[sdiy] generators/antennas analogy?

[John L Marshall]

I'm skeptical.

If the farmers antenna was within the "near field" of the broadcast antenna
then the farmers antenna could act a parasitic element to the broadcast
antenna. Near field is usually considered to be less than ten wave lengths.
At ten wave lengths distance from a typical broadcast antenna induced
current to a resonant parasitic element will be milliamperes.

The effect of a parasitic element would be detected two ways. Tower current
and phase would change. Field strength readings would change.

Parasitic elements is how Yagi-Uda antennas achieve gain and directivity.
The parasitic elements in a Yagi-Uda antenna are generally a quarter to a
wave length from the driven element.

If you would like to simulate the effect of radiating elements and parasitic
elements, I highly recommend EZNEC http://www.eznec.com . I used this
program to determine if cellular base station towers would cause an
influence to nearby AM broadcast stations.

> Some years ago a farmer got busted who was "stealing" emitted
> radiation from our national radio/tv network's antennas at Wavre,
> Belgium .  He reportedly used big arrays to capture the energy and
> heat his greenhouses this way .
>
> No idea how the guy got detected tho .