EEVblog Electronics Community Forum

Electronics => Projects, Designs, and Technical Stuff => Topic started by: westfw on March 20, 2018, 08:51:58 am

Title: Hobbyist project emissions testing...
Post by: westfw on March 20, 2018, 08:51:58 am
Suppose I am a hobbyist with some basic test equipment (an oscilloscope) and parts, and I'd like to do some basically qualitative or comparison of RF emissions of home-built projects.   Nothing that would pass for actual product testing, of course, but ... something that would allow you to look at a PCB vs a breadboard, or "look at how emissions go up if I attach a 6inch wire to the micro's crystal oscillator output!", or (perhaps most importantly?)  "this is terrible" vs "this doesn't look too bad."

I guess it'd essentially be a sort of broad-spectrum radio receiver with a "received power" indication?

Is that possible?  Reasonable to construct from ordinary parts?  I don't really care about specific frequencies (I don't think.)  Just sort of overall "leakiness"...
Title: Re: Hobbyist project emissions testing...
Post by: fourtytwo42 on March 20, 2018, 09:59:48 am
What about using a laptop SDR with external antenna,that way you get to see amplitude and frequency and can make whatever probe suits your needs
Title: Re: Hobbyist project emissions testing...
Post by: mmagin on March 20, 2018, 11:49:59 pm
I use a cheap USB SA, an eBay calibrated RF generator and a microwave oven to do pre-testing.

A microwave oven is not an effective Faraday cage, except at 2.4 GHz due to how it relies upon the geometry of the door flange being a quarter-wave trap.  You'd be better off taking a metal toolbox or filing cabinet and adding some sort of conductive gasketing / contacts to the openings.