[TowerTalk] New Discussion: Dipole Secrets Part II

Ward Silver hwardsil@WOLFENET.com
Tue, 28 Apr 1998 07:39:36 -0700 (PDT)

> What is the collective experience with a lower dipole?  Has anyone modeled
> an dipole at 60 feet or less with trees, powerlines, guys, swingsets, chain
> link fences and all?
> k0wa@southwind.net

Assuming we're talking 80-m here, I wouldn't bother with the low dipole
except for regional coverage where a high radiation angle is a Good Thing.
Low, horizontal wires aren't going to put much energy below 30 degrees of
vertical angle.

If limited to a single support such as a tower with a tribander on it, the
half-sloper can often be made to work very well.  I have two pointed in
opposite directions, fed with coax and a remote antenna switch.  I am
apparently lucky in my choice of feedline lengths because I see a
significant f/b ratio, depending on arrival angle.  The antennas play
great - QRP from 7-land to V5 for example - and were easily tuned with the
help of an MFJ-259 and two thirteen-year-old rope holders.

If you have a tree to play with, you might consider a quarter-wave
wire vertical with a couple of elevated radials.  If you have two trees, a
bobtail or half-bobtail will work quite well.  One can bend the ends of
the vertical elements of the bobtail-type arrays if the vertical height
isn't a full 1/4-wave.  Preserve symmetry and it will work fine.

Also, the HF2V's will do pretty well if you give them appropriate ground
planes and pay attention to the details when putting them together.

This kinda got off the topic of dipoles, but some of us are pretty
dangerous with a keyboard...

73, Ward N0AX

FAQ on WWW:               http://www.contesting.com/towertalkfaq.html
Submissions:              towertalk@contesting.com
Administrative requests:  towertalk-REQUEST@contesting.com
Problems:                 owner-towertalk@contesting.com
Search:                   http://www.contesting.com/km9p/search