[amsat-bb] Re: Helix Reflector
k9qho6762 at sbcglobal.net
Fri Jun 4 18:59:38 PDT 2010
Ed - KL7UW, WD2XSH/45 said:
"You might be interested in the Helical Beam that Mike Cook designed
in 1996 for reception of the Mars Global Surveyor (MGS). He used a
10.66 inch diameter loop Reflector. "
I have built two 70 cm helix antennas using the loop reflector. The first one was an exact copy of AF9Y's at 11 turns. My first helix build. The second is an 18 turn also with the loop reflector but uses aluminum wire for the helix and the 10.66 in. loop reflector is 1/4 inch copper tubing.
I'm going to remove it soon and change to a screen reflector to try out Claire's (VE3NPC) matching system.
I'm working up an article on helix building and what I've been able to put together is that the reflector can be .6 to 1.1 wavelength.
The ARRL Satellite Experimenters Handbook specifies .6 wavelength in their chart.
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