"Lex-Lutor" wrote in message
...
| I'm interested in real results between this two antennas, urban area, same
| power, same high etc. Running circular we have only 50% of power, compared
| to normal dipole, but there are many positive feedbacks about circular
| polarization in urban area!

| Is this really true?

In a manner of speaking, yes, it's true. The reason why you have 1/2 the power
that you would with a straight dipole is because half the power transferred goes
into the other polarisation (10kW ERP = 5kW Horiz + 5 kW Vert). And the reason
why one uses vertical polarisation is for the number of automobile receivers
that have vertically-oriented antennas. But, other than that (with one
exception which I'll cover presently) there's no good reason why you'd run
C-pol. For the rare individual who has a C-pol receiving antenna, (s)he'd be
picking up both polarisations, and therefore get 3dB better
signal-to-noise....but in an urban area, that effort is for naught, since
there's already plenty of RF, and twice more than plenty is still more than
plenty. For the rest of those using dipoles in random orientations, they're
just as susceptible to multipath, fading, and other propagation effects that
would be experienced with a single polarisation. Still, there's some value in
this since it wouldn't make any difference which orientation a simple dipole was
in, if it had a C-pol signal to work with.
--
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Men born to freedom are naturally alert to repel invasion of their liberty by
evil-minded rulers. The greatest dangers to liberty lurk in insidious
encroachment by men of zeal, well-meaning but without understanding." -- Justice
Brandeis
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