Richard
My question was placed at 'two whips to form a dipole'.
It was not a recomendation nor did it call for comparisons
to other designs that may be better.
With that clear I stated that the max radiation will be at 90 degrees
and that I am sure is accepted and will provide local contacts.
Now placing the two whips on top of the tower negates the need for a
ground plane which is no small matter as well as half the max
radiationwill be at
45 degrees. Thus the simple question is anybody using two whips as a
dipole?
I could well imagine a setup of a loaded dipole being a very GOOD
antenna in some instances because of the avoidance of ground losses
with those having a small lot or do not have the facilities for
extensive ground planes.
My dipole is 50% efficient on 160, 90% on 80 which means in each case
for TOA
in the 40 to 50 range they exceed gains for a run of the mill
vertical.
So again Richard I asked for experiences from those using two loaded
verticals made into a dipole for horizontal polarisation on 160M.
Regards
Art







(Richard Harrison) wrote in message ...
Art, KB9MZ wrote:
"---it should provide good local contacts if placed at a height of 70
feet."

If back to back mobile antennas are used as a dipole at 70 feet, the
question is: why not use the vertical distance for a radiating
conductor, and the horizontal space to load the too-short vertical?

1/4-wave at 160-meters is about 131 feet.

A vertical mobile antenna is likely limited to about 4 meters and a
dipole made from two is only about 8 meters long. That`s only 10% of
1/2-wavelength. Radiation resistance of such a short dipole will be very
low and capacitive reactance will be very high requiring much reactance
to tune out. This is inherently lossy.

Another disadvantage if the dipole is only about 1/8-wavelength high and
horizontal, will be concentration of most radiation directly overhead.
For local and DX coverage, energy concentration near the horizon is
important. Vertical antennas provide low angle radiation even when they
are short. They have a null directly overhead.

70 feet is 53% of the height required for 1/4-wave resonance at 160
meters, and some of the missing length can be made up by horizontal
loading at the top of the vertical height.

ON4UN`s "Low Band DXing" Chapter 9, "Vertical Antennas" can be very
helpful in choosing a configuration that will work well.

Best regards, Richard Harrison, KB5WZI

Art, KB9MZ wrote:
"It was not a recommendation nor did it call for comparisons to other
designs that may be better."

Art is correct. Vertical antennas require radials to avoid ground loss.
Norizontal dipole radiation in free-space is perpendicular to the
antenna.

Art also asks: Is anybody using two whips as a dipole?

I`m sure they are. Saw a hamfest vendor selling loaded whips and mounts
designed to mount two of them as a dipole. There have been discussions
in previous threads about this application. Hope there are new responses
to Art`s question.

Best regards, Richard Harrison, KB5WZI

On 4 Dec 2003 08:42:58 -0800, (Art Unwin KB9MZ)
wrote:

I asked for experiences from those using two loaded
verticals made into a dipole for horizontal polarisation on 160M.
Regards
Art

Hi Art,

Miserable. A simple balloon lifted halfwave vertical was declared the
big guns by a net (surpassing their own antennas).

Richard was right, more signal would find its way out if you simply
drove the coax shield running up to the "dipole."

73's
Richard Clark, KB7QHC

Exactly
The ground influence on verticals is horible so getting
away from it or going horizontal are good viable choices
depending on the TOA required for your own particular purposes
Art


Richard Clark wrote in message . ..
On 4 Dec 2003 08:42:58 -0800, (Art Unwin KB9MZ)
wrote:

I asked for experiences from those using two loaded
verticals made into a dipole for horizontal polarisation on 160M.
Regards
Art

Hi Art,

Miserable. A simple balloon lifted halfwave vertical was declared the
big guns by a net (surpassing their own antennas).

Richard was right, more signal would find its way out if you simply
drove the coax shield running up to the "dipole."

73's
Richard Clark, KB7QHC

On 5 Dec 2003 06:08:46 -0800, (Art Unwin KB9MZ)
wrote:

Exactly
The ground influence on verticals is horible so getting
away from it or going horizontal are good viable choices
depending on the TOA required for your own particular purposes
Art

Hi Art,

You really need to read posts before "agreeing" with them.

73's
Richard Clark, KB7QHC


Richard Clark wrote in message . ..
On 4 Dec 2003 08:42:58 -0800, (Art Unwin KB9MZ)
wrote:

I asked for experiences from those using two loaded
verticals made into a dipole for horizontal polarisation on 160M.
Regards
Art

Hi Art,

Miserable. A simple balloon lifted halfwave vertical was declared the
big guns by a net (surpassing their own antennas).

Richard was right, more signal would find its way out if you simply
drove the coax shield running up to the "dipole."

73's
Richard Clark, KB7QHC