[600MRG] Buying "NOS" line filters?

[Brian Pease]

Fine looking radio. I have a Channel Master AM radio with a real tuned 
RF input stage and large ferrite loop for this purpose that is really 
sensitive.


On 1/13/2025 3:12 PM, sbjohnston--- via 600MRG wrote:
> The most effective device I have for tracking MF noise is a vintage 
> transistor AM radio.  These old radios are available for a dollar or 
> two at garage sales, and for a few tens of dollars on eBay. Here's a 
> link to photos of my favorite noise-hunting radio: a Motorola 
> transistor radio from 1971.
>
> https://www.wd8das.net/AM-transistor-radio-for-noise-hunting.png
>
> It is completely portable and has an internal bidirectional loop 
> antenna.  You can couple the radio close to possible noise sources to 
> hear the sound of the interference and pinpoint the source.  And the 
> nulls off the ends of the radio are quite sharp so you can take 
> bearings and triangulate more distant sources.
>
> I tune the radio to an unused broadcast channel and listen to the 
> background noise.  I go toward the bottom of the AM band (550 kHz) 
> when I am interested in the noise bothering 630m and the other 
> services below the AM band, and tune toward the high end of the AM 
> band when I am interested in 160m or HF noise sources.  Usually very 
> helpful, and often the noise I am seeking is spewing all across the 
> band so tuning is not critical (other than to be tuned between active 
> broadcast stations on an open frequency).
>
> The horizontally-oriented design radios like this one often have a 
> longer ferrite loop antenna inside which makes for higher performance, 
> deeper nulls, etc.
>
> I describe using this radio to track noise in my presentation:
>
> http://www.wd8das.net/Tracking-Radio-Noise.pdf
>
>
> Steve WD8DAS
>
> sbjohnston at aol.com
> http://www.wd8das.net/
> http://af4k-crystals.com/
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> Radio is your best entertainment value.
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>
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