herbs at vitelcom.net
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
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.
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