[Antennas] Carolina Windham

[Greg Troxel]

"Steve H" <teknoskillz at comcast.net> writes:

[resending as the list seems to have perhaps rejected this due to it being signed]

> I have a 80m Carolina windham up for some time now. Its got I think
> about 20-25 feed of 300 ohm ladder line from its feed point, and it
> connects to a 300W 4:1 balun and the other side of the balun is a
> 50 ohm S0-239 connector where I have coax eventually finding its way
> to the rigg.

I have a CW80 from Radio Works (which is no longer in business).  As I
understand it, there is a 4:1 balun with the short/long legs attached to
it, and then 22' of coax down to what is basically a choke (all
supplied), and then a regular coax feed (not supplied).  I can see it
and it's definitely coax not 300ohm line; the PL259 shape under
coax-seal is quite clear.

The claimed concept is that the 22' vertical section radiates and fills
in the pattern at low angles and various azimuths.  (Of course, this
also means that any notion of not picking up vertically-polarized noise
from horizontal dipoles no longer applies, but OCFD are pretty widely
criticized for picking up noise from the feedline.)

I am unclear on the type of balun; I'm guessing it is intended to have
some common-mode current on the 22' vertical coax.  But OCFDs may all be
like this and the unusual thing may be a choke after a while.  In my
case, I have another choke just inside the house.

So what you have seems quite different from what I have.


If you did have a Radio Works CW80 and want to build a 1500W equivalent,
then as I see it you might as well just make a new antenna.
However, you also might think about a different ratio as many of the
OCFD designs are more like 80/20 rather than 67/33.


If you are building you might want to look at this:
  https://hamwaves.com/cl-ocfd/en/index.html

Two people from my club re-discovered this; see
  Antennas,Multiband Off-Center-Fed Dipoles for 160 & 80 Meters, Rose (KC1DSQ) andGlorioso (W1IS), CQ 2020,Jun, p. 42


73 de n1dam