----- Original Message ----- From: "Luc Leblanc" lucleblanc6@videotron.ca To: aa5pk@suddenlink.net Cc: amsat-bb@amsat.org; eu-amsat@yahoogroups.com Sent: Saturday, September 19, 2009 10:38 AM Subject: [amsat-bb] A432-20T AXIAL RADIATION???
I want to thank's Glenn AA5PK who provide me with the antenna manual. When reading it i discover something new "axial radiation" the matching line can be made for LHCP and RHCP using RG-59 and RG-58 combination for delay/matching lines and two RG-59 for delay/matching lines to produce this "axial radiation"?
Hi Luc,VE2DWE
Two RG-59 are to produce only the matching between two 50 ohm antennas in parallel and a 50 ohm feed line but not delay is generated so that the axial radiation is a linearly polarized wave.
Is this gives both horizontal and vertical polarization at the same time?
The horizontal and vertical polarizations are both present but they are two components that combines each the other to generate a resultant wich is 1.41 greater in amplitude and this combination of two components and one resultant at the same time is called axial radiation. If you mount the elements in X configuration the above resultant can be a vector horizontal or vertical depending on how you have oriented the arms of the gamma match. If you mount the elements in a + configuration the above resultant can be a vector at 45° or 135° depending on how you have oriented the arms of the gamma match. Following the schematic diagram in the manual for axial radiation you get at the same time a vertical and a horizontal components while the resultant as per Pitagora theorem is oriented at 45°
If it's the case it's could be a way to counteract the polarization change eg; having to manually rotate the antenna. Just note they don't called it "polarization" but "axial radiation"
In the axial radiation the maximum radiated power lies in the resultant vector wich is the amplitude of a componenent vector multiplied by 1.41
In conclusion the axial radiation is a way to get at the same time two crossed linear polarization components with a resultant linear radiation in between shifted by 45° or 135° wich amplitude is 1.41 time greater.
Luc Leblanc VE2DWE Skype VE2DWE www.qsl.net/ve2dwe DSTAR urcall VE2DWE WAC BASIC CW PHONE SATELLITE
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i8CVS Domenico