Hi, think I finally found out why there was not as great a difference on the LHCP compared to RHCP or so I thought and yes it was operator error (you guys already knew that I think hi). Problem was I was using NOAA satellites as my signal source for a RHCP and when I switched to LHCP could still hear them well. Truth of the matter is the signal here on RHCP is massive around 59+40db on a normal pass, when I switched to LHCP the signal was still BIG (59). So the truth of the matter is, there is a huge difference to my RHCP and LHCP but I should not have used such a large signal as a reference source. I realized what might be the error and checked it by sending my 14 year old son Cameron (2E0BAU) out on a 10 mile bicycle ride with a Yaseu VX2r handheld and a small yagi (similar to arrow). having got to a nice high spot, he pointed the yagi in my direction, he then spun the yagi slowly in a RHCP everything was fine (around 0.1watt output from VX2r) but when he spun the yagi in the wrong sense he was a very poor signal. So now I have got that sorted, I am happy but sadly Cameron is not, very heavy downpour on his way back home on the bicycle, got very wet! Still its all in the name of science! regards Gus M0IKB
----- Original Message ----- From: "Angus" angus@young5769.freeserve.co.uk To: amsat-bb@amsat.org Sent: Wednesday, August 20, 2008 6:32 PM Subject: [amsat-bb] re polarity control (woops!)
Hi,
snipp
I realized what might be the error and checked it by sending my 14 year old son Cameron (2E0BAU) out on a 10 mile bicycle ride with a Yaseu VX2r handheld and a small yagi (similar to arrow). having got to a nice high spot, he pointed the yagi in my direction, he then spun the yagi slowly in a RHCP everything was fine (around 0.1watt output from VX2r) but when he spun the yagi in the wrong sense he was a very poor signal.
Hi Gus, M0IKB
When Cameron spun the linear yagi slowly in a RHCP and in a LHCP direction he is not generating a RHCP or a LHCP wave but the wave is still linearly polarized on several diffent angles.
The test that you have made to measure the copolarization of your antenna make no sense because for 2 meters Cameron should have ben able to spun the boom of his linear yagi at 145 million revolutions per second by hand ......HI ! !
Instead Cameron must transmit with a switchable RHCP / LHCP antenna while you measure the difference of signal strenght RHCP versus LHCP at your antenna.
The following article explaining the above matter is recommended and is available in zipped files on request off line to everyone is interested on it.
"The Advantages of Circular Polarization" by K4KJ Sept-12-1975 ARRL Technical Symposium, Reston Virginia
regards Gus M0IKB
Best 73" de
i8CVS Domenico
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