QUOTE: Brad: There is something on that website that my browser doesn't like - probably a badly-written JavaScript.

Yes, Opera browser also has trouble with it. It is running some ad-service script that calls up a whole slew of advertising monitoriing sites every few seconds. In my case, that prevented the browser "back" button working, and I could only get off the site by closing the tab.

Opera (European origin) is strict with open standards for Javascript. The American browser developers, including Firefox, are more willing to compromise and include non-standard tweaks to suit the interests of the advertising community (who basically own the browser economy now).

Maven

With three teenagers and two grandchildren all living at home it's not very often I get a chance to wander around turning things off but today for the first time in ages I'm home alone!

After wandering around with a small AM radio with earphones investigating the whole house, I've discovered my 18 year old son's bedroom is an evil den of RFI after nearly having my eardrums blown out. A process of elimination showed that his multi media power board is the culprit. It's one of those ones with surge protection and USB outlets. The worst part of it seems to be the USB charger, with nothing plugged in it's just noisy but as soon as something's plugged in it acts as an aerial and amplifies the noise. The power board gets progressively worse as more items are plugged in. This noise has been driving me mad trying to track it down. It started intermittently 12-18 months ago but has been getting progressively worse until now it's constant. In hindsight this is because he's been 'resting' in his boy cave (a place I seldom dare venture) since finishing his HSC. Unfortunately my workshop is right under his room, the RFI can be picked up from over 10m away.

I'm not going to investigate why it's so noisy, just smash it to pieces and buy him a UPS. Nothing else in the house was noisy except at very close range, UPS's, CFL's, wireless network, fridges, air con etc. were all okay. The electronically controlled washing machine made a bit of racket on the spin cycle but I can live with that.

A process of elimination showed that his multi media power board is the culprit. It's one of those ones with surge protection and USB outlets. The worst part of it seems to be the USB charger, with nothing plugged in it's just noisy but as soon as something's plugged in it acts as an aerial and amplifies the noise.

Good job. Thanks for the heads-up. Will file that one away in the memory bank -- what's left of it.

I have noticed that the circular fluros in my display room radiate crap. The normal fluros in the rest of the shed don't. They are the ínstant on' type as well.

Circular fluoros have the same technical makeup as the straight ones and apart from the power rating they are compatible with the three main types of control gear.

Your problem will relate to what types of control gear are in place in each type of fitting rather than the type of tubes.

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A valve a day keeps the transistor away...

Good work, Scraps! Bizarre that something calling itself a "multi-media" power board would ignore EMI in its design, but probably common now.

I'm afraid my workshop might be nearly as evil as your son's bedroom, in RFI terms. I've got two fluoros, at least one PC PSU running most of the time, and about six plugpacks supporting wifi, router, PC speakers, rechargeable tools, and even my "Trannymitter" (AM transmitter in a tranny case). I'll follow your example with a baby receiver to try and track down if any one of those sources is particularly bad, but I'm afraid they may all just be adding a small bit, not to mention neighbours' massive solar-power inverters and whatever is going on in the kitchen upstairs.

With plugpacks and PSUs, it seems often to be the earth or shield connection that becomes the amplifying antenna for RFI. I've had a whole computer case light up RFI-wise when I connected an external hard drive with a cheap PSU to the USB.

Maven

There are traps with regulated power supplies, I have made several and what I find and it it obvious that a commercial manufacturer in the next town has found also.

If either polarity of the output side of the PSU, manages to come in contact with any form of direct earth. (eg mains plug, or a water pipe) They loose regulation & go crazy.

A battery radio that requires a grounding for its antenna and the primary of the antenna coil is not isolated from the chassis, when used with such a PSU has to be grounded via a 0.01 mfd HV cap.

The local commercial unit carries that note and earths via a cap.

Marc

There's a short article on the subject of RFI from LED lamps in the current issue of Radio Waves. It makes reference to this interesting video showing various LED lamps being tested for noise:

http://www.youtube.com/watch?v=o8zMhjXcmoA.

Interesting video. Even without all the elaborate test setup, the different levels of EMI were plainly audible on the soundtrack of the video itself. It wasn't clear to me whether he was running an audio output from his test receiver, or whether the EMI was being picked up by the camera's microphone cable. A compulsory EMI label rating would be a good thing for these products, so buyers can make informed choices.

Maven

It wasn't clear to me whether he was running an audio output from his test receiver, or whether the EMI was being picked up by the camera's microphone cable.

I expect we were hearing the audio output of the Perseus radio, which he was using as a psuedo spectrum analyser to get the figures needed to compare to the applicable RFI conductance standard.

Given the self-certification that now exists, if the relevant authorities were doing their jobs, then any product that can be shown by a responsible person to fail the standard ought to be withdrawn from sale by mandatory order. But of course the authorities don't give the proverbial rat's. Hence his call to hams to take up the battle against RFI or lose their hobby.

I've just discovered another source of intermittent RFI that's been driving me crazy for weeks, in hindsight since the cold weather set in. It's a constant tick tick tick at about 2 Hz which at first I thought sounded like a faulty cap or valve in a radio I'd just finished recapping and was testing as that's the first time I'd heard it. I spent days trying to find the fault occasionally thinking I'd fixed until it came back again. I then discovered it was coming through on other radios (a lesson to be learned here!). Using my little portable radio again I wasn't surprised to find it coming from my son's room. It turned out to be his Sunbeam electric blanket. I can understand cheap and nasty appliances not complying, you get what you pay for but it's annoying that supposedly reputable companies still put this crap on the market.

Methinks you need to build a Faraday cage around your son's room.

"Though in saying that, who is policing communications laws in Australia these days? The police aren't because it falls outside their jurisdiction. Are there any DOC inspectors like there were 20 years ago? Not that I know of."
There was a Brisbane based compliance inspector employed only last month (ACMA).
I have heard from an ex-compliance inspector that there hasn't been a proper one for some time at least for SE Qld.
They can audit licensed installations, amateur and commercial, and ACMA are the authority who deal
with noise, illegal operation, etc. Don't know if they look into appliances and the like though. I haven't heard of that one.

What are people doing to prevent killing themselves with electricity these days?
I have a variac, isolation former made of two transformers back to back.
It occurs to be from what I've been told that use of either an isolation former or RCD would depend on what you think might happen to you.
ie. if you grabbed both sides of an isolation former secondary, the RCD won't detect any imbalance,
but if you grab any one side of the former secondary, it is no longer referenced to the earth beneath you, and you don't rely on the speed or operation of a physical mechanism.

ps. my experience with the Jaycar variac is good so far, and I'll possibly get a second one. I'm using it to power any valve appliance all of the time, You can wind up the filaments slowly, and all radios and amps I've tried will run much lower than our mains voltage.