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Re: [RFI] What I use to find Interference Sources

To: rfi@contesting.com
Subject: Re: [RFI] What I use to find Interference Sources
From: David Cole <dave@nk7z.net>
Reply-to: dave@nk7z.net
Date: Fri, 31 Jul 2015 04:20:14 -0700
List-post: <rfi@contesting.com">mailto:rfi@contesting.com>
You are so kind to send them, and I got them...  I will use your
suggestions in construction!  Thank you again sir!
Thanks and 73's,
For equipment, and software setups and reviews see:

For MixW support see;
For Dopplergram information see:
For MM-SSTV see:

On Fri, 2015-07-31 at 01:32 -0400, Ron Watson wrote:
> David, Frank may not have some pictures I have and will email to you.
> The RE units (238, 240A and 242 that I have) have digital filters in them 
> that come off the IF and gate at 120 Hz. then amplified and shaped for video 
> and audio, so the 60 Hz. components are well above any other source sounds or 
> frequencies.
> As seen in the pictures, you can make a pretty fair stab at similar results 
> just by hooking a common O-scope to the audio output of an AM receiver, Icom 
> 746 used in the pictures, also a comparison is the output of the Sprague 700 
> type units.
> On the O-scope you will need to trigger on the line frequency, I have done 
> fairly well by using a sine wave inverter in the car and triggering on it. A 
> sweep speed of 1 ms./div gets close to the same display as the RE units but I 
> prefer to sweep at 2 ms. (see pics). I also prefer to use a separate scope 
> when convenience is not a big factor, triggered scopes give a lot more stable 
> and defined view.
> Feel free to email me directly with any questions.
> Also attached a block diagram of an earlier RE unit.
> Ronald E Watson
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