[RFI] Do we neglect problems and fix symptoms?

[Charlie Gallo]

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)