said by utahluge:as most built-in antennas are hit or miss if they are H/V. Being at 45* off a true H/V may be just enough to catch the signal coming from an antenna in a true H/V setup as there is no true H or V radiation.
No, the standard biquad isn't circularly polarized, and a 45 degree polarization isn't the same as circular polarization.
What I meant about voltages is that the polarization direction is by definition the direction of the electric field. If you look at the biquad antenna, you can see that there must be a voltage gradient across the center of the antenna, hence that is the direction of the electric field at that point. This is because one side of the center is grounded (coax shield), and the other has the signal voltage applied to it (coax center).
It's not always that simple; as the document you found said, interaction of active elements and other factors can also affect the polarization. But the biquad is a pretty simple antenna with one active element and a flat ground plane, so it probably IS that simple in this case.
The circularly polarized biquad looks like this
+-----+ +-----+
| | |
| | | |
| +-||-+ |
| | | |
| | |
+-----+ |-----+
(feed is across the || in the center)
and if you know how that works, you're better at this than I am.
Your H-antenna would probably have a much lower impedance than a square loop, and thus wouldn't work very well. The biquad with reflector is nice because its impedance is naturally very close to 50 ohms, so you can use a coax feed with no extra hardware.