Re: [amsat-bb] ao-40 antennas

["John Wilcox" <ns1z@xxxxxxxx>]

I agree with Al. I have been using the Andrew BBQ dish and thought I was
doing fine. Last night, however, I finally found the activity on S1 that was
reported on the BBS. I pointed off with the dish ( a converted PrimeStar
unit) and was able to easily see a 1 to 1 1/2 S unit change in the noise
floor. Before experiencing this first hand, I would have said the others
were telling a whopper!. My 5 turn helix feed, by the way, is made from 1/4"
copper tubing which was left over from the installation of my second oil
tank (gets fairly cold here in Maine during the winter...).

Circular polarization is definately the way to go. Now, how am I going to
put that Kultronics 3.0 meter dish to use...

----- Original Message -----
From: Al Lawler <alawler@us.oracle.com>
To: Richard Donner <rdonner@earthlink.net>
Cc: <amsat-bb@AMSAT.Org>
Sent: Wednesday, August 08, 2001 12:28 PM
Subject: Re: [amsat-bb] ao-40 antennas


>
>   I'm using the Phillips-tech 24dbi(Linear) bbq dish
> with a DEM preamp and a drake 'easy-mod' converter
> with great success.  I can definately hear as well
> as the vast majority of people on the birds (and quite
> obviously better than many.).
>
>   My only concerns about the dish are:
>
>   1)  The feed pigtail has about 3 feet of RG-213 (terminating
>       in an N connector), which obviously has a
>       negative effect on the ultimate noise figure.
>
>       (I've been thinking about trying to just
>       cut off the unnecessary cable, but am not
>       convinced that the cable loss I'd save would
>       offset the losses of a hand-soldered n connector,
>       and unfortunately, the feed itself is sealed
>       in plastic making it impossible to mount the
>       preamp without at least some pigtail.)
>
>
>   2)   I STILL don't hear as well as the people using
>        1-meter circular dishes.  This was apparent last night
>        as my s1 sqint ingle got up to 15 degrees or so,
>        and I was struggling to listen in on QSO's where
>        both parties obviously heard each other just
>        fine, despite similarly poor squint angles.)
>
>        I've caught myself on one or 2 occasions
>        accidently cq'ing on top of a very weak QSO.
>        (There is a LOT of activity on ao-40 at very low
>        signal levels.)
>
>   IN short, the phillips dish is a quite good antenna,
>   and my setup is as good as (or better) than most ao-40
>   users, but there are many people down by the noise-floor
>   who are hearing substantially better than me.
>
>   -al
>   WB1BQE
>
>   FT736r
>
>   2x9 el cushcraft (dummy-load) yagi uplink
>   Phillips spg-36 bbq dish -> DEM 13ulna -> drake
>
>
>
> Richard Donner wrote:
> >
> > Would people like to comment on the following antenna links for ao-40
> > antennas for 2.4 ghz
> >
> > http://www.hyperlinktech.com/html/products/antennas_2400.html
> > http://www.hamtv.com/pdf.files/Cat4.pdf
> > http://www.hamtv.com/cat97.html
> > http://www.phillips-tech.com/main.asp?page=page6.asp
> > http://www.ssbusa.com/ao40dishes.html
> > http://www.downeastmicrowave.com/Antennas.htm
> >
> >
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