RF Measurement on 120V Circuits

[TigerWebb30]

Does anyone have a circuit for measuring rf levels on a standard 120V circuit with a spectrum analyzer? I would like to plug directly into an outlet and feed the signal directly into my spectrum analyzer. Obviously the 120 volts is a problem. Is there a device or circuit out there that allows the rf signals to be pulled off of the 120V circuit and fed into a spectrum analyzer via a coax cable? The frequencies of interest are from 1Mhz to 40Mhz. Thanks in advance for any help.

 

[RadioRon]

Does anyone have a circuit for measuring rf levels on a standard 120V circuit with a spectrum analyzer? I would like to plug directly into an outlet and feed the signal directly into my spectrum analyzer. Obviously the 120 volts is a problem. Is there a device or circuit out there that allows the rf signals to be pulled off of the 120V circuit and fed into a spectrum analyzer via a coax cable? The frequencies of interest are from 1Mhz to 40Mhz. Thanks in advance for any help.

What you are looking for is called an LISN:

LISN - Wikipedia, the free encyclopedia

You can build your own.
Here is a schematic:
The Electrical Engineering Handbook - Google Book Search

or here;
https://www.electro-tech-online.com/custompdfs/2009/01/3810-2.pdf

You must use good RF construction practice by keeping lead lengths short. Obviously you want to be careful to spec the parts to that the line voltage doesn't blow through and burn your analyzer.

**broken link removed**

**broken link removed**

https://www.ets-lindgren.com/pdf/LisnElec.pdf