"CWB" wrote
FM stations USUALLY use Circular Polarization.....
(similar to horiz and vertical at the same time...)
so an antenna set for horiz or vertical will work
(but lose 3db of signal compared to a CP antenna!)
________________

FM broadcast stations in the US _must_ radiate their licensed h-pol ERP
regardless of the ERP they radiate in other polarization planes. However
for most omni FM stations, v-pol RMS ERP cannot (legally) exceed h-pol RMS
ERP.

The gain of a true c-pol transmit antenna is 3dB lower than for the same
configuration of linearly polarized radiators. However in FM broadcast, the
transmitter power is increased by 3dB to make up for that, and h-pol ERP is
the same for either antenna configuration. Therefore the h-pol field
strength produced by either transmit antenna over the same path should be
the same.

Using a c-pol antenna to receive a c-pol FM station would add 3dB to the
signal seen by rx (over a free space path), as well as reduce the
self-interference caused by multipath.

RF

Visit http://rfry.org for FM transmission system papers.