Re: signal leads that pick up less ambient noise?

"piglet" <erichpwagner@hotmail.com> wrote in message news:vp9uol$3diav$1@dont-email.me...

Christopher Howard <christopher@librehacker.com> wrote:

Frequency??

>
I'm not sure exactly, but when I zoom in to it on the scope, the noise
appeared to have a regular ebb and flow of about 40 Khz.
>

>
That seems very likely to be from some power supply, either wall wart or
built into some equipment.
>
A great EMI sniffer to sleuth out is an old school $5 pocket AM broadcast
radio (the kind slightly larger than a cigarette pack and powered by 2 AA
or 9v block battery).

Ah yes thanks for reminding me. I've used that method many times.
Waving a problem detector around and then demonstrating that it goes silent when you put it in a closed metal box can be an
excellent way of demonstrating that a metal box may be needed in some cases.
You don't even need to read any text books by anyone at all.

>
--
piglet