It so happens my 10ft diameter multi turn LF loop is now plonked in the centre of an extensive earth mat consisting of bonded welded fence wire, and about 100 x 100ft radials, numerous Earth rods etc part of the MF tx system - Cant detect any diode type effects from the mat....
 
Ive noticed since the loop has been surrounded by this "mat" the induced noise into the loop has increased and the loop effectiveness at 137kHz  has been severely compromised  (about 5dB on Transpolar paths over an optimized positional L400B)  - the mat and the loop are above 2.5 metres apart  and not electrically connected (galvanically isolated) with common mode chokes on the 400 coax -  there is no local coupling from the MF Marconi ie I can short it to ground or bring it down and the background noise (somewhat White in nature around -95dBm) doesn't change....
 
So I just wondered if I should move my loop to a new Green field location away from the radial mat etc - anyone else noticed similar?? Any suggestions?
 
Thanks
Laurence KL7L et al
ps over the pole is poor this evening so far with a little spreading...