[Premium-Rx] E field & H field antenna question

[Terry O']

I'm noticing some things I don't understand between my new H field loop 
and my reliable E field T2FD.  Because of the extremely high noise 
levels from some neighbor's house ranging well over 15 MHz some days, I 
built a 1 meter loop with a simple preamp.

It works like a charm on the noise, dropping it way down while having 
minimal effects on signal strength.  The effect is clearly visible on 
the SDR spectrum screen as the hoards of vicious clustered spikes 
basically disappear.  What little noise that remains has lower pitch and 
it is much easier to hear weaker signals over the top of it.

But from the loop, the SDR spectrum display also shows broad splotches 
of noise, 50-100 kHz wide, that are in no way evident on the spectrum 
from the T2FD antenna.  When I tune into them sound like a low pitched 
white noise.  These splotches are not harmonically related to each other 
or to the concentrated hoards of raspy spikes from the QRM.  The loop is 
powered by a quiet 12 VDC gel cell so the power is not the source.

Anybody ever see anything like this with an H field loop?  I can send a 
screen shot where I flip an A-B switch from the loop to the T2FD that 
clearly illustrates what I am hearing.

73,
Terry O'
WB9GVB