Hi Ron, W5RKN
The X configuration is the best if you use a metal-boom while the X or + configuration can be used indifferently if you use an insulated boom like fiberglass as demonstrated with experiments by WA5VJB
http://www.g6lvb.com/fibermetalboom.htm
In addition the X configuration is nice if you want to add V and H linear polarizations using a relay switcher for V-H-RHCP-LHCP as described into the AMSAT Journal March/April 2007 and May/June 2007
73" de
i8CVS Domenico
----- Original Message ----- From: "Ronald G. Parsons" w5rkn@amsat.org To: amsat-bb@amsat.org Sent: Sunday, May 18, 2008 11:42 PM Subject: [amsat-bb] Re: AOP-1 Circular Polarization?
Assuming the antennas you reference do produce circular polarization, radiation wise, it doesn't matter whether you mount them in an X or + orientation. The only difference would be the phase of the radiation, and you are not concerned with that. There could also be a difference between right- or left-circular polarization, but whether that matters depends on the polarization the the satellite's antenna. But X or + does not change that.
There might be some mechanical reason for an X or +, such as weather proofing, but not signal wise.
Ron W5RKN
Date: Sun, 18 May 2008 14:28:34 -0400 From: Sebastian w4as@bellsouth.net Subject: [amsat-bb] AOP-1 Circular Polarization? To: Amsat - BBs amsat-bb@amsat.org Message-ID: 2D502798-0BC1-4507-98F8-C86CEF5A7590@bellsouth.net Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes
Hello all, I'm getting ready to put back up my old AOP-1 antennas (the old Cushcraft antennas that were popular in the days of AO-10 & 13). I'm wondering whether I should follow the same procedure of cross polarization for the 440 beam? It was recommended at the time to place the antenna in an X pattern instead of the cross pattern. Also, at the time, the 2 meter antenna was suggested to be placed in the standard vertical/horizontal polarization.
Please let me know which would be the best method to use for most of today's birds.
73s de W4AS
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