station on Sunday myself on AO-40.
We had a slightly different result, as squint was luckily on our side.
Indeed, on a couple of occasions we were in a pileup situation.

I wonder what the AGC
suppression was running at, and if it was being activated by radar? The
reason I mention this is that on an almost identical pass eight days earlier
on Saturday 16 March using the same equipment, I found the bird to be quite
deaf in comparison to Sunday 24 March. Because I'm operating portable I
don't have telemetry running, so I can't tell 'on the fly' what the AGC is
running at. Certainly the stations making it in on the Saturday were all on
L band.

Wayne replies:

My U uplink on 24 March was weaker than it was the previous times I used the portable uplink antenna.  But on 24 March I was operating near apogee with squint near 20 degrees.  Signals for me were BETTER on 16 March, but then I was operating at shorter range with smaller squint.

I had considerable desense with the portable setup.  I could generally only hear myself during the echoes after I quit talking.  But I could hear other stations fairly well.   Most of the stations I worked on the 24th were using the U uplink, but they were all using bigger antennas and some were running more than 50W.

I frequently notice a "stairstep" pattern in downlink signal strength.  Everything is fine for a while, and then the signal suddenly drops a couple S-units for a few seconds.  I suppose that could be caused by radar.  Sometime it's also caused by a nearby LEILA attack.  I have sharp IF filtering, so sometimes I am on the edge of the LEILA notch when I can't hear the LEILA siren.

Wayne Estes W9AE
Mundelein, IL, USA
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