[Lowfer] FW: 600MRG> Helically wound vertical on a city lot>NO WAY!!!

[Ed Phillips]

WE0H wrote:
> 
> Here goes a good argument if anyone wants to take it on. This is all about
> some other guy wanting to build a helical wound vertical for 166.5kc. I told
> him that it wouldn't work and to use a typical 50' Lowfer vertical with some
> radials and a good coil/variometer. He didn't like my suggestion nor does
> this guy below. His address is john@mcaulay.net.
> 
> 73's,
> Mike>WE0H

	I've been involved in two attempts to use helical verticals in the
LOWFER band.  First was an antenna put up in Riverside, CA by Bill Gates
(N6WHP).  He is a very competent and careful builder, but the signal
from NR was barely readable at a range of about 70 miles, and the
antgenna would only work in very dry weather.  Same beacon on a 40 foot
vertical was good copy.  Conclusion: A bust and not worth the effort.

	Second was was a helical vertical at ELU (Randy Seaton, WD6ELU) in Simi
Valley, CA.  Randy wound this 40' vertical on 2" PVC pipe, and several
of us went out to help him erect it.  Real exciting day.  Helpers
included me, Bill Gates, Bill Lake (WB6RIJ), and Dave Curry (WD4PLI). 
It turns out that the out that that length of pipe was about as rigid as
spaghetti!  We had several ropes on it and fastened the base securely
and then tried to raise it.  Both ends clung to the ground but after a
lot of effort got it to try to stand up.  One of the problems was that
we who were holding the ropes kept collapsing in laughter at the
stupidity of the whole affair.  Eventually got it up and pretty straight
after a couple of hours of work and laughter.  Problem was that it
barely worked at all.  I could never hear it here about 30 miles away
and Dave could barely hear it in Burbank.  On his "old" antenna the
signal from ELU was pretty good here and Dave and Randy used to have
regular and very solid SSB QSO's on Saturday mornings.

	Both of these antennas were reasonably well built and "worked" against
good grounds.  Almost any edition of the ITT handbook "Reference Data
for Radio Engineers" has a section with good design data on helical
antennas of all sorts.  It states that the radiation resistance of a
resonant vertical helix above a perfect ground plane is
(25.3 x h/lambda)^2, while for a short monopole the factor 25.3 becomes
20.  Under the best of circumstances that's a lot of work to get a very
small improvement.  For a 50 foot height at 180 kc that works out to
0.054 ohms compared to 0.033 ohms for the monopole.  Top loading the
monopole (TV masts are sure cheap!) is clearly the way to go.

My opinions.  Have at it if you have the ambition, but please share the
results.

Ed
IZJ
W6IZJ