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.

With the DX Engineering balun in place as in the figure, no xmit and no
rcv ... i.e., no diff than open-ended (shorted?) coax.

When I bypassed the balun and connected the balanced twin lead directly
to the coax...NOW I have good receive and pretty good sig reports.

Yes a 6:1 balun should also work according to what I've read.

The feedline radiation is intended for the 300 ohm twinlead only, not
the coax below the balun.

I am pretty sure the balun is the Ruthroff type that Owen mentions
(i.e., not a CHOKE balun)

I guess I'll conclude that the balun has failed. However, on inspection
the balun looks perfect...it is only 2 yrs old, has5 KW continuous power
rating and I run 40 W. Also, it worked perfectly well when used
originally with the DX Engineering folded dipole, also using a 300 ohm
feedline. (this is why I chose the CW...I had the stuff for it)

I appreciate the discussion

John
AB8O

jawod wrote in :

I've attached the original article that describes the CW in question.

As you now know, that didn't work.

You need to put the article on a web site somewhere, or give the URL of an
existing copy.

Owen

Owen Duffy wrote:
jawod wrote in :


I've attached the original article that describes the CW in question.


As you now know, that didn't work.

You need to put the article on a web site somewhere, or give the URL of an
existing copy.

Owen
Thank you SO much Owen

here ya go

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

John
AB8O

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

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.


Thanks for the input. The strange thing is that the system failed at
ALL freq's. The original use of the balun was with a folded dipole and
a feedline of 300 ohm twinlead cut to an odd multiple of the lowest freq
desired...which I did and it worked reasonably well. I cannot
understand how this application (the CW OCF) is significantly different
from the original one, at least in terms of using a 4:1 balun.

Allow me to put this to rest. I can live with it as it is, theoretical
considerations notwithstanding. I don't want to go over to the dark
side, but, hey, it works. Maybe I have a new "Magic" Antenna.

John
AB8O

jawod wrote in :
... Maybe I have a new "Magic" Antenna.

Instead of the "perfect antenna" as claimed in the article!

Owen

When trying to understand off center fed antennas, it's important to
realize a few key facts:

1. A properly working "voltage" or "Ruthroff" balun will force common
mode current to exist on the feedline in its attempt to cause equal
voltages on the unequal length sides relative to the feedline shield.
2. Even if an effective "current" or "Guanella" balun is used, feedline
current will still be induced by the uneven coupling between the two
antenna sides.
3. A transforming balun is very unlikely to effect the expected
transformation ratio, and is likely to add a significant amount of
series and/or shunt reactance except at those spot frequencies where the
match is close to perfect.

This isn't to say that off center fed antennas can't sometimes be made
to "work", i.e., provide a reasonable impedance match on some bands. But
when they do, it's not for the reasons you think from an analysis
assuming a perfect transformer and balun. It usually involves a complex
relationship among the particular imperfections of the
balun/transformer, feedline, and path to the Earth taken by the feedline
shield.

Roy Lewallen, W7EL

Roy Lewallen wrote in
treetonline:

When trying to understand off center fed antennas, it's important to
realize a few key facts:
....

Yes, I thing you are quite correct Roy.

The advertising hype that goes along with many of these commercially
popularised antennas gives the impression that deployment of multi-band
wire antennas for the lower HF bands is a very standardised thing, a no-
brainer. One buys the product, installs it in their own environment in
their own way, and it just "works" out of the box... whatever "works"
means.

The real world doesn't work that simply.

But to a buyer with faith in the promotional claims, they can buy a lot
of satisfaction for only $69.99 or whatever, and not have any untidy left
over materials to clutter up their home, or residual technical issues to
clutter up their mind.

Today, the growth opportunity in the US is selling attic antennas for low
HF bands to new hams. Not as popular here because restrictive covenants
on residential properties aren't as common.

But, hey, a simple wire antenna with published performance figures from
160m to 2m is attractive to *our* new six hour hams. Which antenna is
that? The W5GI Mystery Antenna, you know, the one "that performs
exceptionally well even though it confounds antenna modeling software".

Owen

Owen Duffy wrote:
Roy Lewallen wrote in
treetonline:

When trying to understand off center fed antennas, it's important to
realize a few key facts:
...

Yes, I thing you are quite correct Roy.

The advertising hype that goes along with many of these commercially
popularised antennas gives the impression that deployment of multi-band
wire antennas for the lower HF bands is a very standardised thing, a no-
brainer. One buys the product, installs it in their own environment in
their own way, and it just "works" out of the box... whatever "works"
means.

The real world doesn't work that simply.

But to a buyer with faith in the promotional claims, they can buy a lot
of satisfaction for only $69.99 or whatever, and not have any untidy left
over materials to clutter up their home, or residual technical issues to
clutter up their mind.

Today, the growth opportunity in the US is selling attic antennas for low
HF bands to new hams. Not as popular here because restrictive covenants
on residential properties aren't as common.

But, hey, a simple wire antenna with published performance figures from
160m to 2m is attractive to *our* new six hour hams. Which antenna is
that? The W5GI Mystery Antenna, you know, the one "that performs
exceptionally well even though it confounds antenna modeling software".

With all respect, Owen - a Ham can be just as ignorant if they tested
in the days when we had to mine and smelt our own copper for antennas.

There is plenty of ignorance to go around.

Before I go too much further, Hams should build their own wire
antennas. No excuses.

The interesting thing is that most of these novel antennas work to some
extent. I know a fellow in PA who was excited that he could work Maine
on 40 meters with a really bad antenna setup. He just didn't know what
to expect. (from where I'm at, 100 watts and a modest dipole should just
about ruin an S-meter between those two places)

That is how antenna BS starts. This guy would think that a poor antenna
is great because it performs better than his awful antenna.. 8^)

I won't come out and condemn things like OCF dipoles though, because
they are an interesting and cool novelty, and by gosh, I had fun
building, testing, and using mine. I learned a lot. Used one during
Field day, and ran and held frequencies at 100 watts on 80 meters.
Totally subjective of course, but low power stations usually don't do that.

One of the things I learned was that it is a real compromise. Higher
band performance wasn't so hot. But I'm a lot better off having built
it, and finding out it's capabilities and shortcomings, than just
believing that it is a bad antenna because I've been told it was so. I
know exactly what the antenna is like, and it only took me a few hours
of work, and a couple months of testing to find out.

I note this mainly because I am one of the unwashed new Hams - and we
aren't all as you describe.

- 73 de Mike N3LI -