[RFI] Noise location tools

[Karin Johnson]

I have successfully found about a dozen street lamps which had failing
sodium vapor lamps causing RFI.
The spectrum of the RFI was primarily located between about 5 MHz to an
upper limit of 8 MHz.
unique to my location and the street light installations.  The physical
construction of the street light
support is approximately 30 foot tall concrete posts.
I suspect that this height was pretty much responsible for limiting the
bandwidth of the RFI. 
I've found all of these defective lamps using a PL-660 tuned to the
strongest spectrum with
an HFDF loop for 3.5 to 8 MHz manufactured by National RF of San Diego, CA.
I take a main bearing 
from my home location then walk a short distance approximating  an estimated
90 degree offset bearing,
plot the result on Google Earth Pro, then go looking in the area intersected
by the bearing lines.  In every
case I've been able to locate the defective lamp post.   I might note that
in my case I did not hear any 
RFI at higher frequencies even when very close to the base of the street
lamp.

Karin Anne Johnson P.E. K3UU
Palm Harbor, FL


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