Be Excellent To Each Other

Nerdy anorak people have long complained that powerline network adaptors killed their reception of Short Wave and the amateur radio bands. But nobody really cared about this as these people smell and have no friends. Ofcom certainly couldn't give a toss.

However there is a new generation of powerline adaptors out. High speed adaptors that promise up to 1 gig (so probably 20 meg at best then). However these adaptors have been found to interfere with FM and DAB services.



Lets hope these get withdrawn from the market sharpish or broadcast radio reception will be ruined for many people.

My god, that's an awkward presentation. Interesting data though. Has anyone measured the range of the generated interference? Presumably it varies greatly with the layout of the mains wiring in your house, as it's effectively using that as an antenna.

What I don't like about this is that instead of these devices being illegal, all they do is try and resolve the issue when there is a complaint. These things shouldn't be allowed to be sold in a state where they generate interference.

Those of us with long memories will remember that in the early 1990's the EEC introduced new emissions standards for electronic equipment to stop devices emitting interfering. The spec documents for the CPC Plus machines written by the designers at Amstrad specifically mention that the machines had to meet the new standards. Sam Coupe fans will also remember that whatever company owned the Couple that particular week hit a load of problems as the Coupe didn't comply.

But yet Belkin and their ilk are allowed to sell this crap. And the reason the radio amateurs have complained is because they are at least technically savvy enough to understand what is going on. The current adaptors pretty much kill all AM radio nearby, the new ones will also kill FM and DAB. But Joe Public isn't really savvy enough to know why their reception has gone to crap. With DAB its bloody hard to trace the source of the interference as well.

Of course Spec chums will well remember that all Speccies are quite capable of kicking out quite a little field of interference. In fact (from memory) if you tune your FM radio to about 97.3 you will hear whatever sounds the Speccy is playing. Goes for a good 10 metres.

One thing I noted about the presentation. The radio is right up against the wall. Hmmmmm.

I'm concerned about axe-grinders. If you google words like "powerline" and "interference" you get loads and loads of comments left on product pages on ecommerce vendors complaining about it... but they are word for word identical. That's not many OFCOM complaints either. And I've dealt with OFCOM professionally; they're pretty good at their jobs.

I'd test it myself but I don't own a radio and my Comtrend powerline kit is the lower speed 200meg stuff.

His son's got a telesync pirate of Transformers 2. Someone should shop him!

There are certainly some people with some axes to grind. But I've also been on some of the radio forums where people are complaining their reception of AM stations has been degraded. Most have just shrugged their shoulders and gone and bought DAB sets for the house. I've certainly driven past places where the reception of Radio 5 makes a noise not unlike what you heard on that clip. It's only fleeting as you are moving and I can't be sure its powerline adaptors but it is the kind of interference that has only cropped up in the past few years.

Since the government is wanting to switch off FM anyway, I'm sure they'll be all for anything which degrade the quality and cause inconvenience for users. DAB is bound to be less susceptible due to the error rejection.

A) FM ain't gonna be switched off any time soon. There is no route to DAB for smaller stations or community stations so the plan will pretty much be to let the larger stations go to DAB only leaving the smaller services on FM.

B) You didn't watch the video did you? DAB gets killed as well. Totally.

C) The error correction on DAB is shit. It really isn't as robust as its made out to be.

Given the plugs are hardly designed to be long range transmitters, I'm not convinced that even widespread use of plugs would have nuch of an effect on aviation radio unless some goon decides to put a plug in the control tower or something.

Could be wrong.

This is very true; stand in the way of the aerial and the sound distorts like it was recorded underwater. The sound quality isn't great either, it's like a relatively low bit rate sound file. Not that most people would notice, admittedly, as a lot of domestic all-in-one DAB sets only have tiny crap speakers.

I didn't watch the video, I'll happily concede DAB is shit though.

Also, if these things cause that much interference then they're probably not CE EMC compliant, so you can get the actual products withdrawn if proven.

Ok, watched the video now. Poor.

Not convinced that these things intentionally operate in broadcast and comms bands, just can't see how that would be allowable.

They need bandwidth from somewhere. The idea is that they are supposed to be using those frequencies on a closed loop system (i.e the mains cable). That is allowed. Indeed the UHF out on your VCR works on such a closed loop system. There are quite a few instances of VCR/AV modulators going faulty and starting to transmit. There was a guy on Danny Baker last year who for years got to watch the football for free as there was something wrong with the Sky box of one of his neighbours. His free feed ended when he noticed one of the houses nearby having an upgrade to Sky Digital. Presumably the digibox had been squirting a signal back up the TV aerial and broadcasting it at very low power.

The problem is that in a lab they probably don't interfere, but due to the way houses are wired I guess it can happen. Also mains wires aren't screened. The great unknown is the house wiring and there is no standard setup.

Lab testing is one thing. Oddly enough I'm sitting here at the moment editing some lab tests. I can't talk about what we were doing but there was a bloody good example in there of why lab testing is totally different from real world testing.

I like it. It managed to turn that awful dentist music into something that sounds like an 80's Atari game.

I'd say that's totally different: in the case of a UHF modulator the RF signal is carried along a proper RF co-axial cable, which is specifically designed to prevent it from radiating the signal out along its length.

Mains cable isn't! It's an unshielded, un-twisted pair - it's a bloody aerial! [edit: as you said later]



This is quite common, it happens when people put a splitter on the back of the TV and then plug the digibox (or VCR or whatever) *and* the external aerial into it, instead of connecting the aerial to the back of the VCR as you're meant to.



Well if these things have gone through any EMC chamber I guarantee they weren't transferring data when the test was being run. This is a common dodge and it means the test certificate isn't valid, so they're breaking the law by selling them. It'd need someone to complain about it through the proper channels though.

I'd say that's totally different: in the case of a UHF modulator the RF signal is carried along a proper RF co-axial cable, which is specifically designed to prevent it from radiating the signal out along its length.

Mains cable isn't! It's an unshielded, un-twisted pair - it's a bloody aerial! [edit: as you said later]



This is quite common, it happens when people put a splitter on the back of the TV and then plug the digibox (or VCR or whatever) *and* the external aerial into it, instead of connecting the aerial to the back of the VCR as you're meant to.



Well if these things have gone through any EMC chamber I guarantee they weren't transferring data when the test was being run. This is a common dodge and it means the test certificate isn't valid, so they're breaking the law by selling them. It'd need someone to complain about it through the proper channels though.