[RFI] 30m noise problem

dalej dj2001x at comcast.net
Thu Apr 22 03:17:59 PDT 2010

Hello Jerome,

Good .wav files and good scope pictures.

I have a similar noise here around 10 Mhz too.  I believe it is a  
light dimmer in my immediate neighborhood or a switching PS used in  
some type of lighting.  I did have line noise very badly here, which  
was worse on 10 meters and 2 meters, we, the power company and I  
together found loose hardware on a pole within a block of my house.   
The line noise was worse in windy weather, very intermittent, buzz,  
buzz, buzzzzzzzzzzzzz etc.  Does your noise get worse on 10 meters?   
If you don't have an antenna for ten then it may seem like it is  
less.  If you have a directional antenna for 10 you can try turning it  
360 degrees to get a heading, it might work also to some extent on 10  
Mhz, worth a try.  If it's on 24/7 it could be a computer PS or a  
neighbors lights that are on all the time.  Notice houses with lights  
on 24 hrs/day?  I'm just guessing of course, but these are the things  
to watch for.  It is frustrating business tracking down interfering  
noise.  I remember when, years ago of course where there was hardly a  
local noise to be found on any of the bands, but that was a loooong  
time ago, hi.  Lots of electronic gadgets now of questionable mfg.  I  
wish our (U.S.) FCC would get after mfg of these devices, prod them to  
spend a few pennies on rfi proofing the stuff.

I'm betting on at dimmer or switcher somewhere close to you.

Good luck
Dale, K9VUJ

P.S. FYI I use an Alinco DJ-G7 handheld for noise looking.  It has AM  
mode, plus a 4 step attenuator.  I need a small directional 2 meter  
antenna now for closer finding ability while walking the area looking  
noises.  It will also tune 10 mhz.

On 21, Apr 2010, at 21:38, jerome schatten wrote:

> Greetings -- I was directed here by Roger K8RI after starting this
> thread on the AMPS reflector.
> I have posted three bandscope photos of 30 my noise problem and four
> wave files using AM, FM and SSB detectors at:
> http://www.ehpes.com/noise/noise.html
> The noise has been with me 24/7 (except for one short break I had: one
> day of no noise a few days ago). That said, it peaks at 10.1 mhz and
> tails off to no problem at 6.5 mhz and 12 mhz. The train of spikes
> starts abruptly as you will see and repeats every 68-70 khz. The train
> moves slowly up and down maybe 50 khz in an hour.
> I've run the transceiver on battery power and shut off the main house
> breaker with no change in noise.
> Perhaps the unusual high amplitude start and tail off to nothing in 70
> khz will mean something to someone?
> I've been using a portable sw radio in the immediate neighborhood  
> tuned
> to 10mhz, but it's difficult to hear the fine structure of the
> modulation with only the am detector that is available; that is,
> everything just sounds like line noise. In essence, I'm not sure if  
> I'm
> listening to my interference or general line noise of which there is a
> goodly amount.
> I can null the line noise out with my mfj noise canceller or I can  
> null
> out the offending noise spikes, but not at the same settings, so there
> are two different noise sources methinks.
> Thanks for any ideas of what the train of spikes might be!
> Jerome - VA7VV Vancouver
> p.s. if you have trouble with the wav files, try playing them with
> QickTime.
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