[VHFcontesting] Attenuation from polarity mismatch (Re: C6AFP Six Meter Beacon

[Buddy Morgan]

 As everyone else said, it depends. For ionospheric propagation, it probably makes little difference. I once had two ten meter dipoles. One vertical and one horizontal. I could switch rapidly between them. With skywave propagation, usually a station would fade in on one and fade out on the other. I could not tell that one was better than the other. However, a circularly polarized antenna would have, I'm sure almost eliminated the fading. For ground wave propagation, on 10 meters, the polarity isolation seemed to be 12~15 db. 

The higher in frequency, you go, the affects of surrounding objects is less. So, you tend to see more polarity isolation. Six meters, for ground wave operation seems to be about 15 db. I'm sure that 6M would behave pretty much like ten meters, for skywave signals. 

Close in signals, on 2M, seem to exhibit about 20 db of isolation. For long haul tropo, I'll be the diversity is a lot less. I have seen more isolation, on the higher bands. I once had a 23 cm ground plane and a LY. Best I could tell, there was about 30 db of isolation. One person tells me that 21 db was as much isolation he has ever seen on any band. I read somewhere that under laboratory conditions, on 10 GHz, 80db has been measured. 

Theoretically it is infinite. In the real world, or at least in my world, it is 12~30 db. 

Buddy WB4OMG  

 

 

-----Original Message-----
From: Peter Laws <plaws0 at gmail.com>
To: vhf contesting <vhfcontesting at contesting.com>
Sent: Sun, Jan 29, 2017 3:48 pm
Subject: [VHFcontesting] Attenuation from polarity mismatch (Re: C6AFP Six Meter Beacon

On Sun, Jan 29, 2017 at 10:38 AM, Buddy Morgan via VHFcontesting
<vhfcontesting at contesting.com> wrote:

> Of course, I am horizontally polarized.


Undoubtedly, that makes a difference ... but how much?