[Elecraft] 43 Ft Vertical and Elecraft Tuners

[Jim Brown]

YES!  You've hit the nail beautifully on the head, Ron. I just finished 
preparing slides comparing a 43 ft ground-mounted vertical with a good 
radial system on 20M, 15M, and 10M with a classic ground plane at 30 ft 
and vertical dipole with a base at 30 ft for those bands.Looking at 
performance below about 15 degrees elevation, the three antennas are 
roughly equal at the low angles on 20M, but both the ground planes and 
the vertical dipole blow the 43 ft vertical away on 15M and 10M (the 
difference ranges between 6-8 dB, depending on ground conductivity).

The practical problem with sticking a ground plane on your roof is that 
it needs at least two radials per band, but there are several multiband 
antennas for those bands configured as vertical dipoles that work well 
without radials. That's the basis of my earlier statement that a 
roof-mounted well-designed multi-band vertical dipole is a far better 
antenna above 20M than the 43 ft vertical.

73, Jim K9YC

On 9/3/2013 2:28 PM, Ron D'Eau Claire wrote:
> An interesting point I noticed modeling a 43 foot vertical was that, while
> on 10 meters the main lobe is up around 50 degrees, the "gain" at low angles
> is similar to a 1/4 wave "ground plane" antenna cut for 10 meters. That's
> because the longer antenna has significant gain over a 1/4 wave antenna so
> the amount of radiation down at the lower angles is about the same as a 1/4
> wave.
>
> That's for a ground mounted 1/4 wave on 10 meters. Ideally you want to raise
> the 10 meter vertical at least 1/2 wavelength - roughly 16 feet - then you
> get much better low angle radiation from the 1/4 wave because the ground
> absorbs much less of the lowest angle radiation. Installed that way, the 1/4
> wave shines over the 43 footer. Also, of course, there is less interference
> with the signal by foliage, buildings, etc.