[RFI] Recent 40 Meter AC noises?

Scott Prather sdprat at att.net
Fri Aug 31 21:40:04 EDT 2012

Paul: I've observed this signal here in Seattle around the 40M WSPR
frequency (7038.6 kHz). The noise level on 40M is too high tonight to look
for it now, but I have seen this emission as recently as two weeks ago. It
consists of spikes at 120 Hz intervals as you've stated, and the level is
essentially constant. I've only seen this emission on 40M.


-----Original Message-----
From: RFI [mailto:rfi-bounces at contesting.com] On Behalf Of Paul K.
Sent: Thursday, August 30, 2012 9:35 AM
To: rfi at contesting.com
Subject: [RFI] Recent 40 Meter AC noises?

The past few weeks, not only me, but several folks I talk to around
7.260 in the mornings have complained about a "AC hum."  I have watched this
hum on the panadapter.  It appears to be spread evenly across the band, no
peaks or dips.  On the panadapter the spikes appear at about 120Hz interval,
about 3 to 6 dB above the noise.  I have rotated the beam and found the peak
level to be approximately 135 degrees.  It has been confirmed by a station
in western Missouri, central Indiana and Annapolis Maryland.  This noise has
been present nearly every morning for the past 2 weeks, but I did not hear
or see it today.

When this is on it does not sweep or pulse.  It is just simply present. 
I believe due to the wide spread reception of the exact same noise by
stations in vastly different areas the possibility of something locally to
any of us is highly remote.

So the curiosity is up.  What do you folks think we are hearing, and are any
of you hear other reports about it.


Paul K.

Paul K. WA0BAG
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