[RFI] Oscilloscope requirements for power line noise locating

N1BUG paul at n1bug.com
Mon Dec 31 09:20:05 EST 2012

Thanks Cortland.

The terminology they use is somewhat different than what most of us 
would use. What they call a field strength meter in the CATV 
industry is actually a frequency selective voltmeter - a basic 
tunable receiver. Those meters have a video output intended to drive 
a scope, which many have used to see power line noise signatures. 
But exactly what is output on that port I honestly don't know. I may 
have to buy one and look at what comes out of that port on my 100 
MHz scope in the shop to figure it out. It's probably supposed to be 
obvious, but... not to me.

Paul Kelley, N1BUG
RFI Committee chair,
Piscataquis Amateur Radio Club

On 12/30/2012 12:35 PM, Cortland Richmond wrote:
> Paul,
> Even an audio scope is good enough if you first rectify the RF to
> recover the envelope. I presume that's what they were talking about WRT
> the Sadelco (etc.) FS meter.  These old CB meters' sensitivity increases
> with frequency (until the sampling baod nears resonance, anyway) but you
> can use a toroidal style meter to get a pretty level response.
> For DIY directional couplers, check out (for example)
> http://www.hoaglun.com/blog/2010/1/16/directional-coupler-version-two.html
> Cortland
> KA5S

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