On Wed, 29 Oct 2008, jawod wrote:

here ya go

www.w5fc.org/files/QRP%20Expressions.pdf

John
AB8O


This was the article that convinced me to build a NCW. (The 3rd option)
I scaled mine up to the 132 ft version so I could have 80m.

When I finally have a QTH to support its size, I will string it up
permanently. Till then, it is my field-day antenna of choice.

My 706IIg with AT180 autotuner have no trouble getting a clean match on 6m
thru 80m.

jawod wrote in :

....
Thank you SO much Owen

here ya go

www.w5fc.org/files/QRP%20Expressions.pdf

There are a host of issues with the content of the article. I don't
intend to red pen the article, but the issues sound a warning about
credibility.

There is no doubt it describes a Ruthroff 4:1 balun in its "new Carolina
Windom" configuration. Such a balun will have a very low common mode
impedance.

Factors of your implementation that are / may be different include:

The DXE balun you used appears to be described as a current balun on the
DXE web site. If it is, it may work differently. (I have already
commented on the lack of clarity of the product information, perhaps they
might clarify it if you email them with a support question - "what did I
buy?".)

DXE also warn us that 'tuner' style baluns such as the one you used are
more likely to be reactive an higher frequencies... presumably a
consequence of thicker wire insulation which increases the Zo of the TL
sections which results in less ideal impedance transformation with
increasing frequency.

Owen

jawod wrote:
Three versions of the Carolina Windom are presented:
Original single wire feed,

Actually, not a Carolina Windom - simply a traditional
Windom, the grandfather of all Windoms - named after
Major General Loren G. Windom, W8GZ, (Windy) (QST,
Sep 1929, pp 19-22, 84).

www.geocities.com/w8jyz/8GZ.pdf

OCF with twinlead and balun,

Don't know if it was ever a commercially available
antenna called a "Carolina Windom" but this is just a
traditional "Off-Center-Fed Dipole" labeled as such in
my 1957 ARRL Handbook.

http://www.w8ji.com/windom_off_center_fed.htm

and OCF with 10' length of coax

This is what most people think about when someone says
"Carolina Windom" and the reason that some people were
confused.

http://www.hamuniverse.com/k4iwlnewwindom.html

I guess I'll conclude that the balun has failed.

At least hang a 200 ohm non-inductive resistor on the
output and measure the input impedance. I don't know
how you can assume the balun has failed if you don't
know what impedances the balun was having to deal with.
--
73, Cecil http://www.w5dxp.com

On 2008-10-29, jawod wrote:
I've attached the original article that describes the CW in question.
Three versions of the Carolina Windom are presented: Original single
wire feed, OCF with twinlead and balun, and OCF with 10' length of coax
to a choke balun (1:1). Mine is the middle one. Please see Fig 3A. The
balun is at the bottom of the twin lead (I think I mistakenly referred
to it as ladder line). I added large ferrite beads just below the balun
on the coax as discussed here in the group earlier.

If I'm reading this correctly, you put the balun at the bottom of the twin
lead and the ferrite bead balun just under it.

Many 'Carolina Windoms' use the balun at the feed point, the ladder line or
twin lead under that, and the ferrite bead balun at the bottom of the ladder
line, to which is attached the coax.

Placing the balun (4:1 or whatever) under the twin lead would really do
strange things to the impedance and probably cause the problems you mentioned.

73 ...Edwin, KD5ZLB
--
__________________________________________________ __________
"Once you have flown, you will walk the earth with your eyes
turned skyward, for there you have been, there you long to
return."-da Vinci http://bellsouthpwp2.net/e/d/edwinljohnson

Edwin Johnson wrote:

...
Placing the balun (4:1 or whatever) under the twin lead would really do
strange things to the impedance and probably cause the problems you mentioned.

73 ...Edwin, KD5ZLB

Actually, I would expect placing a 4:1 balun under the 300 ohm balanced
line and before the 50 ohm unbalanced to provide a step-up(or step-down,
depending on the "direction" you view it from) of 50:200 or 4:1, as it
properly should. However, as someone presented in a paper a little
while back, some antennas "filled with errors" are able to function in
some manner and end up gaining their supporters ...

If you were to place a 1:1 balun at this same point, I would expect
little difference, but a difference (and, since you are mismatched at
this point, simply maintaining this mismatch with a component
introducing some loss and "redirecting" CM currents, not a good difference!)

It seems the "misunderstood/mystical/magical balun" lives on ...

Regards,
JS

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.


Hey John,

Trying to make sure that we are on the same page here.

You are using a OCF dipole with a 4:1 Balun, and using ladder line to go
from the balun to the shack?

Most of the OCF's I am familiar with run coax from the balun to the shack.

What are the respective leg lengths here? Height? Something is a little
askew here.

- 73 de Mike N3LI -