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Old December 24th 10, 03:16 PM posted to rec.radio.amateur.antenna
Baron[_2_] Baron[_2_] is offline
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First recorded activity by RadioBanter: Jun 2009
Posts: 37
Default Balun for a yagi

Hi Ralph,
Ralph Mowery Inscribed thus:


"Baron" wrote in message
I've tended to prefer a gamma match... its far more flexible in
terms of matching and does the balanced to unbalanced conversion as
well.


The gamma match does not seem to be thought of as working very well at
vhf and above.


I've never had any real problems even at 23cms. Certainly non even with
other feed techniques that I've tried.

Also it defeats some of the purpose of a balun on a beam.


I agree that it wont necessarily prevent common mode currents on the
co-ax.

The balun is to keep the current in the antenna balanced which the
gamma match will not to. This tends to skew the pattern of the
antenna if the current is not balanced on the antenna elements.


I've not really noticed any problems with pattern skew, though I have no
doubt that it occurs. I suspect that it would be more of a issue with
phased arrays.


OT. Merry Christmas to all. (*)

--
Best Regards:
Baron.