To answer Jim's question, Yes, you can run the feed line on the, what you
refer to as the HOT boom. But, unfortunately, it must be bonded to it.
With an Aluminum boom, placing the coaxial silver plated braid, or solid Cu
shield, makes for a difficult electrical "Bond".
You could use RG-141 or UT-141 inside the boom as an alternate method,
bringing it out at the feed point forming an "Infinite Balun".
Tom W3FRG
Continuing the discussion on how to attach the coax to the “hot” boom of a
Tennadyne T8 antenna.
As I assembled this antenna, I became increasingly confused and concerned
about the feed system. With this log antenna, instead of running open
feedline wires crossing over to the elements, it uses two boom pieces and
each is insulated from the mast and each boom is “hot”. The instructions
indicate and show how to attach the feedline to the bottom boom piece using
a Collins type balun at the feed point which is at the forward end of the
antenna.
My concern is that of the coax shield separated only by the coax insulation
alongside one of the “hot” boom pieces would couple and cause radiation
(phase shift) problems with the antenna or at the very least radiate as it
goes vertical down the mast.
Due to the element mounting method it is not possible to run the feedline
inside the boom to the mast.
Does anyone have any thoughts on why running the coax along the “hot” boom
would be an OK idea?
And if not, how else would one feed the antenna?
Jim – KR9U
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