[TowerTalk] 2 el yagi question

[Peter FORBES]

Tom,

That's a great "deep and meaningful" question.

Assuming the dipole Is currently matched to the feedline then at least two
things are going to happen:

(1)  Because of mutual coupling, the feedpoint impedance is going to lower
on the dipole

(2)  the addition of the director is going to change the vertical pattern of
the dipole, probably lowering it (but as one correspondent said) it will
depend to some extent on the initial height of the dipole.

So with reduced feedpoint impedance, you will need to rematch the feedline
to the dipole   and with changed vertical pattern it might well be that the
signal actually reduces if the vertical pattern changes such that it no
longer corresponds to the angle of arrival of the signal.

Great to see that you are still active Tom - I still remember all those qsos
on 160mx from the 60's and 70's.

Cheers

Peter   VK3QI




-----Original Message-----
From: towertalk-bounces at contesting.com
[mailto:towertalk-bounces at contesting.com] On Behalf Of Tom Osborne
Sent: Friday, 18 May 2012 9:43 AM
To: Towertalk
Subject: [TowerTalk] 2 el yagi question

OK, this may be a dumb question, but I've been wondering.

Say I put up a dipole going E and W, and there's an S-9 signal on the dipole
coming from the South.

If I put a director in front of the dipole, will the signal still be S-9 on
the dipole?

Just wonderin'.  73
Tom W7WHY



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