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Re: AO-40



I'm trying to evaluate my system with severe limitations, and could use some
help.

Antenna: HyperLink Tech 39" bbq style dish with dipole feed. (8 deg 3 dB
beamwidth)
DownConv: SSB UEK-3000 fed directly into the antenna pigtail of about a foot
135' RG8/X to radio
Radio: FT-847

Ground testing, no way to be sure of pointing at anything but the sun.

Results:

Sun Noise: exactly as reported below: "a little under 1 s-unit of noise or
about 2 segments of the s-meter lit, sometimes flickering".

This seemed to indicate to me that I'm hearing pretty well...is that true
from what I'm experiencing, or is it just wishful thinking on my part?

Next:

The by guess and by golly pointing I'm doing is not working out well at all.
I hear the bird very strong with severe doppler at perigee, of course.
However, I never got signals worth a darn the last two times this weekend
when I checked, with squints of 8 deg. Very discouraging.

My question:

Am I hearing enough sun noise to indicate that my system is working ok, and
my problem is that I'm never really pointed at the bird? I want to make sure
everything is "jake" before going up on top of the tower. My only "reliable"
signal source is the sun. Am I hearing enough sun noise to put the system on
my tower? On the tower I will have full az/el control that can be peaked for
accuracy.

On the ground testing, I have no idea of my pointing other than VERY roughly
and I have to run back and forth to the shack, adjusting azimuth crudely and
probably a little better accuracy with elevation, by placing an inclinometer
on the bar that supports the dipole feed and then removing it when I try to
hear the bird.

I can accurately position the dish at the sun by centering the shadow of the
dipole equally about the point where the dipole feed support bar enters the
back of the dish. I just can't get any confidence that I'm pointing at the
bird...and if I am...my system isn't working worth a darn.

Any and all comments are appreciated as I won't have people that can
repeatedly go up and down that tower once we make the move.

I'm beginning to experience all sorts of paranoid ideations ...mostly
centered around the dish, which I believe should work quite well...spec'd at
24 dB gain and worked wonderfully as a wireless internet antenna...no active
components in it...just 39 inches wide with a dipole feed and LMR-400 one
foot pigtail terminating in a female N connector. I'm not shooting through
any leafy vegetation or trees when I'm evaluating the performance.

HELP PLEASE!

If it's the antenna, what recommendations would you have?

73,

hasan, N0AN
schiers@netins.net

----- Original Message -----
From: "Tim Cunningham" <tim_cunningham@mindspring.com>
To: <ve2me@AMSAT.Org>; <amsat-bb@AMSAT.Org>
Sent: Sunday, July 15, 2001 9:48 AM
Subject: Re: [amsat-bb] AO-40


> >
> > has anyone heard the beacon
> > on AO-40?
>
>
> Yes, we heard it very nice last night in the Southeast USA.
>
> I caught the bird at 28 degrees elevation when it was at 20,000 km
> down range around MA19.  I was able to copy over 548 good CRC
> frames by manually tuning from time to time as it got out to 50,000 km.
> That was the point where the CRC's started to fail and at 51,000 km they
> were all bad at that point.
>
> I am using a TranSystem AIDC-3733 mounted on a 3' bar-b-cue
> parabola type antenna with the following mods:
>
> 1. Stub filter unsoldered
> 2. Murata DFC22R44P084BHD mounted on one of Bob's (K5GNA)
>     circuit boards.
> 3. Crystal changed for 2400 MHZ at 144 MHz
>
>
> On my FT-847 I get a little under 1 s-unit of noise or about 2 segments
> lit with the second segment flickering at times.  The signal last night
> from AO-40 was around S6 solid when I first tuned to it at MA19 at
> 21,000 km down range.  When the signal got down to S3, that is
> when I started losing the good CRC frames.
>
>
>
>
>
> 73's,
>
> Tim - N8DEU
> Huntsville, Alabama
>
>
> ----
> Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
> To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
>

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