Chuck,
I just recently finished a round of antenna tuner thrashing that
included some vertical, half wave wire, bottom fed antennas... This
was through a tuner(s) of my own design and construction including
hand built variable caps, with the feed points being head high and
the 1/2 wave antenna worked against a half wave elevated counterpoise,
with the coax dropping straight to the ground and running on the
ground hundreds of feet to the shack...... The ground was wet with
half melted snow and rain during most of the test... I had to stand
in a flowing stream to make tuner adjustments - snow melt water will
get your attention when it runs over the top of your boots!

While I got the tuner design to work - which was the whole reason for
the exercise as opposed to being primarily an antenna test - I was not
impressed with the half wave, end fed, vertical antenna overall - 80,
40, and 20 meter antennas were tested...
They were distinctly more noisy than ground mounted quarter wave
antennas for the same bands... Often, deafeningly more noisy...
The recovered signal strengths we
1. often less than for the quarter waves -
2. sometimes comparable -
3. the strong signal exceptions being the times that the very low
arrival angles were exactly what the half wave vertical wanted to
see...
(you can never have too many antennas)

On 20 meters the separation between the two antennas was 500 feet,
and expanding to some 900 feet for 80 meters test antenna being the
half wave end fed, and the reference antenna being 1/4 wave ground
mounted... I feel that the distances were sufficient that mutual
coupling was minimized enough as to not skew the results - it
certainly was not eliminated, however...

The circulating tank current on a tuner used transform 50 ohms to an
end fed half wave is impressive - often melting the dielectrics used
for the variable caps...

denny

Denny wrote:


The circulating tank current on a tuner used transform 50 ohms to an
end fed half wave is impressive - often melting the dielectrics used
for the variable caps...


Thanks for the report, Denny. Some of
the T- and L- network tuners also pass
some hefty currents at high power.

It is difficult to find much enthusiasm
for the performance of half-wave
verticals from folks who have actually
tried them. Your experience sure
supports that.

73,

Chuck

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On Wed, 20 Jun 2007 09:20:15 -0400, Chuck
wrote:

It is difficult to find much enthusiasm
for the performance of half-wave
verticals from folks who have actually
tried them. Your experience sure
supports that.

Hi Chuck,

I can report a bright side. During one field day, years ago, one
fellow brought in a baloon and hoisted enough wire into the sky to
work it as a halfwave 160M vertical. He used an optical rangefinder
to measure the height. He had this Army surplus tuner that tuned it
up to his rig. The 160M contacts he made told him he was the
strongest signal on the band (working 100W). Perhaps it helped that
we were in a school ball field on the top of a hill. To further add
to the mix, I suggested he tie the tuner to the fence line and
backstop.

73's
Richard Clark, KB7QHC

To further add
to the mix, I suggested he tie the tuner to the fence line and
backstop.

73's
Richard Clark, KB7QHC

That was canny advice, Richard... The top rail of the fence and
backstop 'could' have been an NVIS antenna - which will get you
smokin' reports out to a few hundred miles...
I do this routinely for Field Day with a horizontal loop for 80 meters
being strung about 20 feet high over a low, wet, fertilized field next
to a river... The guys run QRP off a battery and are amazed how they
can break pile ups... I have never bothered to point out to them that
the vast majority of their contacts are within a 500 mile circle...
They are happy and I believe in ignorance being bliss...


denny / k8do

On Thu, 21 Jun 2007 04:34:14 -0700, Denny wrote:

To further add
to the mix, I suggested he tie the tuner to the fence line and
backstop.

73's
Richard Clark, KB7QHC

That was canny advice, Richard... The top rail of the fence and
backstop 'could' have been an NVIS antenna - which will get you
smokin' reports out to a few hundred miles...
I do this routinely for Field Day with a horizontal loop for 80 meters
being strung about 20 feet high over a low, wet, fertilized field next
to a river... The guys run QRP off a battery and are amazed how they
can break pile ups... I have never bothered to point out to them that
the vast majority of their contacts are within a 500 mile circle...
They are happy and I believe in ignorance being bliss...


denny / k8do

a local qrp contact is still a qrp contact. Many contacts is better
than few, if that's what you are wanting to make.

It might not win field day, but it has to be better than not being
heard atall.

--
73 for now
Buck, N4PGW

www.lumpuckeroo.com

"Small - broadband - efficient: pick any two."