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Re: AO-40 S-Band Test

Jesse and All,

I copied the beacon this morning with a good strong signal.  It peaked my
S-meter (a really bad measurement) up to about 6.  The fast fading was very
pronounced - enough to make error free telemetry very difficult.  The doppler
'wobbulation' was also very pronounced.  At this time (Jan. 14, 2001 17:12
UTC) I am still able to here the satellite - barely above the noise.)  I am
using a Myers 24 dB linear polarization parabolic, a DEMI 13LNAK preamp at
the antenna, a DEMI down convertor, an ICOM 275H as the IF, and G3RUH modem.

Jesse, I think you will benefit from a good preamp mounted at the antenna.
Unfortunately AO-40 is pointed at a very poor angle and the signal is mostly
very weak.  I have not been able to copy good telemetry, just a few error
free blocks.

73's de Rich @ WC8J


Jesse Morris wrote:

> Good morning to all.
> Tried some more experiments with the S2 beacon on AO-40 today with mixed
> results.  Pass was not nearly as good as last Sunday.  I acquired the
> beacon late.  Elevation was about 8 degrees and the squint angel was
> around 30 degrees as indicated by IT and kep set #23.  The signal was
> right in the noise when I first heard it using the same setup as last
> Sunday.  I switched to the antenna with the conventional matching (vice
> the grounded link match in the W0OQC design) and could not hear the
> beacon at all.  After a couple of minutes the signal got a little
> stronger and I could hear it with the conventional antenna but the
> grounded match antenna was better.  I can't think of any reason for that
> except that I just haven't gotten the other antenna matched correctly.  I
> still don't have a way to adjust the match so I am trying to use the
> "cook book" approach.  At a squint angle of about 35 degrees I switched
> to a  LHCP antenna but heard nothing.  Just about the time I thought the
> signal was getting stronger (somewhere between a squint angles of 38 and
> 40 degrees) I lost the signal.  I thought it happened as a result of
> switching the cable between antennas but I never was able to hear the
> signal again.  As I'm writing this I begin the think that maybe the trunk
> of the medium sized oak tree in the front yard might have been there
> culprit.  If so,  I gave up too quickly.  I need another shot at a little
> better pass than we had this morning.
> As a reminder, I am using a Drake converter with only the two IF coils
> and caps removed followed by a down converter to ten meters.  No pre amp.
>  I would appreciate hearing from anyone who copied the beacon this
> morning concerning the strength of the signal.
> 73 de Jess - W4MVB
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