Looking for an old project based on two half wave vertical dipoles by W7DE...
 

Some years ago I used to buy 73 when it was available in my hometown in
Italy. I mostly liked antenna projects and ardf articles. Once I saw an HF
antenna called "the palm phased array", the "California phased array" or
something like that, engineered by Dave Evison W7DE. It was based on two
vertical dipoles strung onto two palm trees. Is there any source where I can
find this project? Thanks a lot for any help, it would be useful.
Francesco ik8vwa

--

Looking for an old project based on two half wave verticaldipo...
 

Francesco L., IK8VWA wrote:
"Once I saw an HF antenna called "the palm phased array",---. It was
based on two vertical dipoles strung onto two palm trees."

Sounds like a Franklin antenna, also known as a colinear array. Vertical
radiation pattern from a radiator that grows beyond 180-degrees starts
producing an undesired high-angle lobe in addition to the signal
radiated at low angles to the earth`s surface. The undesired radiation
is produced when current in the radiator reverses direction at the
180-degree mark. If we introduce a phase inverting device at the
180-degree mark on the radiator we increase radiation perpendicular to
the longer radiator without growing a high-angle lobe.

Many VHF colinear antennas use 1/4-wave stubs as phase inverters between
1/2-wave radiating sections. A resonant L-C circuit can be used in place
of a 1/4-wave short-circuit stub. A transformer can also be used to
reverse the phase as can various line feeds.

In the "International" edition or 3rd edition of Kraus` "Antennas" on
page 824 in Fig. 23-21(b) is shown a dipole made of (4) 1/2-wave
sections. It uses (2) self-resonant coils. Each coil separates a pair of
1/2-wave radiators so that all four radiators have current flowing in
the same direction through them at the same time.

Everyone needs access to the newest 3rd edition of "Antennas".

Best regards, Richard Harrison, KB5WZI

Looking for an old project based on two half wave vertical dipoles by W7DE...
 

On Mon, 18 Feb 2008 22:56:36 +0100, Francesco L. wrote:

Some years ago I used to buy 73 when it was available in my hometown in
Italy. I mostly liked antenna projects and ardf articles. Once I saw an HF
antenna called "the palm phased array", the "California phased array" or
something like that, engineered by Dave Evison W7DE. It was based on two
vertical dipoles strung onto two palm trees. Is there any source where I can
find this project? Thanks a lot for any help, it would be useful.
Francesco ik8vwa

I have found the article and can copy and email it to you.
Is the email address above good with the nospam removed?
73 de VE3JUA

Looking for an old project based on two half wave vertical dipo...
 

Richard Harrison wrote:
In the "International" edition or 3rd edition of Kraus` "Antennas" on
page 824 in Fig. 23-21(b) is shown a dipole made of (4) 1/2-wave
sections. It uses (2) self-resonant coils. Each coil separates a pair of
1/2-wave radiators so that all four radiators have current flowing in
the same direction through them at the same time.

Richard, that graphic is redrawn on my web page at:

http://www.w5dxp.com/current.htm

The first two sections of that page are quotes from "Antennas"
by Kraus. The second section illustrates the above antenna.
And I don't think Kraus was using the lumped circuit model for
those coils. :-)
--
73, Cecil http://www.w5dxp.com

Looking for an old project based on two half wave vertical dipoles by W7DE...
 

I have found the article and can copy and email it to you.
Is the email address above good with the nospam removed?
73 de VE3JUA

I received the article perfectly and as you can imagine the address worked
perfectly. Thanks a lot, that was a very very kind gesture. I also wish to
say thanks to the other two hams who tried to explain what I was looking
for, anyway VE3JUA found exactly the article I referred to.
Thanks again for your kindness.
ik8vwa/2
Francesco