Path: ...!weretis.net!feeder9.news.weretis.net!usenet.blueworldhosting.com!diablo1.usenet.blueworldhosting.com!nnrp.usenet.blueworldhosting.com!.POSTED!not-for-mail From: "Edward Rawde" Newsgroups: sci.electronics.design Subject: Re: signal leads that pick up less ambient noise? Date: Fri, 21 Feb 2025 10:53:01 -0500 Organization: BWH Usenet Archive (https://usenet.blueworldhosting.com) Lines: 25 Message-ID: References: <87cyfd3hpz.fsf@librehacker.com> <87y0y1pksb.fsf@librehacker.com> Injection-Date: Fri, 21 Feb 2025 15:53:04 -0000 (UTC) Injection-Info: nnrp.usenet.blueworldhosting.com; logging-data="16172"; mail-complaints-to="usenet@blueworldhosting.com" Cancel-Lock: sha1:Qkg034myeMVVj69EH/DHoFVfkFw= sha256:LZ/r22VBGWUXQl1S+2hnEE7rKLFdmwDmJsss0dm3X/Q= sha1:DntgVDPCIx63isZevZpxPg78KSk= sha256:WO+m7UTnOK39WxwAYKnqLWd4vHqGcBqM/1U5yQ6+1Co= X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.6157 X-Newsreader: Microsoft Outlook Express 6.00.2900.5931 X-RFC2646: Format=Flowed; Original X-Priority: 3 X-MSMail-Priority: Normal Bytes: 2216 "piglet" wrote in message news:vp9uol$3diav$1@dont-email.me... > Christopher Howard 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