[AMRadio] Radio Noise, BPL?


doxemf at aol.com doxemf at aol.com
Tue Jul 15 02:39:20 EDT 2008


Jim,
I went around inside the 4 story building and a bit outside using a 
Radio Shack DX-390 but the RF gain control doesn't work for MW or LW 
where the ferrite antenna is functional so only marginal D.F. ing was 
done due to front end overload. But the noise does appear to be power 
line radiated and from other places besides the Panel previously 
mentioned.

The signal is so strong at 1230 that mixes heavily with the local 1KW 
AM station at that Frq.

One thing that I could confirm is the perfect 10 KC spacing of the 
harmonics? starting about the middle of the BC band and fairly 
consistent in level right on up with a gradual drop in level to at 
least 8 mhz. every 10kc. The strongest levels are in the B' cast band 
but that might just be characteristic of the receiver since it switches 
to the whip antenna above 1700kc. It is not really noticeable at 10 
mhz. alongside WWV.

The signal looks like a square wave and gives very little zero beat 
with the BFO engaged.

I won't contact the Electric company until I am sure where the source 
is.

Will use the old solid state Tandberg portable on Tuesday since the 
ferrite antenna is functional up to about 5 mhz
and the off axis nulls are real good. The DX-390 has weak nulling and 
broad lobes.

Have got to get the Spectrum Analyzer running. Have yet to determine 
the fundamental frq. or even if there is one.

It was real strong this evening/night making it near impossible to even 
hear the strongest stations on 3885. due to the 3880/90 noise peak 
being in both the lower and upper pass band edge.

I will find out where this is coming from and put a stop to it somehow 
!!

It is certainly strong enough to exceed the FCC spec for spurious 
emissions and could be considered as interfering with licensed services.

73,
 Bill KB3DKS


-----Original Message-----
From: Jim Miller WB5OXQ in Waco <wb5oxq at grandecom.net>
To: Discussion of AM Radio in the Amateur Service 
<amradio at mailman.qth.net>
Sent: Tues, 15 Jul 2008 12:16 am
Subject: Re: [AMRadio] Radio Noise, BPL?

That is indeed strange.  I can think of wireless intercoms, wireless 
light
controls etc that use the ac line for their carrier usually at low
frequencies I believe.  I really cannot think of anything else right 
now.





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