[Top] [All Lists]

[RFI] Terrible RFI

To: <rfi@contesting.com>
Subject: [RFI] Terrible RFI
From: michael.findley at ni.com (michael.findley@ni.com)
Date: Thu Mar 27 07:50:18 2003
Sounds like a dirty insulator on  the main power lines. When it gets dry
the dirt creates a corona type effect and after a rain the noise should get
allot quieter. Seems like this is what you are describing. Does this help
(Embedded image moved to file: pic26777.gif)

                      "Bob Thacker"                                             
                      <k3gt@pgh.net>           To:       <rfi@contesting.com>   
                      Sent by:                 cc:                              
                      rfi-bounces@conte        Subject:  [RFI] Terrible RFI     
                      03/26/03 07:52 PM                                         

Hi All,

Have had a terrible time finding interference sources and been battling the
power company for over seven, yes, seven years. But, that is a whole story
in itself. Right now I am at wits end trying to locate the source.

Here's the problem. S7-9 Noise Level (worse when it is drier) on 10 & 12
meters with other bands being affected depending on how dry the weather is.
160 meters is S 7 at night. A sweep of 1710 KHz AM broad cast band
peaks on the power line at what appears to be irregular intervals over a 1
mile stretch.. An MFJ Noise meter indicates one small source about 3/4 mile
away. However, I do not feel this is the source. As night falls, the noise
lessens a bit to where I see 2 peaks from the radio station indicating the
same direction as the peaks on the power line. An interesting phenomena
occurs on 1020 KHz, KDKA's 50 KW station which is about 3 miles away, the
noise totally obliterates the signal at one of the noise peaks on the power

The power company is blaming neon signs from a small strip mall located at
further distance from peaks on the power line. A sweep with the MFJ box
indicates that indeed these signs are very noisy. After a polite discussion
tonight with the noisiest sign owner, we turned off 3 signs. There was no
change on the receiver noise at home, which the XYL was monitoring. There
are 2 more signs to check, 1 is the marque sign which will require more
effort to locate the strip mall owner and another store where I know the
owner. However, the owners have turned these signs off in the past, which
did not correct the problem. Going to double check to be sure.

A sweep of the local 1 -2 mile area with the MFJ box indicates no local
noise generating from the usual troublesome door bell and touch lamps.

I have the ARRL RFI book and tried their suggestions but coming up blank.
there any way to tell from the sound of the noise as to what it may be
coming from? It sounds more like a buzz than a crackle, if that makes
Talk about being at wits end! Any suggestions would be greatly appreciated.

Thanks to all.



RFI mailing list

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