Since a lot of people asked me to share information on TH6DXX beta match
measurements I decided to post it to reflector.
I think N0AV, N6BM and W9JCC don't mind. Again big thanks to them for the
help.
N0AV:
> >I have three TH6's up on a 100' rotating tower. I climbed to the bottom
> >antenna and measured 2.75 inches between the end of the beta tubes and
the
> >center of the driven element. The beta tube insulator position is
probably
> >not too critical...it looks like my top one is about the same as the
bottom
> >one but the middle antenna has the insulator out a little further. On the
> >bottom TH6 the edge of the insulator is 6.5 inches from the center of the
> >driven element.
> >
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**
N6BM:
Just took the measurement you wanted. The distance from the
center of the DE to the center of the first beta insulator is 7 3/16
inches. Hope this helps. Let me know if you need any more info.
****************************************************************************
****
W9JCC:
Yuri,
The distance to the beta support is not critical. My recollection is that
the two supports are placed about 6 to 8 inches from each end of the
large beta tubes. Refer to Figure 8 of the Manual. I would estimate it
from the detailed picture in the manual. It is for mechanical integrity
only. I have a TH6DXX in the garage attic, that has the Beta Match still
attached. The outside temp here is about 95 deg F and it must be over 50
deg C where the antenna is. So I'm not going there now. If you have the
major pieces of the Beta Match (The two long tubes and the "U" shapped
aluminum wire), it should be very easy to reconstruct. There should be a
small hole in the boom where the aluminum wire was clamped to the boom
with a sheet metal screw and clamp. That locates the far end of the beta
match. The two ends of the aluminum wire portion connect to the two large
tubes. The open ends of the two large tubes should end up at about the
distance of the driven element. ie (The wires connecting the Beta Match
to the driven element should each be ~ 4 inches long.)
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