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RE: General AO-40 Observations response


I have one of the first switches on my m2 42 element 70 cm. My instructions 
actually conflict in how to wire it. I am convinced that I did it wrong. I 
rewired the switch and now RHCP seems to be best most of the time. But some 
times LHCP works better.

Jerry, W6IHG

At 05:59 PM 11/6/2001 +0000, Gunther Meisse wrote:
>Tim, I had the same problem with my m2 30 elm uplink antenna. I have the
>switchable model, so I switched to LHCP and walllaaaa, I get in
>wonderfully!!! That is what brought me to the RH/LH question. If my M2 is
>constructed properly, LHCP works great, RHCP is down almost 30db. I need to
>run a polarization test on the antenna with a known, such as a small
>RHCP/LHCP helix to see if the polarization is backwards from the instruction
>The VSWR on my 1.2Ghz helix antennas is in the area of 1.05:1 to 1.1:1, so I
>am puzzled.
>Thanks for your info.
>Gunther Meisse
>-----Original Message-----
>From: Tim Zibrat [mailto:tzibrat@adelphia.net]
>Sent: Tuesday, November 06, 2001 1:41 PM
>To: gjmouse@neo.rr.com; amsat-bb@AMSAT.Org
>Subject: RE: [amsat-bb] General AO-40 Observations
>My observations are not quite as in-depth as yours, however I have noticed
>some similarities.
>Last weekend I worked the bird for the second time (though I've tried more
>times than that).  Both times that I worked AO-40, I received very weak
>I was using a BBQ dish for the downlink and I thought that was my problem.
>In an effort to improve my ears, I am now using a 1M offset dish with a
>patch feed and that GREATLY improved things for the downlink and the beacon
>was the strongest I've heard yet.  The squint varied from around 15-30
>degrees and the bird was approaching perigee (MA 150-220) for the duration
>of my operating time.
>I am using an M^2 30 element RHCP yagi on the uplink and the only way I
>could even hear myself is if I used the 100W brick amplifier.  Even then I
>am VERY weak on the downlink and just above the noise.  Pretty much the same
>as when I was using the BBQ dish.  The antenna SWR is reasonable and can be
>improved (around 1.8:1).  Other stations on the downlink are very strong now
>and are easy to copy.  I worked a station that is perhaps 100 miles from me
>and he was a lot stronger than I was.
>I didn't think much about it because I figured I needed to tweak my antenna
>SWR and perhaps shorten the run of 9913UF (100', brand new) to the antenna.
>That along with a better squint and I figured I would have better luck.
>But since you mentioned it, I'm wondering if that's all I have to do.  Like
>you, I'm pretty satisfied with my downlink setup, what to do to improve my
>uplink?  I shouldn't need to run 100W to get a barely discernable signal
>into the bird.
> > -----Original Message-----
> > From: owner-AMSAT-BB@AMSAT.Org [mailto:owner-AMSAT-BB@AMSAT.Org]On
> > Behalf Of Gunther Meisse
> > Sent: Monday, November 05, 2001 7:38 PM
> > To: amsat-bb@AMSAT.Org
> > Subject: [amsat-bb] General AO-40 Observations
> >
> >
> > bb members:
> >
> > I am going to share some observations on the AO-40 bird. I would like to
> > know if you concur on any of these. If you have general thoughts about my
> > thoughts, please speak up.
> >
> >       1. 70cm up link: I read that the up link is RHCP. I do
> > substantially better
> > with LHCP, using an m2 30 element crossed yagi and power from 20 to 100
> > watts TPO.
> >
> >       2. When the bird is east  of my location I do very well
> > getting great 5/7
> > 5/8 reports, and often need to power down to keep the girl in her cave.
> > When the bird is west of my location, even with a full 100 watts TPO the
> > signal stinks. I also hear very few if any other operators on
> > her. The MB is
> > still strong, S-7 above the noise floor thus, the only difference
> > (east-to-west) is the Up-link rx antenna position in relation to me.
> >
> >       3.  23 cm Up-link: I run up to 80 watts TPO on the 23cm
> > uplink always RHCP.
> > I use a 60cm dish or a 25 turn RHCP helix, all with wonderful VSWR. I can
> > barely make the bird. The result is very much like of the 70cm
> > tests when I
> > reverse the polarization. The people I have spoken to on the bird
> > (L-Band up
> > / S Down) have generally been using a liner polarized L-Band antenna. Many
> > with good results. None with as much power as I am running. Now,
> > I must tell
> > you that my helix antennas are made with 3m 1/4" copper tape. Could such a
> > design be worthless? Good tune-up, poor radiation? I do know the concept
> > works, since I have a 1/4" 3m tape feed for S-band on a 60cm downlink dish
> > and it works great.
> >
> > Your input appreciated.
> >
> > 73
> > Gunther Meisse
> > W8GSM
> > AMSAT LM: 594
> >
> > ----
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Dr. Jerry R. Pixton, PIXOS Designs LLC

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