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@aol.com To: "Clint Bradford" clintbrad4d@earthlink.net; amsat-bb@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@earthlink.net To: amsat-bb@amsat.org; amsat-bb@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@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite
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Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb