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
Some of the line-conducted emissions can radiate from the power distribution
circuits - especially with overhead service
Charlie, K4OTV
-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of N1BUG
Sent: Saturday, November 09, 2013 6:29 PM
To: Rick ve3mm
Cc:
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 m
Some switching power supplies are frequency-jittered to spread their
spectrum and enable their host devices to meet FCC or Industry Canada
line-conducted emissions limits. Also some of the newer lighting devices and
cicuits can produce RF!! Y ou might try walking your neighborhood with a
portable
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 p
I shut down all of the circuits in my house other than my shack and it did
not disappear.
Has anyone experienced something similar?
Constantly. You took the right first step and determined that the noise
source is external to your home. From here, the real work begins. Trying
to get an opi
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
