Home |
Search |
Today's Posts |
#6
|
|||
|
|||
If you put the array on a rotator and put a receive antenna with some
sensitive output indicator beyond the near field, you can plot relative field, and thus accurate F/B by adjusting the power to the antenna for same received F/S at, say, 10º increments. Nothing else should change, so the relative field strength in the various directions should relate to each other. Ground reflections and absorption, and all the other artifacts will be constant unless you change something else. ok, that sounds like a good idea, with the rotator, keeping everything else the same. This site: http://radioproshop.com/antennaconcepts.htm Says that the near-field is defined by Rmin=(2*D**2)/wavelength, where D is the largest dimension of the antenna. So if we roughly say one wavelength is 10 feet, and the largest dimension is the dipole, then we get Rmin=5 feet, or about a 1/2 wavelength. This sounds a bit too close to me, perhaps the far-field is better defined as, like, ten wavelengths or so? Also, i don't really have a transmitter that I can vary the power that much...maybe that's something i should make or get. Something variable at least by 20dB or so. Slick |