[RFI] Quidance on finding noise?

[Kenny Silverman]

Hi and thanks in advance!

We’ve been trying to track down some noise at a friends house but no luck so far and I was hoping for some tips on finding it.  The buzz comes on at sundown and turns off at sunrise. It’s bad on 160 but it can be heard Lightly on 80 and 40.  The noise is constant and does not cycle (at least for the 90 minutes I was listening to it tonight).  The worst direction is on the East beverage on 160. On 80m it seemed like the worst was to the NW...  it could be 2 sources but the noise appears to come on at the same time in all directions,  not a staggered turn on/off.   Could be a single source but poor F/B on the beverages. The Listening to the ARRL RFI files it sounds like power line noise or street lamps ( but without the cycling).  Over the 90 minutes tonight there were almost no variations (except for an occasional change in pitch). 

We've DF’d on a portable AM radio, 2m and ultrasonic device. AM identified some noisy poles but we’re not convinced these are the main offenders.   Not much luck with VHF or ultrasonic.  Our next plan is to use a KX3 on 160m and a decent RX loop to direction find and triangulate. 

  I suspect we’re not looking out far enough...  suggestions on how far away we should be looking?  And how close do we need to be to hear it on  VHF?

 Besides power lines and street lamps, other thoughts on possible offenders? Most of the area is residential with street lamps on most streets. 

Regards , Kenny K2KW