On Mar 21, 6:26 pm, K7ITM wrote:
On Mar 21, 3:08 am, Artem wrote:

Sources is not grounded.

Yes, unfortunately noise that is generated more than one or two
wavelengths away from your antenna will be almost entirely
electromagnetic by the time it reaches your antenna. Antennas do not
differentiate between "electrically generated" and "magnetically
generated" noise, when you are far enough that the electromagnetic

I did not hear nothing about electrically or magnetically photons.
It's just photons.

field dominates over any near-field electric or magnetic field. The
balanced small loop is good for rejecting electric-field noise only if
(1) the noise is generated close to the antenna and

Yes. Computer, lamps etc close to antenna.

(2) the antenna is
close to the ground (so the electric field is guaranteed to be nearly

15 floor of 16-floor building. But I think that in this case "ground"
are building walls.

vertical) -- -- where "close" means relative to a wavelength. So the
small balanced loop is especially good for LF and VLF work.

my reason was make narrow-band antenna. For reject all out of band
noise.


Perhaps someone else will have suggestions about what else you might
try.

Cheers,
Tom