[TowerTalk] TA-33 feed

[w8ji.tom]

I sure liked my TA-33. It was my first store bought yagi, and I was amazed
how much DX I could work with it! Ahh, the good old days before 160 meters!


> Attach the coax directly to the driven element, and put the coax through
> about a dozen large ferrite beads to minimize feedline radiation. Be sure
> to ground the braid side of the element and coax to the boom as per the
> instructions. When I put up my first ta-33 years ago, I forgot to do

If one leg of the driven element is grounded, the electric field at the
feedpoint is disturbed and
what should ideally be a balanced element is forced to an unbalanced
condition. That causes the boom and tower to radiate along with the
antenna, and makes the balun almost totally
ineffective.

I tried my feedpoint with one side grounded, and found the F/S and F/B OK
but not great.

I then added a balun and grounded the shield on the *transmitter* side of
the balun. F/B and F/S
ratio improved noticeably. As a side benefit, power handling will also
increase
a bit (because each trap shares equal voltage and current, rather than one
trap getting the bulk of current and voltage in the elements).

By all means ground the coax, but on the transmitter side of the balun.

73 Tom


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