[RFI] Noise Level During Power Outage

[Pete Smith N4ZR]

OK, a bit of apples and oranges.  I have two powerline sources, and when 
both are active my noise level is ~s8-9 on 10 meters in AM bandwidth.

I am less than 100 yards from a very high voltage line, but to my 
knowledge it has never caused any RFI problems.  Years ago, it was 
explained to me as "if they have a leak it costs them real money."

73, Pete N4ZR

On 2/1/2023 10:32 AM, K9MA wrote:
> Don't be too envious, Pete.  Those levels are from the K4 panadapter 
> with a 10 kHz span, which means a noise bandwidth of about 20 Hz. 
> (Resolution bandwidth 11 Hz.) Besides, I have a power splitter and 
> some other stuff between the receiver and the antenna, about 7 dB of 
> loss, though I don't know where 4 of those dB come from. In any case, 
> my "good" noise level on 20 of -130 dBm corresponds to about -110 dBm 
> in a 400 Hz bandwidth, about S-3 at 6 dB per S unit.
>
> Pete is very close to a big transmission line. I have one of those a 
> couple hundred meters away, but whatever noise it causes is always 
> overwhelmed by noise from the distribution lines with which I'm 
> surrounded.
>
> 73,
> Scott
>
>
> On 2/1/2023 8:25 AM, Pete Smith N4ZR wrote:
>> I am green with envy - my local line noise is currently "only" S5
>>
>> 73, Pete N4ZR
>>
>> On 2/1/2023 12:26 AM, K9MA wrote:
>>> That table didn't come out very well at all. Here's a link to the pdf:
>>>
>>> https://sdellington.us/hr/RFI/Power%20Outage.pdf
>>>
>>> 73,
>>> Scott K9MA
>>>
>>> On 1/31/2023 11:21 PM, K9MA wrote:
>>>> 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
>>>>
>>>
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