"Richard Fry" wrote in message
...
On Nov 29, 2:18 pm, Roy Lewallen wrote:
Jerry wrote:
Just for conversation, I submit that an antenna with good hemispheric
CP coverage could be made with 4 dipoles.

Yes, there's the quadrifilar helix which I believe fits that
description. Another, which I built decades ago at 450 MHz, is the "skew
planar" antenna which resembles a cloverleaf but with the "leaves"
rotated 45 degrees...

Getting back to Jerry's idea - yes, four linear dipoles can generate
nearly perfect omnidirectional c-pol. This is a design of Nils
Lindenblad many decades ago, and I've done some NEC-2 modeling of it.
The link below leads to a rendered view of that model.

http://i62.photobucket.com/albums/h8...adRendered.gif


RF

Hi Richard

The Lindenblad is Omniazimuth CP. The QHA is hemispherical CP. Some
explanation of the DCA is shown in the Feb 2008 QST.

Jerry