BPL: Broadband over Power Lines?

In the past, (many years ago), when I had more time, I have experimented with systems to transfer data and control signals around the home via the power wiring. In principle it is simple, just design and build an isolated transmitter which only has to feed your signals directly into the low impedance of the mains, and an isolator which separates the signal from the mains at the other end, much as your broadband filter does but at higher voltage!!! These can each then be plugged into your mains at any points in the house via the wall sockets.

Problems? How far does the signal travel? Who knows, maybe my neighbours would be able to pick it up, they weren't running the same experiments as me! There is no natural way to prevent anything you put on the mains going out beyond your house losing privacy and of course interfering with others systems. High frequency filtering could provide a barrier on the way out, much as I do as a hifi buff to clean the mains on the way in! There is another problem, it would certainly affect my audio listening if it were allowed at random. And the problem of interference from existing high frequency polluters of the mains signal like industrial switching and power equipment would mean random spurious effects.

An interesting idea but definitely not a new one. Maybe with fast data transfer systems becoming more and more common its time has come.

Whatever, if it becomes a reality, you can bet we'll pay through the nose for this "latest breakthrough" which can be implemented for a few pounds!

For those interested and possessing the foolhardiness of youth, (Servant ), remember the old adage, MAINS BITES! even if it is your puny little weak kneed lilly livered American 110V!

As you suggested in-house function control was the real aim in my day of course Paq. Switching on the TV from upstairs, ooer Dad, really? . High speed computer links were not needed! We are talking about 20-30kHz signals not 1Mhz, and digital? Digital Scmigital! Contrary to popular belief by the man in the street (know), many things are better left analogue! (Audio I would suggest ).

The isolating transformer principle is one way but is not the only one or even the best. Transformers being ostensibly magnetic current inducing devices, they need to have a current, albeit a small one, flowing through their primary coil to function. The idea of simply sensing around a live stub more like an aeriel and manipulating the signal offered by that leads to higher impedance working and hence suitability to more modern devices with better safety margins. Of course I had to make do with discrete transistors, remember them? Germanium? It could even be argued that the most suitable technology for this application would be valve! ("Toob" for the yanks!)

It will be interesting to see how they approach things nowadays with a different set of requirements and solution technologies. And what we will swallow about the costs of it all of course which will be astronomical as it is such a revolutionary idea! (Am I cynical or what? )

I can still do it nowadays for a few pounds!