Hi Greg,
I'm unfamiliar with this particular antenna. But in general when
making adjustments to a store bought Yagi, set the parasitic
element dimensions to manufacturer's recommendations. Beyond
verifying the proper operation of any traps which may be in
parasitic elements, leave them alone.
Does this beam have a single trapped driven element? Or is it
one of the multi driven element or sleve designs?
If it has a single trapped driven element, first verify that all
the traps are functional. Then start with the ten meter
(innermost) part of the element to get things where you want them
on ten. Fifteen is next, then 20 (element tip lengths).
Depending on how the traps are constructed, 15 may not be
particularly adjustable.
Good luck.
73, Eric N7CL
>From: "Greg Gobleman" <k9zm@frontiernet.net>
To: <towertalk@contesting.com>
>Date: Wed, 8 Sep 1999 18:30:18 -0500
>
>Hi Folks,
>
>Please put on ur thinking caps. I have the TB6EM down for
>annual repair, adjustments etc. The useable portion on 15m has
>been a bit high in the band. 10m has been a real pain. I have
>a minor dip to 1.5 : 1 at about 29.500. I found the main dip at
>27.680, just right for the outlaws but it sucks when trying to
>work Mount Athos. I tried adjusting the fed element but only
>really made a difference on 15m. So I set 15m for the best, 20m
>is fine. I had the idea that maybe I could shift the passband
>on 10m if I make an adjustment to either the 1st director or the
>reflector both of which are 10m only elements. It was my
>intention to leave the 2nd director alone as I did not wish to
>effect F/B or anything else on 15 or 20m.
>
>Ideas anyone? I could sure use a bit of help on this one. Yeah
>I know, I could put up another antenna for 10m. What's the SWR
>on 10? 1.5:1 at 28.000 climbing to 3:1 and then a minor dip to
>2:1 at 29.500.
>
>Thanks es 73
>Greg K9ZM
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