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Re: [RFI] Do we neglect problems and fix symptoms?

To: "Roger (K8RI)" <k8ri@rogerhalstead.com>, rfi@contesting.com
Subject: Re: [RFI] Do we neglect problems and fix symptoms?
From: Charlie Gallo <Charlie@TheGallos.com>
Reply-to: Charlie Gallo <Charlie@TheGallos.com>
Date: Fri, 31 Dec 2010 17:28:53 -0500
List-post: <rfi@contesting.com">mailto:rfi@contesting.com>
On 12/30/2010 Roger (K8RI) wrote:

> Routers or cable boxes are on the "return if a problem" list. Any new 
> piece of network hardware, router, modem, switch gets returned 
> immediately if there is a hint of a problem.

Definitely the way to go, if you can

Interestingly, my ROUTER doesn't cause a lot of problems - the MOTHERBOARDS do 
- Putting ferrites on the router end does almost nothing, put them on the PC 
side, and the noise goes away.  making a list of noisy MBs doesn't do too much 
good, as they seem to change every couple of months

The last fairly noisy item I had in the shack was an old CRT.

The most RFI prone item in the shack?  The original Microkeyer.  I know a FEW 
people who have problems with that box.  I understand (a little bird on this 
list with a reason to know told me) that the new version (Microkeyer II) has 
solved this problem, and I'm very, very tempted to replace the uKeyer, even 
thought I have killed MOST of the problem with the use of a LARGE amount of 
Ferrites (I can still trip it out if my 80m antenna is out of tune, and I hit 
it with 300 watts or more - then again, that antenna is only 20 ft or so above 
the shack)

The VFD on my milling machine does NOT seem to cause a problem, but then again, 
I've only been able to check with the mill running free spindle - but I really 
don't care - there is about zero chance the rig and the mill will be on at the 
same time (I can't be in two places at once, and if I'm cutting metal, I don't 
play radio - I use my brain for metal cutting then)

As for Mil-Spec emissions, I think I've said I was the "environmental Test 
Specialist" for a company that built power supplies/VFDs/UPSes among other 
'toys' - The company lumped RFI/EMC and acoustic noise in with 'environmental 
testing', as we'd often have both jobs bid at once, so that was something I got 
to play with.  You'd be shocked at how LOW a noise floor you can actually get 
on a SMPS, if you're willing to pay for it, and design for it. (Hint, look up 
the word TEMPEST  - and also think about how low an EM floor you want on a 
minesweeper, as there are mines out there designed to trigger on EM noise)  The 
basic RE/CE/RS/CS series of tests were only the beginning for some of this stuff

73 de KG2V - Charles Gallo
Quality Custom Machine-shop work for the radio amateur (sm)

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