[Elecraft] 43 Ft Vertical and Elecraft Tuners

[Jim Brown]

On 9/2/2013 11:18 PM, Matt Moller wrote:
> I don't have any experience with 43 ft verticals myself but have heard 
> a lot about them and have been thinking about building one. I too 
> would like to learn more.

The reason for my post asking for experience with this antenna and the 
Elecraft tuner is that I'm putting together a presentation on 43-ft 
verticals for Pacificon next month. So far, I've done a lot of modeling 
to understand how a 43-ft vertical behaves on all ham bands, both when 
ground-mounted and on the roof of a typical home (with two radials for 
each band 40-10M).

A few years ago, AD5X did some excellent work on matching a 43-ft 
vertical, with engineering that can best be described as heroic, and 
shared it in an fine Power Point that he's done for ham clubs, and that 
is on the internet. He's given me permission to include parts of it in 
my Pacificon talk. That talk is scheduled for Saturday morning.

The day before, as part of the Antenna Forum, I'm showing a rather 
extensive study with the title, "If I Could Put My Multi-Band HF 
Vertical On My Roof, Should I?" Except for the 43-ft vertical, nearly 
all commercial multi-band verticals are resonant on the bands they 
cover, and are either monopoles with radials (a classic ground plane), 
or vertical dipoles without radials.  Various designs use anything from 
traps to a combination of traps, stubs, and matching sections to 
resonate the antenna and present a  50 ohm load. .

Both Power Points will be on my website after Pacificon.

As to radials -- some of the best work I've seen is by Rudy Severns, 
N6LF, who has done both extensive modeling and significant experimental 
work to confirm the models. His work is quite thoughtful, and presented 
in a manner that is quite readable (but not light reading). As to 
assigning resistance values to a given number and length of radials -- 
I've seen several published studies, some in the ARRL Handbook and 
Antenna Book, that come up with quite conflicting numbers. I suspect 
that the primary cause of the conflicting results is the nature of the 
soil underneath the radial system.  At Pacificon last year I did a talk 
about getting on 160M from a residential lot, which is mostly about 
antennas, radial systems, and counterpoises. In it, I collected much of 
the better work I've seen about radial systems.  The Power Point is on 
my website. http://k9yc.com/publish.htm

Based on my modeling, and upon an excellent set of measurements by N0AX 
and K7LXC of a dozen commercial verticals, if I had limited space and 
could not rig horizontal dipoles for the bands I wanted to work, I would 
use one of those commercial multi-band antennas configured as a vertical 
dipole, and I would put it on my roof.

73, Jim K9YC