----- Original Message ----- From: "Rick - WA4NVM" wa4nvm@comcast.net To: "i8cvs" domenico.i8cvs@tin.it; "Luc Leblanc" lucleblanc6@videotron.ca; "AMSAT-BB" amsat-bb@amsat.org Sent: Saturday, April 17, 2010 2:54 PM Subject: Re: [amsat-bb] Re: Arecibo
You are correct about the antenna. It is a 10 + 10 element crossed yagi. At the time I put it back up a few years ago, I didn't know what the FM birds were using, RH or LH. So, I took the delay line off and hooked up both driven elements to the phasing harness "Y" in what Cushcraft called "axial radiation".
I would think this would give me the "best and worst" of everything. It would make my uplink power and downlink receive "half" of what they could be if they were phased correctly. Since I don't have any way to switch polarity, I use it this way on all the birds. I'm still very surprised I heard anything on this setup.
73,
Rick WA4NVM
Hi Rick, WA4NVM
I know very well the Cushcraft 432-20T and I have one here never used.
It is a very short antenna and it's gain is much lower than the minimum of 15 dBi required to receive Arecibo.
By the way if you have removed the delay line from the phasing arness and if you feed both dipoles with the Y arness than you get an "axial radiation" wich is a linear radiation with a maximum field at 45° and 135° if the antenna elements are crossed like the signe +
Since Arecibo comes to you circularly polarized LHCP you should be in condition to receive Arecibo not "fair at time" but much better than actually provided the gain of the 432-20T would be a little bit greater.
Tank you very much for your information.
73" de
i8CVS Domenico