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Old October 29th 08, 06:25 AM posted to rec.radio.amateur.antenna
John Smith John Smith is offline
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First recorded activity by RadioBanter: Nov 2006
Posts: 2,915
Default Carolina Windom without a balun: go figure

jawod wrote:
Well, as an update to my Carolina Windom project, I find that the CW OCF
dipole cut to typical dimensions works well WITHOUT a balun but does not
work at all WITH a balun.

Specifically, a DX Engineering BAL200-H10-AT 4:1 balun. I bought it to
go with a folded dipole from DX Engineering. It worked fine with the
folded dipole and a length 300 Ohm ladder line as feed.

When I use the above balun with the CW cut to typical dimensions and
using a 300 ohm ladderline feed, even RECEIVE is muted...no change from
coax only.

I am fairly sure that the balun is a voltage type and not a choke type.
I also installed a series of ferrite beads from Palomar to choke the
coax near the bottom of the ladderline.

I guess I'm not all that surprised that the CW works without a
balun...the ATU tunes it and sig reports aren't bad. I guess I have
some radiation from coax and a mismatch from coax to ladderline but I
think I can live with that. It's getting cold and I needed to finish
this thing before winter really sets in.

I am clueless as to why the CW failed to work AT ALL when USING a balun.
The internals of the balun look fine.

Any thoughts?

(here goes)

John
AB8O



Hmmm ...

Cecil is the first one to even get me to try an OCF antenna! I thought
I like my life "balanced"; now, I find, I can go though life
"unbalanced" and "off center." grin

However, the 300 ohm line you are using IS balanced. So, I am assuming
you have a 50 ohm UNBALNCED output from your rig OR PA, and this is
where you would insert the 4:1 (6:1 would be better), and that you have
inserted it there, right? Properly, directly at the rigs output, to
engage the 300 ohm line, right? (i.e., between the rigs 50 ohm
UNBALANCED out and the 300 ohm balanced line?)

If you have it there, and did not notice an improvement, or at least no
change, we have another problem--apparently ...

Warm regards,
JS