should the beta tubes running on top of the boom
be level and straight all the way across the boom, or does it take a
bit of a bend when going past the balun point and the
boom to mast mounting plate??? I don't see a good enough picture of
this in the TH7 assembly manual.
An older (February 1983) "Telex" version of the manual in my file shows
the beta tubes offset (rotated) slightly away from the mast as they pass
the boom to mast bracket. The caption for Figure 10, page 11 says "3/4"
gap between edge of tube and top of bracket." The same information is
contained in Figure 9 of the "MFJ" version of the TH7DXX manual.
As a practical matter, one would install the tubes *straight/parallel*
(except for the crossover straps at the rear of the boom to mast
bracket) past the boom to mast bracket which would have them rotated
slightly away from the mast *the entire length of the beta match*.
After the tubes, beta feed jumpers (58) and crossover straps (57) are
installed, the balun (BN-86) is mounted. If the original rigid feed
straps (59) are used to connect the balun to the beta tubes at the front
driven element, the balun will not be directly at the bottom of the boom
but rotated slightly to the mast side of the boom. The flexible wires
used to connect the beta tubes to the driven elements will accommodate
the rotation of beta tubes relative to the elements.
73,
... Joe, W4TV
-------- Original message --------
From: Ted Boerkamp
Date:09/15/2017 6:07 PM (GMT-06:00)
To: "Towertalk Reflector (E-mail) (Towertalk Reflector (E-mail))"
Subject: [TowerTalk] TH7DX question
Hello...can someone tell me......if you build the TH7 beam properly, should
the beta tubes running on top of the boom
be level and straight all the way across the boom, or does it take a bit of
a bend when going past the balun point and the
boom to mast mounting plate??? I don't see a good enough picture of this in
the TH7 assembly manual.
Hoping someone might remember how they built theirs.
Thanks
Ted VE3SS
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