Here is another circular polarisation article you may find useful.
Simple construction too.

You will obviously need to recalc the dimensions from 144MHz. (Multiply
everything by 144/87.7)

http://home.comcast.net/~ross_anders...dCollinear.htm

Cheers Bob VK2YQA


For FM Broadcasting this is VERY IMPORTANT. Originally, FM
broadcasters
used horizontal polarization (usually versions of "halos" ) for their
broadcast antennas. This was fine for fixed or home listeners, who used
horizontal TV/FM antennas or folder wire dipoles (included with many stereo
receivers) - BUT cars and mobile FM receivers tended to be vertically
polarized. In order to address this 2 solutions were used -- one was to add
a vertically polarized element to a large "phased array" on the side of the
tower. The other was to replace the antenna with one that could produce
circular polarization
http://www.starantenna.com/fm_broadcast_antenna.htm

http://www.scott-inc.com/html/fmant.htm

w9gb