[RFI] Noise Level During Power Outage

[K9MA]

My QTH is in an older residential area, surrounded by overhead power 
lines. Line noise is a constant problem. We recently had a major power 
outage, so I measured the noise levels to get a baseline with little 
line noise. (See below, assuming it comes through.) The outage was 
pretty large: there was no power within a kilometer or so, perhaps 
further to the west. The levels I measured shortly after power was 
restored the next morning are fairly typical lately. To the NE, it 
wasn't so bad, only increasing 5-8 dB when the power came on. West was 
much worse, 7-19 dB. I've long known there was a major noise source to 
the west. I guess it's time to track it down.

I suspect these levels are fairly typical of a residential area with 
overhead lines. They would probably be worse if I hadn't been doing 
battle with the utility for the past 30 years to get the worst of the 
sources fixed. One thing this data shows, which I've long suspected, is 
that the distribution lines are the major source of noise. There are 
some transmission lines just a few hundred meters away, but I've never 
traced any significant noise to them.

It may say something about the sad state of our utility's 
infrastructure: A car knocked down a pole about 1 km from my QTH, and it 
took out the power up to 2 km away, with power surges causing extensive 
damage to appliances, etc. (None at my place.) Just down the street, far 
from the downed pole, we had a major fireworks show and nearby a 
transformer exploded. Apparently, similar things happened throughout the 
affected area. Did they forget the fuses?

73,

Scott K9MA

-- 
Scott Ellington
Madison, Wisconsin, USA

scott at sdellington.us


K9MA 	
	
	
	
23.01.28 Noise Levels 	
	
	
	
Major power outage 	
	
	
	
MT, K4, 10 kHz span, 7 dB rx path loss 	
	
	
	
Resolution bandwidth 11 Hz 	
	
	
	

	
	
	
	
Frequency 	Bearing 	Power Out 	Power On 	
14 	45 	-135 	-130 	dBm
270 	-139 	-120 	
21 	45 	-141 	-133 	
270 	-140 	-127 	
28 	45 	-148 	-141 	
270 	-146 	-139 	

-- 
Scott  K9MA

k9ma at sdellington.us