"Brian Howie" wrote
...
In message , Dave
writes

"Szczepan Bialek" wrote in message
...
It seems that at long distances should appear the phenomenon of
frequency doubling.
See: http://www.rp-photonics.com/frequency_doubling.html

Is such?
S*
not that has been reported anywhere i have seen. this is likely because
that at the low amplitudes of radio waves relative to the energies needed
to create non-linear effects the medium is close enough to linear that any
doubling effect is too small to see.


You can get ionospheric mixing of radio waves. e.g Luxembourg Effect; so
doubling is possible.

I also once heard a mixing effect of the 10MHz Time signal MSF with the
60KHz time signal ,producing two sidebands at 10.060 and 9.030 MHz, but
that could have been an effect at the transmitter site.

Maybe WWV does the same - take a listen; it's not strong enough here.

My knowledge on radio waves starts and ends on the description of the Hertz
experiment. So my questions apply to the half wave dipoles.
In the acoustic analogy the Hertz emitter (dipole with the two big balls on
its ends) works like the two monopoles halve wave apart (of course not in
phase). In a few meters from it the Hertz receiver (ring with the two small
balls) works only if parallel. When the receiver is parallel with the
emitter the spherical wave from the upper ball push the electron to lower
halve of the
receiwer and the small spark jump. The frequency is the same
In other orientations the electron in the ring are also moved but the
voltage is equal and no sparks.

But at long distances on every piece of metal acts the two alternating
electric field from the two monopoles. The frequency must be doubled.
Are now antennas similar to Hertz dipole?
Is the frequency doubled.
S*