"christofire" wrote in message
...
"Jerry" wrote in message
...

"Harry H" wrote in message
...

The Lindenblad has an overhead null that you might find anoying for
some high elevation passes of LEOs.
Are you open to trying to build a DCA (which is an antenna that I
developed)? I make the claim that there is no other hemispheric
coverage antenna design that performs better than a DCA. But, I sure
am open to being corrected.
The Feb 2008 QST contains an article on the DCA antenna design
concept.
It is my claim that a DCA is extreemely forgiving of construction
errors and uses 4 wire dipoles and 50 ohm coax with 5 RFI type ferrites
as "baluns'.

Jerry KD6JDJ
Given the fact I don't subscribe to QST, domicile Australia, would you
have a copy of the article?

HH


Hi HH

It would be my pleasure to disclose any/all the information I have
relating to the DCA antenna design concept. It is simple. It is two
pairs of crossed dipoles. Each pair is spaced 1/4 wave apart and fed in
phase. One pair is physically mounted 90 degrees from the other pair. All
four dipoles are tilted 30 degtrees from vertical. One pair is fed 90
degrees later than the other pair.
The concept is so simple and straightfoeward that it is probable that
the concept has been developed before I thought of it. But, I have been
unable to find anything published related to this simple "Double Cross
Antenna"
I told my *Internet buddy*, Patrik Tast, in Finland about the concept
and he found it to be exactly what he needed for reception of NOAA
weather satellite signals. Patrik publishes alot of what I send him
related to the antenna. Patrik shows a section of his web page to
describe the DCA to anyone interested. You can find the QST article in
the section Patrik identifies as ANTENNAS on the first page of his site
http://www.poes-weather.com/index.php.

If you have any questions about the DCA concept you are free to E-mail
me, anytime. Or, if you have any facts or data to show where I am wrong
about how well this antenna performs, or know of something that performs
better, please set me straight.

Jerry KD6JDJ


... but surely this is the same as a Lindenblad array? The tilt of the
dipoles was always a parameter in the Lindenblad, so I wonder how your DCA
differs from what N. E. Lindenblad described in the April 1941 edition of
'Communications'.

Chris


Hi Chris

Several, well educated, antenna experts insist that the DCA is actually a
Lindenblad. If you thought the DCA is a Lindenblad, you are not alone.
The DCA is not a Lindenblad. The array of four dipoles in a Lindenblad
are fed to produce an overhead null. The four dipoles in a DCA are fed to
produce no overhead null. The DCA is a hemispheric coverage CP antenna.
The Lindenblad is not.
Let me know if you have reason to consider the DCA to be the same as a
Lindenblad. I knew nothing about Lindenblad until after recognizing the
DCA concept.

Jerry m KD6JDJ

Jerry