[amsat-bb] Re: Arrow Antennas twist or not

[OZ1MY]

Hi all,
I think we need some clarification.

Which satellite(s)are we talking about, when receiving with the ARROWS
antenna ?
The ARROW antenna are linearly polarised.

What latitude is your QTH ?

Regarding satellites - some have linear polarisation - some have circular
polarisation.
AO-51 has Right Hand Circular Polarisation on the "normal" repeater downlink
(435.300 MHz),
SO-50 has linear polarisation - the same applies to AO-27.

The satellites attitude are stabilised with permanet magnets. This may give
different results
depending upon where you are.

Here in Copenhagen it is a great advantage to "twist" the ARROWS antenna to
improve
the downlink signal from AO-27. We are close to the North Pole (hi)

Everyone may be right :-)

73 OZ1MY
Ib
----- Original Message ----- 
From: "Roger Kolakowski" <rogerkola at aol.com>
To: "Clint Bradford" <clintbrad4d at earthlink.net>; <amsat-bb at amsat.org>
Sent: Sunday, August 16, 2009 11:34 PM
Subject: [amsat-bb] Re: Arrow Antennas


> I will say that I can improve my 437 reception by rotating the beam...I
also
> have gotten better signals by aiming the beam at a point on the ground 100
> feet away...
>
> Why criticize? Everyone else can do anything they want to their antennas
> without me getting upset...afterall, it's not MY antenna.
>
> Now if someone wants to point me toward scientific theory, antenna
modeling
> programs, propagation theory...then I can stand up and listen...until
then,
> my best signal is most important to me.
>
> Roger
> WA1KAT
>
>
> Roger
> WA1KAT
> ----- Original Message -----
> From: "Clint Bradford" <clintbrad4d at earthlink.net>
> To: <amsat-bb at amsat.org>; <amsat-bb at amsat.org>
> Sent: Sunday, August 16, 2009 4:19 PM
> Subject: [amsat-bb] Re: Arrow Antennas
>
>
> > > ... Why are we modifying the Arrow?
> >
> > > ... Because someone's analysis says the element length is all wrong
...
> >
> > So Al Lowe's software program which he used to design these is all
wrong?
> >
> > Sorry to get defensive on Al's behalf. This thread just "feels" like a
> re-hash of an "engineer's view vs. real world results" argument. Like when
I
> was told here - by engineers - that it mattered how I twisted my Arrow
while
> working the sats. "Ya gotta take polarization into account, Clint -
there's
> a 22db difference when you turn your antenna 90 degrees - a tremendous
> performance hit if you don't take this into account ... "
> >
> > Yet in the real world of demonstrating workin' the birds, there's no
such
> performance degradation. I have hundreds of witnesses to this fact:
Capture
> SO-50 and AO-51 with the Arrow and operate TX and RX while twisting the
> antenna in different angles doesn't change the great reception and
> transmission quality.
> >
> > If you are in the market for an Arrow, I simply suggest that you use it
as
> offered to you. You will be pleased with its 2M and 440 amateur bands
> performance. And leave the modding of the elements w-a-y on the bottom of
> your "things to do" lists.
> >
> > Clint Bradford
> >
> > ----------------------------------
> > Clint Bradford, K6LCS
> > http://www.clintbradford.com
> > _______________________________________________
> > Sent via AMSAT-BB at amsat.org. Opinions expressed are those of the author.
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>
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