The switching frequency of switching power supplies can vary with the burden
on the supply as well as ambient temperature. If it's sensitive to outdoor
temperature could be the electric utility meters - most of those contain
switching power supplies these days, and the meter's internal temperature
tracks up and down with ambient temperature. Other candidates would be
electric utility load control equipment, control electronics in heat-pumps
etc., and electronics associated with satellite receivers.
Good luck!
Charlie, K4OTV
-----Original Message-----
From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of N1BUG
Sent: Saturday, November 09, 2013 6:29 PM
To: Rick ve3mm
Cc: topband@contesting.com
Subject: Re: Topband: Local noise source identification
I realize this won't help but I have a similar noise. Mine is about
24 kHz wide and drifts up/down considerably more than yours. The drift seems
related to outside temperature. Here's the real kicker:
it goes away every year immediately upon the coming of snow cover, but does
not return until mid-summer sometime. This has been happening for at least
five years now. I've tracked it to a group of
4 or 5 houses on the other side of a river, about 1000 feet from (some of)
my Beverages.
Sidebar: With a portable receiver I can also detect it re-radiating from my
100 foot vertical, which is 1500 feet from the source.
Good luck, and let us know if you find it.
73,
Paul N1BUG
On 11/09/2013 05:15 PM, Rick ve3mm wrote:
> I am looking for suggestions to help identify a local noise that I am
> experiencing on topband.
>
> It's characteristics are;
> - bandwidth approximately 15 kHz
> - amplitude relatively constant
> - centre frequency seems to vary in small steps over time, no real
pattern.
> - right now the centre frequency is 1819 kHz, it moves up and down up
> to 7 or 8 kHz.
> - does not seem to be present during the day. At least not this afternoon.
>
> I shut down all of the circuits in my house other than my shack and it
> did not disappear.
>
> Has anyone experienced something similar?
>
> 73
>
> Rick ve3mm
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