If you are planning on buying homeplugs - consider this first.
 

Hi all, homeplugs may well be one of the best things since sliced bread to some, but to radio users they are the devils spawn. :mad:

They can cause widespread interference in the radio spectrum and are amongst the reasons why many radio amateurs cannot use their licensed equipment at home. I am amongst those that cannot as I get so much noise that I cannot hear people who I could hear clearly if I was away from the house (it's not mine - its the neighbours).

Anyway - whats likely to be coming is further regulations that will make it illegal for end users to be causing interfierance - so the best way of preventing this if you do have to buy those awful doohickeys is to buy good quality\decent brand name ones rather than cheap unknowns that have likely never been through EMC testing. :)

http://stakeholders.ofcom.org.uk/bin...n_Document.pdf
http://stakeholders.ofcom.org.uk/con...einterference/

The same may well apply to Plasma TV's, central heating equipment etc.

Re: If you are planning on buying homeplugs - consider this first.
 

RF interference was a major bugbear when I worked at the Home Office Directorate of Telecommunications. Everything from microwave ovens to heavy factory machinery would be detected and shut down if they were transmitting excess RFI. But these days there just doesn't seem to be the budget or manpower to police the airwaves.

Re: If you are planning on buying homeplugs - consider this first.
 

Thanks for the heads up. I shall endeavour to find a way to ensure the composite products of some horrendous Chinese homeplugs wipe out everything on the airwaves below 90MHz ;)

What are the actual frequencies that these devices are supposed to be avoiding?

Re: If you are planning on buying homeplugs - consider this first.
 

All of them :)

Re: If you are planning on buying homeplugs - consider this first.
 

It' hittng the news more now

http://www.telegraph.co.uk/finance/n...s-to-GCHQ.html

http://www.telegraph.co.uk/technolog...-networks.html

Re: If you are planning on buying homeplugs - consider this first.
 

Prosecutions for that are likely to be as common as those for recording a phone call without the other person's permission and opening mail intended for someone else.

Re: If you are planning on buying homeplugs - consider this first.
 

No, but Ofcom have the rights to confiscate equipment especially those cheap systems sold on eBay which have not been built up to a standard required for import.

I'm lucky in that there seems to be none in this area causing me problems

Re: If you are planning on buying homeplugs - consider this first.
 

Could spell the doom for DAB radio. :) A bit of hash on FM could mean complete failure of the digital signal.

Even if these things sport a "CE" symbol*, I doubt many have been fully tested for compliance and as there is no control over the way they can be deployed and the wiring that they are plugged into, spurious emissions are a certainty.


*The CE symbol means the product has been rigorously tested for its possibility of interfering with other equipment and also its immunity from incoming interference. Applying a CE mark to non-complying equipment is an offence as is selling non-compliant equipment. Part of the work I do is the testing electronic equipment for compliance and writing up the reports, it's very onerous, detailed and expensive to do and requires much technical equipment and a special shielded room.

Re: If you are planning on buying homeplugs - consider this first.
 

They also have the right to confiscate equipment from someone broadcasting on SSB on their Cobra 148 through a 500w burner but we know often that happens despite people still doing it these days ;)

I can't see many people falling foul of the use of homeplugs. There might be the odd token prosecution just to get people thinking about it but I'd say it's unlikely to be more than that.

Re: If you are planning on buying homeplugs - consider this first.
 

There's been a few home visits and confiscations reported on the radio forums recently. Ofcom though very rarely patrol the bands but they still do react on interference reports especially from licenced users (broadcast and amateur). You have to remember that 500w ssb even if overdriven is more than likely to just splatter on the same band where a cheap plt will block out signals across a large swathe of bands even at minimal power.

Another side of it is if the equipment being interfered with is up to standard and filtered itself.

Re: If you are planning on buying homeplugs - consider this first.
 

Indeed. If OFCOM couldn't be bothered to even look at my illegally modified wireless equipment emitting over 3000x the legal power limit across several square kilometres of a capital city I doubt they're going to bother chasing after homeplugs.

Re: If you are planning on buying homeplugs - consider this first.
 

Which at that freq is going to attenuate through buildings really fast.. even at 300w.

Lets see you transmit a few miles through a built up area compared to how far you'd get on a sub 30Mhz signal with a standard antenna. With a few milliwatts people have transmitted over thousands of miles (current QRP record is 1650 miles @ 30Mhz on 1microwatt)

That's the crux here, ofcom don't care about single cases or signals that don't effect many users. Where as a PLT can effect many users with a cumulative effect in inner city areas where lots of these devices can be in one area

Re: If you are planning on buying homeplugs - consider this first.
 

It's already transmitting a few miles through a built up area, like I stated above. Sure, you can get further with lower frequencies but powerline networks aren't connected to rooftop antennas deliberately designed to spread the signal as far as possible, they're hooked up to underground cables deliberately designed to not spread EMI.

It's affected enough for at least three different companies to complain ;)

Re: If you are planning on buying homeplugs - consider this first.
 

Problem with PLT's and thier wiring is that most of the house wiring is varying lengths strung up between floors and even near roof height. Put in a small spurious signal into that lot then most of the time it'll find a resonant wire and will interfere with licensed services to those local. Cluster in a few complaints and that's when Ofcom will jump especially if broadcasting/communication services are those effected


:redcard: Yet the average home user will just think it's their BB equipment acting up if at all it effects them due to the proximity of thier own equipment. You work out the db from your signals compared with the signal from/to their own equipment and unless they are direct line of sight without obstacles it's gonna do nothing to them except perhaps make them choose another channel.

Re: If you are planning on buying homeplugs - consider this first.
 

Possibly. To be fair I don't know what actual frequencies powerline networking equipment uses, Wikipedia suggests something in the two-digit Mhz range. With that in mind, ADSL and Ethernet both use unshielded cabling and frequencies of 0-17, 30, or 100Mhz at incredible densities over large distances including overhead wiring, so how much of a problem can it really be? Sure, AC mains wiring isn't twisted pair, but again, the signal doesn't go much further outside the house whereas xDSL does.