[Lowfer] What kind of antenna ?

[listread at lwca.org]

>
> https://www.youtube.com/watch?v=C65u7Pmz7a0
>

A very good demonstration of feedline induced noise effects and their
remedy...and also, if you think about it, pretty conclusive proof that
loops are not "magnetic sensors" except for energy stored within the near
field of a source (ie, noise), and that whips are not "electric sensors"
except in the near field.

And for that matter, a whip on a pole with a connection to ground is
scarcely a probe, "e" or otherwise; it's an earthed off-center-fed dipole
at best, and if the shield is not isolated from ground at one end or the
other, then it's also a loop antenna with mutual coupling to one side of
the whip input.  Not a worthwhile loop, either... one that's too low to
contribute to signal pickup, but is instead in a fine position to couple
noise from the end nearest the house into the rest of the antenna.

Breaking up that loop with an isolated power source so that only one end
is grounded, as Doug did, and/or deploying other isolators inline, are
recognized solutions for this problem that (I have lately discovered) date
back to World War I.

John