"Reg Edwards" wrote in message
...
Many, if not all, FM broadcast stations in the US transmit both a
vertically
and horizontally polarized signal. So, rotating the antenna 45 degrees
is
not giving up anything.

================================

Simultaneous transmission of vertical and and horizontal polarised signals
from a single antenna system is impossible without upsetting the desired
radiation coverage pattern.

What you mean is your clever US broadcasting engineers have designed
antennas which radiate "Circularly Polarised" signals.


If you go to a broadcaster's web site, they will say X KW horizontal, and X
KW vertical, with no reference to right or left hand polarization. I take
that to mean cross polarized, rather than circular. Obviously, the reason
for the vertical component is car radios. As for messing up the pattern, I
would think that in the majority of cases they want equal propagation in all
directions

Tam/WB2TT
As Cecil says, nobody gains anything power-wise. For the same transmitter
radiated power everybody's signals are 3 dB down (half-power) relative to
simple linear polarision when both transmitting and receiving antennas
have
the same polarisation.

The advantage of circular polarisation is that it doesn't matter which
polarisation your antenna is orientated because, in practice, when
erecting
it, the polarisation received by your antenna is usually a matter of
guesswork anyway.

Only with relatively-rare, direct line-of-sight broadcasting propagation
is
there any certainty in the polarisation of received signals.
----
Reg.