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
_______________________________________________
RFI mailing list
RFI@contesting.com
http://lists.contesting.com/mailman/listinfo/rfi
--
Scott K9MA
k9ma@sdellington.us
_______________________________________________
RFI mailing list
RFI@contesting.com
http://lists.contesting.com/mailman/listinfo/rfi
|