Re: Radials for Verticals

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From: David Gauding (david.gauding@bbs.galilei.com)
Date: Thu Feb 21 2002 - 18:31:03 CST


Good morning,

Jim Duffey is absolutely right! Vertical antenna and radial topics on QRP-L
are guaranteed to produce additional postings! Guess I want to jump in here
too, albeit a day or two late!

I keep Dr. Megacycle's comprehensive reply to my early 8th-wave radial
questions on file and refer to it regularly. Well-researched information is
held in high esteem here. I do appreciate such authoritative and justified
responses from Jim.

I started investigating 8th-wave radial options about eight years ago. My
intention was to reduce single wires to lengths more conducive to
short-term portable operations - at picnic tables and trailside locations -
without significantly degrading performance. The long-term outcome of that
experiment was the St. Louis Radials (ribbon radials) project.

To explain, I prefer to spend my time actually on the air when portable.
That does not include installing, optimizing or otherwise tweaking simple
single-element antennas in less than optimum locations. I was a
cliffdweller until 1998 (for 18 years) so having an antenna out in the sun
for a few hours then was always a special occasion. It's a hard habit to break.

Logistics and time commitments can get out of hand in attempts to
gild-the-lilly for that last fraction of a db. For what? A couple of hours
out in the boonies when most any contact is welcome? Bottom line: Do you
wanna' play with the radio or play with the antenna - out there?

Consequently, the portable verticals that I use in the field these days
(St. Louis Express or St. Louis Quickie) install in five minutes or less.
This desirable capability is provided collectively by a single ribbon cable
radiator, easily extended or assembled fiberglass support, a dual-purpose
feedpoint disk, and especially those downsized 8th-wave ribbon radials.

In the interest of speed and convenience, I abandoned all single-wire
radials for portable QRP, even in small numbers. Ribbon radials are so much
easier to install, retrieve and store thanks to their physical
configuration. The extra metal positioned under a vertical where it can do
some good is merely a bonus.

The SLX which tunes 10-40M uses nine 16.5' ribbon radials. The SLQ tunes
10-20M and uses eight 8.5' ribbon radials. I chose these quantities because
(1) the antennas work just fine with them for what I have in mind and (2)
they roll-up for storage in sets of three and four respectively and finally
(3) fit neatly in a single round rubber kitchen container. Real scientific, eh?

I operate with exactly the same portable vertical antennas and ribbon
radial sets at home as taken to the field. This procedure allows antenna
performance to be assessed as (1) an intact operating unit, (2) in the same
location and (3) over many months. Different operating hours and changing
propagation are then involved and the only obvious variable in our yard is
foliage. In my experience, sporadic portable sessions are essentially a
snapshot and do not provide enough information for subjective evaluation.

Prior to discovering the possibilities offered by computer cable, I
experimented for several years with both quarter-wave radials and folded
radials fabricated from twinlead. The latter were used under the original
St. Louis Vertical. Those radial experiments where also convenience
exercises in efforts to identify a compressed but effective radial
configuration.

Operating preferences here are for ragchewing, milliwatting, dxing and fox
hunting, in that order. Vertical antennas with ribbon radials are usually
the vehicle for doing that. How do 4th-wave radials compare to 8th-wave
radials for each of my preferences? I just don't know and don't plan to
expend the time and effort to find out. I'd rather be on the air!

I'm not saying 8th-wave radials are the answer to every operating situation
but they do work for me while helping make logistics much more manageable
in the field. That's my experience with and justification for choosing the
them.

Regards,

de Dave, NF0R nf0r@slacc.com


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