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Helix around a Patch



I am still trying to come up with a nice Portable rig for FL. I have tried
my dual helix (2/Ghz) feed for my old 60cm dish and I am not satisfied with
the result on the S-Band Downlink.

Now, I am going to use a James Miller Patch on one of his solid 60cm alum.
dishes as the downlink. I wish to construct a Helix (2-3 Turn) around the
patch for a 1ghz uplink. I have the necessary filters and they work well.

Here is the question: Does anyone have experience winding a helix with
decreasing diameter. The problem is that the reflector on the patch is
larger than the approx. 3" diameter of the Helix winding. My thought was to
start out with a helix of say 6" in diameter until I was clear of the patch
reflector and then gradually, or not so gradually, scale down to the desired
3". It would only require about 1/3 of a turn (the thickness of the patch)
to get clear of the patch and start pulling in.

Any and all thoughts will be appreciated.

73
Gunther Meisse
W8GSM
AMSAT LM#594

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