[RFI] Powerline Bandwidth Characteristics

[G. White]

Hope you can help:

In trying to resolve several different interfering sources, I am wondering about how to best identify powerline noise vs other types.

I always believed Powerline noise to be be very wide band, sounding similar throughout most of the HF band. Or at least, several bands. Is this correct? 

I seem to get confused when I hear powerline type noise, but only at  certain frequencies- and at differnt bandwidths... anywhere from a 5 -100KHz bandwidth, for example. So is it possible that the nature of the arcing, flashover or corona is resonating within specific bands and/or at specific frequencies - or is that highly unlikely?

I have often re-evaluated my long time belief that :"if its powerline noise, its has to cover the entire HF band"

thanks and looking forward to your repy

Greg