Topband
[Top] [All Lists]

Re: Topband: beverages

To: Tom Rauch <w8ji@contesting.com>, topband@contesting.com
Subject: Re: Topband: beverages
From: Herb Schoenbohm <herbs@vitelcom.net>
Date: Sun, 23 May 2004 11:43:48 -0400
List-post: <mailto:topband@contesting.com>
Tom;

Would you not consider a circular polarized antenna capable of diversity reception? Also I recall reading some time ago that in theory a RHCP signal into a LHCP antenna has almost infinite rejection. I have never heard of amateurs using CP for anything below VHF and UHF space communications. However, today in the broadcast business CP is almost a given even though you loose about 3 db in the process. You buy it back in signal stability especially with multipath and vehicular circumstances.

I can't imagine, however, anyone constructing a helix array for 160, but crossed turnstile dipoles are not impossible. I just wonder what CP would buy you on rapidly fading signals and arrival angles that occur on top band.

73,

Herb Schoenbohm

Tom Rauch wrote:

Diversity requires a voting system or some equivalent and
separate channels, like stereo with two antennas far apart
and your brain doing the addition of signals. Otherwise you
actually increase fading by adding signals.


You just can't add signals together from a large area and call it diversity. It doesn't work at microwave, it especially doesn't work at HF.

73 Tom


_______________________________________________ Topband mailing list Topband@contesting.com http://lists.contesting.com/mailman/listinfo/topband




_______________________________________________ Topband mailing list Topband@contesting.com http://lists.contesting.com/mailman/listinfo/topband

<Prev in Thread] Current Thread [Next in Thread>