[Elecraft] Carolina Windom Antenna?

Tue May 27 10:05:59 2003

Tom:
  First, there is no reason to spend $120 for something you can easily put 
together yourself.  Get yourself a couple of rolls of 14 or 12 gauge 
copperclad, 7 strand wire of appropriate length, a few insulators and some 
300 or 450 ohm open wire or ladder line.  Some people swear by 12 gauge, 
but my experience shows 14 to be perfectly adequate.  Open wire feed line 
is preferable, but if you can't find it, ladder line will do.  Now go to 
it.  If you can center feed the antenna, that is likely the best choice, 
regardless of its length.  Now the principle is simple: put up as long a 
flat top as you can as high as you can.  This antenna, particularly at 129 
feet, will require a transmatch, a tuner.  Balans can be made to work, but 
are really best avoided altogether.  You can homebrew any number of 
transmatches that take the unbalanced coax feed from the K2 into a truly 
balanced output, which you will want with the center fed antenna.  Grab 
some coil stock (you can still find B&W stock on the web) and some variable 
caps.  At 100 watts out, you don't need anything very special; indeed you 
can get by just fine using some good ol' broadcast receiver caps (365 pf 
per section or the like).

As to trees: merely passing by, or even through the crotch of a tree will 
have almost no practical effect.  Actual contact with branches can cause 
problems.  It will reduce the efficiency of the antenna, disrupt the 
pattern, cause instability in the tuning when the wind causes the branches 
to change contact with the wire, cause asymmetry in the current 
distribution in the two legs of the antenna, and could cause physical 
damage through rubbing.  However, it will work and will produce an antenna 
that is considerably better than no antenna at all.

If you do have radically different physical situations in the two legs of 
the antenna (because, perhaps, of tree limbs), the homemade transmatch has 
a great advantage over most commercial varieties in that you can tap the 
different sides of the output coil differently to compensate.  Such tuning 
will require significant experimentation on different bands, and is best 
done using some sort of antenna analyzer such as the MFJ 259B.  This is a 
very worthwhile investment.

best wishes,

dave belsley, w1euy

--On Tuesday, May 27, 2003 5:08 AM -0400 Tom Crites <[email protected]> 
wrote:

> I'm looking to replace my "wire-in-a-tree" antenna I use at my cottage
> with something a little more substantial.  I have about 129 feet to work
> with and was looking at a Carolina Windom "Short" 80 ($120) from The
> Radio Works (www.radioworks.com).  Can anyone comment on this antenna, or
> have a suggestion on a good 80-10 meter antenna.  I was also wondering
> how much of an impact it would have if the antenna did contact a few
> branches/leaves. My home QTH antenna is a G5RV, radio is a QRP K2 with
> tuner.
>
> Thanks,
> Tom, KC8SES
>
>
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----------------------------------
David A. Belsley
Professor of Economics