RFI
[Top] [All Lists]

[RFI] mystery noise

To: <rfi@contesting.com>
Subject: [RFI] mystery noise
From: k1ttt at arrl.net (David Robbins K1TTT)
Date: Mon Jul 14 07:27:47 2003
> 
> That one is sure different!  Haven't the slightest idea nor have ever
> heard
> anything like it.  Since it seems to be in the area of just a few
houses,
> does it vary with time of day or temperature?  If you hadn't said, I
would
> at first thought it to be a steam locomotive! :-)
> 
> Wonder what it looks like on a spectrum analyzer or on a 'scope?  

It doesn't seem to be affected by wx or time of day.  It does
occasionally seem to skip a beat or speed up or slow down for short
periods but not with any discernable pattern.

Sorry, no analyzer here.  I haven't put it on a scope, but from the
receiver sound I would assume it would look like noise.

> 
> And, thinking out loud, what does it sound like on FM?

Nothing, on fm I can't even hear the pulsing.  I can see it on the
s-meter but it doesn't demodulate to anything.

> 
> You just might drop a note to Mike, K3RFI, in case he doesn't see the
> post.

Who is k3rfi?  I had sent one to w1rfi a while ago but haven't heard
anything back.

> 
> Heaven forbid if this is what BPL would be like!
> 
> Please let everyone know what you find; never can tell when the info
might
> be needed.
> 
> GL & 73,
> 
> Tom - WA2BPE
> 
> David Robbins K1TTT wrote:
> 
> > i have been hearing a noise that i just can't identify, i have
narrowed
> > the source down to an area of 3 or 4 houses about 1/2 mile away from
my
> > station, but need to build a directional antenna to get it down
closer.
> > the real question is what might i be looking for????
> >
> > recording at: http://www.k1ttt.net/audio/rfi4125AM.wav
> > this recording was made at about the loudest peak i found at
4125khz, AM
> > mode, 6khz wide filter.  as you can hear it is a pulsing about 2 or
3
> > beats per second.  this noise repeats at irregular intervals from at
> > least 3410 to 4365 roughly every 30-60khz, in between the peaks
there is
> > virtually no trace of it.  the pulsing is not in sync on all the
peaks.
> > to me this sounds like a multiple carrier fdm power line modem, but
what
> > kind of device would be available that operates in this frequency
> > range??  does anyone know of a source of a noise like this??
> >


David Robbins K1TTT
e-mail: mailto:k1ttt@arrl.net
web: http://www.k1ttt.net
AR-Cluster node: 145.69MHz or telnet://dxc.k1ttt.net
 



<Prev in Thread] Current Thread [Next in Thread>