Yes, CP does cause more multipath esp. in urban environments. Turns out there
are a large number of buildings the preferentially reflect V better than H. CP
gives V energy othwise lacking (mostly) in a strictly H xmt situation. What
you get with strictly H pol. is quite a glorious & random mess of polarizations.
Neither the BBC or the Germans use CP in FM broadcast, strictly H.
Yes, 2X antenna gain or 2X power are needed to "equalize" things.
TV tried & abandoned CP due to ghosting. With color TV, the ghosting is even
more obnoxious. This I have on the authority of the VP of Engineering of one
of the largest national Canadian TV networks (he's a ham).
-
From: larynl2 <lar...@hotmail.com>
Subject: Fw: Re: [Repeater-Builder] Diversity FM reception
To: Repeater-Builder@yahoogroups.com
Date: Sunday, August 23, 2009, 11:52 AM
--- In Repeater-Builder@ yahoogroups. com, John Sehring
<wb...@...> wrote:
>
> Oh, I forgot...circular polarization would be excellent to use on VHF and UHF
> repeater. We want the extra signal strength & the multipath would be way
> less;
CP has always intrigued my for amateur repeater use, although I've not tried it
yet.
Yes there would be less multipath fading, but the "extra signal strength"
woulnd't appear unless you keep the same ERP in both H and V. And that
requires a larger antenna or double the transmitter power.
John is it really true that CP causes MORE multipath distortion in FM
broadcast?? And TV??
Laryn K8TVZ
