I believe, but am not certain, that the only true CP antenna is helical in
nature and wouldn't be broadband. Perhaps it could be broadband to some
degree by increasing the size of the coils over the length of the antenna,
something like a log periodic antenna, though it would surely reduce the
gain.
I searched Google for the available of CP TV receive antennas but struck
out. Seven years ago I constructed a full power CP UHF station on Mt. Wilson
in the LA market and was able to purchase commercial grade high gain CP*
antennas to resolve cable reception issues but I can not find any such
product available today.
* = These were panels that incorporated simple vertical and horizontal
elements, as do most UHF broadcast antennas, and they worked very well.
-----Original Message-----
From: opendtv-bounce@xxxxxxxxxxxxx
[mailto:opendtv-bounce@xxxxxxxxxxxxx]On Behalf Of Manfredi, Albert E
Sent: Tuesday, June 30, 2009 3:25 PM
To: opendtv@xxxxxxxxxxxxx
Subject: [opendtv] Re: VHF Stations Seek Solutions for Reception
Problems, by Doug Lung
Thanks, Dale.
Cliff Benham wrote:
Does this also mean that a circularly polarized receive antenna is
also a *single channel* antenna as well?
Aha. I think I see what you're asking. Like, can CP antennas be used for
transmitting MIMO-like signals. Sounds like no is the answer. For that,
you want the maximum possible isolation between the polarities. Here,
ideally, they would be identical and just phase-shifted.
Bert
