---- Original Message ----- From: "David 4X1DG" 4x1dg@iarc.org To: amsat-bb@amsat.org Sent: Sunday, May 13, 2012 6:30 PM Subject: [amsat-bb] Circular polarization
Is a UHF circular polarization antenna needed for the current operational satellites? I am planning some work on my antenna system and wonder if the CP is needed, or actually, deteriorate the signal by 3dB if the satellites are using linear antennae??
The best option would probably be a rotatable antenna, a sat will never be fully horizontal vertical or circular, sometimes it even makes a difference when you flip 180 degrees.
-- 73 Andre PE1RDW
Hi Andre, PE1RDW
I agree.
A rotatable boom by 90 degrees is a very good option for a linear antenna because in a certain moment a sat can send to you a polarization between linear or through circular i.e. an elliptical polarization that can be matched by turning the antenna over the boom.
BTW since the polarization changes very rapidly the speed of rotation of the boom must be very fast, let say maximum 10 seconds or less to rotate from 0° to 90°
73" de
i8CVS Domenico