I often find the statement that noise from electrical appliances has
mainly vertical polarization. Would anybody be so kind to explain
why?. Thanks!
Daniel Perez

On Jan 7, 7:50 pm, lw1ecp wrote:
I often find the statement that noise from electrical appliances has
mainly vertical polarization. Would anybody be so kind to explain
why?. Thanks!
Daniel Perez

At the surface of a perfect conductor, the electric field must be
perpendicular to that surface. To the extent that ground is a good
conductor, the electric field will be predominantly perpendicular to
the surface of the ground. That is true of signals as well as noise.
If you sense the electric field within a fairly small fraction of a
wavelength of good ground, expect it to be mainly vertical.

Perhaps a more interesting thing is that commonly the noise from
appliances and the like in the near field has an electric field
component that's much larger than the magnetic field component: that
is, the ratio of the two is much higher than it is in an
electromagnetic wave. In that case, you can reject such local (near-
field) noise by using a receiving antenna that is not sensitive to the
electric field--for example, with a balanced small loop. Since you
need to be in the near field for this to give much benefit, in a
practical sense you probably won't get much benefit above perhaps
5MHz. But balanced loops (which are relatively insensitive to
electric fields) are useful at 160 meters, the AM medium-wave
broadcast band, and VLF/LF.

Cheers,
Tom