At 16.20 16/01/98 -0800, you wrote:
>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 )
Tom,
I forgot to say in last message that C3XL was also tested without reflector
(when it was dismanted) and SWR went down. It seemed that the burnt
insulator pulled up the SWR. By the way, if you can assure me that the
performances of my beam will not degradate, surely I'll try to ground to
the boom. See you later and thanks again.
ps. Last May I asked you a free brochure of your production, but still now
nothing has arrived here. I am interested in vertical to put in a 4 square
array, possibly free standing, with no guys.
Thank you again
Sante
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