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I've run CP on antennas ranging from the PDL-II to the Laser 400 and can't say I ever missed those 3db when working skywave propagation. Skip is constantly changing polarity and you'll never notice it unless you have a coax switch on a dual polarity beam. When a 20db signal drops to S-9 within seconds it's usually because the polarity of the skip signal has rotated away from the one your antenna is in. Flip to the opposing polarity during that signal drop and watch the signal come up as it falls in the other polarity.

Then you will see the value of CP in skip conditions. You are no longer subjected to the 20db drop that a complete cross polarization condition would create and it only cost you 3db to avoid the 20db drop that happens regularly with linear polarized antennas in skip. Skip signals remain noticeably more stable in CP. The one tip if you're considering CP is that everything on the antenna must be symmetrical other than the 90 degree delay line in order to form real CP. Don't use one piece of old coax and a new type on the other side. Velocity factors of both cables must match or your delay will be offset as a result.

I've also noticed that if you try and "follow" skip with a coax switch as it's changing polarity, there is a period of time where the signal is low on both vertical and horizontal. That is when the signal is directly between vertical and horizontal. Here the CP antenna can show a higher signal than either vertical or horizontal alone since the CP signal is in all polarizations, simultaneously.

<blockquote data-quote="Shockwave" data-source="post: 663801" data-attributes="member: 10882">I&#039;ve run CP on antennas ranging from the PDL-II to the Laser 400 and can&#039;t say I ever missed those 3db when working skywave propagation. Skip is constantly changing polarity and you&#039;ll never notice it unless you have a coax switch on a dual polarity beam. When a 20db signal drops to S-9 within seconds it&#039;s usually because the polarity of the skip signal has rotated away from the one your antenna is in. Flip to the opposing polarity during that signal drop and watch the signal come up as it falls in the other polarity.Then you will see the value of CP in skip conditions. You are no longer subjected to the 20db drop that a complete cross polarization condition would create and it only cost you 3db to avoid the 20db drop that happens regularly with linear polarized antennas in skip. Skip signals remain noticeably more stable in CP. The one tip if you&#039;re considering CP is that everything on the antenna must be symmetrical other than the 90 degree delay line in order to form real CP. Don&#039;t use one piece of old coax and a new type on the other side. Velocity factors of both cables must match or your delay will be offset as a result.I&#039;ve also noticed that if you try and &quot;follow&quot; skip with a coax switch as it&#039;s changing polarity, there is a period of time where the signal is low on both vertical and horizontal. That is when the signal is directly between vertical and horizontal. Here the CP antenna can show a higher signal than either vertical or horizontal alone since the CP signal is in all polarizations, simultaneously.</blockquote>

[QUOTE="Shockwave, post: 663801, member: 10882"] I've run CP on antennas ranging from the PDL-II to the Laser 400 and can't say I ever missed those 3db when working skywave propagation. Skip is constantly changing polarity and you'll never notice it unless you have a coax switch on a dual polarity beam. When a 20db signal drops to S-9 within seconds it's usually because the polarity of the skip signal has rotated away from the one your antenna is in. Flip to the opposing polarity during that signal drop and watch the signal come up as it falls in the other polarity. Then you will see the value of CP in skip conditions. You are no longer subjected to the 20db drop that a complete cross polarization condition would create and it only cost you 3db to avoid the 20db drop that happens regularly with linear polarized antennas in skip. Skip signals remain noticeably more stable in CP. The one tip if you're considering CP is that everything on the antenna must be symmetrical other than the 90 degree delay line in order to form real CP. Don't use one piece of old coax and a new type on the other side. Velocity factors of both cables must match or your delay will be offset as a result. I've also noticed that if you try and "follow" skip with a coax switch as it's changing polarity, there is a period of time where the signal is low on both vertical and horizontal. That is when the signal is directly between vertical and horizontal. Here the CP antenna can show a higher signal than either vertical or horizontal alone since the CP signal is in all polarizations, simultaneously. [/QUOTE]

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