[RFI] 30m noise problem

jerome schatten romers at shaw.ca
Thu Apr 22 08:07:07 PDT 2010

Hi Dale et al -- and thanks for your responses!

As I told k8fc who responded privately, new data shows that twice in one
week, the noise disappeared completely at some time between 2200-2300
hrs. I just may not have been staying around to operate past that time,
'assuming' that the noise persists through the night. It's certainly
there when I rise around 0630-0700. I will further try and pinpoint the
on/off times and correlate that with other observations.

The touch lamp; a TV; other things which get turned off at bedtime now
seem more likely. 

A whole new ball game where a full coffee pot and more targeted
observations may yield a solution!

Being aware of the folly of 'Induction on one piece of data', I remain
ever optimistic!

Jerome - VA7VV

On Thu, 2010-04-22 at 05:17 -0500, dalej wrote:
> 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
> 73
> 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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