[RFI] Guidance on finding noise?

[AA5CT]

 This may be a case where the marine DF receiver succeeds, and a
simple DF loop fails.


With the simple DF loop one is unable, repeat, *unable* to resolve 
the __180 degree ambiguity__ that the 'null' of a simple loop gives. 


The BIG, and this is NO slight advantage offered by the marine DF 
receiver is the utilization of a "sense" antenna that works in combination 
with the built-in loop antenna to 'synthesize' a cardioid or unidirectional 
antenna pattern. 


WITH THIS feature one can actually 'sweep' around the compass rose 
and get a feel for where the strongest noise is coming from, like pointing
a Yagi antenna around, but on 160 or 80 meters! On the other hand, the 
simple loop can ONLY give a one a NULL, and there remains the choice
of which direction, which bearing the 'source' lines in, because of that 
180 degree ambiguity. 
 

Also with the simple loop one cannot 'scan around' for the strongest 
signal, whether that signal is a 'broad band' white noise (LIKE I get 
from a car wash in my area) OR impulse 'buzz' noise from power 
line arcing sources. 


IT REALLY IS pretty cool to 'twirl' the direction knob on one of these 
Coastal Navigator Marine DF receivers and HEAR the different 'arc' 
signatures or sounds coming from different directions. 


Maybe this is where we're getting hung up up? All my DFing for 
any noise nowadays makes use of the marine DF receiver with the 
sense antenna and that directional Cardioid pattern. 


If IT emits, its a simple matter of taking two bearings sufficiently 
spatially spaced apart and "x" marks the spot of the source. I now 
use Google maps and 'null' bearings taken from my DF receivers 
to pinpoint distant sources.


One technique I've used too is to 'set out' after one of these sources on
my trail bicycle, and through the use of null DFing and the Sense/Cardioid
function eventually locate OR determine the source is further way than
first thought. If I get down the road a mile or so AND the DF receiver is
still indicating the SAME direction, I'm looking at a source that is now 
on the order of 4 to maybe 5 miles way, and as I've written, I've had a 
couple just like that!


de AA5CT

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     On Saturday, January 11, 2020, 9:03:04 PM CST, Kenny Silverman <kenny.k2kw at gmail.com> wrote:  
 
 KC4D,N3AC and N3CW went hunting with a KX3 and a DX Engineering Amplified RX loop and again didn’t find anything conclusive. Basically they said the loop performed about the same as one of the AM radios we have that’s fairly directional. 

We’ve been looking so many times that we’re getting frustrated.  There are a few noisy clusters, but we can’t find a specific pole or house.  Nor can we assess if the noisy areas are actually the key offender(s)

Do we call in the clusters we found ?  Or do we really need to pinpoint the source(s) better before we ask for crews to come out?  We’re concerned about crying wolf and/or giving a list of more than a dozen poles for the power company to look at. 

Regards , Kenny K2KW 

P.S.  the only success so far is fixing my subject line typo 🤓