[Lowfer] Hz question.

[Clive S Carver]

Hi Kurt 

Being in the UK, I am not too familiar with the US distribution system. I'm
guessing, but assume that the 3-wire system is a neutral wire (which is at
ground potential) and two phase wires, each 120VAC with respect to the
neutral.

This single wire. Is it one of the two phase wires, or the neutral wire? Or
indeed is it a disused wire?

I would only expect to be able to couple using a torroid if this wire was in
use, thus giving a path for current at the frequency(s) of interest to
return via ground - your household equipment acting as a lowish impedance to
ground at that frequency(s). If the wire is unused, I see little point in
using a torroid since without current flow, the torroid would be acting as a
small capacitor (winding to winding capacitance).

I would be tempted to use a low value capacitor of say 1000 volt rating into
a battery powered buffer amplifier, with the output coupled via a torroid
isolating transformer into whatever you are using to monitor for signals.
The amplifier, torroid and battery all in an insulated box for safety.

Obviously you would need to satisfy yourself concerning safety aspects.

73's

Clive
GW4EYO

-----Original Message-----
From: lowfer-bounces at mailman.qth.net [mailto:lowfer-bounces at mailman.qth.net]
On Behalf Of KD7JYK DM09
Sent: 29 February 2012 22:50
To: Discussion of the Lowfer (US, European, &UK) and MedFer bands
Subject: [Lowfer] Hz question.

I have an idea, want to run part of it by the LF guys.

I have a single wire, part of a 3-wire 60 Hz 120VAC system.  I want to 
monitor any RFI there may be on the wire in a very simple fashion.  I figure

a could "sample" it by running the AC wire through a torroid, possibly a 
ferrite tube, possibly a binocular torroid, then wrap a few turns of a 
sampling wire through the torroid as well, then tap into this secondary for 
analysis.

Comments or suggestions?

Kurt

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