Well it's certainly common to extract a non-H/V polarization into these
components to do easy mathematical operations. The only reason it is
legit to do these operations is that they are equivalent.
Tom Rauch wrote:
> > I have modeled quad loops for dual polarization (H and V) and contrary
> > to W8JI claims and others, they have dual polarization components
> > nicely filling nulls in the pattern of the "other" polarization. I had
> > 3 el. dual polarization quad mounted over salt water on the boat ramp,
> > half wave up, 90% of the time beating 4 square over "salty beach
> > sand."
> Hi Yuri,
> The reason you see that "dual polarization" is because Eznec only
> considers the polarization as two pure distinct polarizations.
> When you have a tilted wave, it shows up as a mixture of V and H
> even though it is actually a plane wave of one pure polarization.
> If you stood out in front of the antenna with a small antenna and
> checked the radiation, what you would find is a peak at some angle
> other than flat or vertical, and a perfect null 90 degrees from that tilt.
> The only way to get two distinct polarizations at the same time is
> to excite two similar antennas mounted at right angles in the same
> physical location with 90 degree phase shift, to mount a small loop
> with a small complementary dipole running through the axis and
> feed them both in phase, or to stagger two right-angle antennas 90
> degrees distance and feed them in phase.
> In those cases, you will generate a circular rotating wave.
> It is physically impossible to generate more than one polarization
> in any given direction at the same time without doing one of the
> above, and without a rotating wave (circular polarization). People
> wrongly think it happens because modelling programs display
> results as mixtures of pure V and pure H when the wave is actually
> just skewed. 90 degrees from that skew the field is zero, so you
> have a single polarized wave that is simply tilted.
> For example, a horizontal dipole has a perfectly horizontal electric
> field broadside. As we move off towards the ends, the wave starts
> to "tilt". Straight off the ends, the electric field is vertical. But it has
> ONLY one polarization in any point in space looking back at the
> antenna. A loop is no different, neither is a Carolina Windom,
> neither are a vertical and dipole that are centered and fed in-phase.
> 73, Tom W8JI
> List Sponsored by AN Wireless: AN Wireless handles Rohn tower systems,
> Trylon Titan towers, coax, hardline and more. Also check out our self
> supporting towers up to 96 feet for under $1500!! http://www.anwireless.com
> FAQ on WWW: http://www.contesting.com/FAQ/towertalk
> Submissions: email@example.com
> Administrative requests: towertalk-REQUEST@contesting.com
> Problems: firstname.lastname@example.org
List Sponsored by AN Wireless: AN Wireless handles Rohn tower systems,
Trylon Titan towers, coax, hardline and more. Also check out our self
supporting towers up to 96 feet for under $1500!! http://www.anwireless.com
FAQ on WWW: http://www.contesting.com/FAQ/towertalk
Administrative requests: towertalk-REQUEST@contesting.com