Good afternoon.
Appreciate all the information.
This situation still is unique. This means I have no knowledge of this
happening...on anybody's antenna. So, let's continue to see what this can
be.
As mentioned, the reflector can be grounded, or not grounded to the mounting
(boom). It makes no difference. So, having a situation with high VSWR
because of something at the center of the reflector is very strange.
Best suggestion is:
Remove the insulator and clamp the element directly to the mounting.
The model for this antenna shows the following:
A) standard, with all elements, feed point on 20 mtrs is:
29 ohms -j10 (1.84:1 before matching)
B) with 20 mtr reflector removed, feed point is:
41 ohms -j22 (1.7:1 before matching)
The hairpin match will step up the feedpoint. It does not look like it could
move it up to 3:1 even with the reflector removed.
Please let us know the result of grounding the reflector. It should be like
it was originally.
Have a good day and 73,
Tom, N6BT
Force 12 Antennas and Systems
(Home Page http://www.QTH.com/force12 )
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