Topband: beverages

Herb Schoenbohm herbs at
Sun May 23 11:43:48 EDT 2004


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.


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
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