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Dave Heil[_2_] · November 11th 07, 10:47 PM posted to rec.radio.amateur.antenna

wrote:
Greetings!

I would like to build a 2 element inverted VEE yagi antenna. I
have seen this type of antenna in a SWL publication.

I would like the Yagi to be used on 7 mhz

I am seeking opinions as to the performance of such an antenna

The driven element will be a 7 Mhz half wave dipole ( 66 feet total)

The reflector element will be about 5 % longer

The spacing of the reflector will be about .20 wave length. about 26
feet from the driven element.

The angle of the vee will be about 55 degrees .

The feed line will be open wire 200 Ohm feed line to a true balanced
tuner.... no baluns truly isolated tuning network just like the
1940's you know, the tank coil type with an adjustable link in the
center of the tank then up to the driven element.

I know that the driven element impeadance will be low so I will use
3/8 inch aluminum power line (ACSR cable) for all of the feed lines
and elements.

The terrain under the antenna system is a 'cow' Pond that has water
in in most of the time, the terrain is low and is alway wet.

Please provide your thoughts on this antenna

Dave, You might want to consider an alternative: an inverted vee phased
array with .125 wave spacing, having equal lengths of coaxial cable to
the shack. You can build a small enclosure with a switch and enough
coaxial cable to produce 135 degree phase shift. The switch can be set
up to reverse the array and a center position (maintaining equal lengths
of feedline) will allow both antennas to be fed in phase, resulting in a
nearly omnidirectional pattern. You'll get about 3 db of gain with a
nice null directly off the back.

I used this scheme to advantage when I lived on a city lot in Cincinnati
for a number of years.

Dave K8MN