----- Original Message ----- From: "Edward Cole" <kl...@acsalaska.net> To: "Douglas Quagliana" <dquagli...@aol.com>; "amsat" <amsat-bb@amsat.org> Sent: Thursday, April 15, 2010 11:49 PM Subject: [amsat-bb] Re: Arecibo and circular polarization using cheap yagis > > Or you can split the feedline equally if one > antenna is spaced 1/4 wavelength ahead of the other. The relation of > the fed elements determine whether you get RH or LH CP. The center > conductor is connected to one side of the fed element (this is called > the + side). If the antenna to the rear (or not with extra feedline) > is vertical with "+" straight up and the other antenna has its "+" > element pointing to the right, you get RHCP. Reverse it and you get > LHCP.
> 73, Ed - KL7UW, WD2XSH/45 Hi Ed, KL7UW Please find here a necessary amendment to your statement: We assume that you are looking from the rear of the antenna in direction of propagation and one antenna is spaced 1/4 wavelenght ahead of the other. If the dipole of the rear antenna is vertical with "+" straight up and if the dipole of the front antenna is horizontal and has its "+" element pointing to the left then you get RHCP. Reverse it and you get LHCP In a separate email I have sent to you a drawing showing how two linearly polarized components shifted 90° one to the other adds togheter to generate a circularly polarized wave but I can send the same drawing to everybody need it. > For antennas in the "X" configuration (back antenna "+" up and > to the left, front antenna "=" up and to the right for RHCP. If the signe "=" is a typing mistake and you means " - " (minus) then your statement is correct. 73" de i8CVS Domenico _______________________________________________ Sent via amsat...@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
