Our story this month about trials of Broadband over Power Lines (BPL) should give everyone cause for concern. While low-cost universal broadband internet access is a desirable facility for virtually everyone these days, it should not come at the cost of conventional radio services.

Just imagine every street in every major city and town in Australia blanketed with BPL signals ranging from just above the AM broadcast band to just below the FM band – almost 80MHz of bandwidth. This will play merry hell with all the radio (and TV) services in that range. In fact, it would mean the end of any useful radio services in that range. You can forget any 27MHz CB radio, radio control, all shortwave radio, emergency services, amateur radio, business radio, analog cordless phones and virtually anything else which might be in that 80MHz bandspread.

So why have trials been authorised, both here and overseas? Good question. The answer must be that the relevant energy authorities have lobbied very hard to be able to use their vast wire grids for something else besides just carrying electricity.

Even so, it is incredible that the trials have even started, let alone be permitted in the first place. It makes a huge mockery of all the EMC compliance regulations that all electronic equipment must now meet. Why have EMC compliance when the power authorities will be able to blast interference out to everyone, completely unfettered by past regulations? It just beggars the imagination!

I must sheepishly admit that when BPL was first mooted several years ago, I wondered how they would do it. I idly thought that they would probably send the signals via optical fibres down the inside of the power cables. After all, existing high voltage transmission lines use a steel core with an aluminium sheath – the steel core provides the tensile strength while the aluminium provides the conductivity. So it would not be a huge step to put optical fibres inside power cables.

It just did not occur to me that BPL would involve feeding the signal directly onto power wires – after all, that would radiate like crazy, wouldn’t it? Well, silly me. There never was any intention of modifying all the power cables to take optical fibres. How naive of me! I just did not think it through.

And the people who authorised BPL trials have not thought it through either. BPL in its present form is a very bad idea. It might initially appeal to the non-technical populace but when the true ramifications take hold, there will be hell to pay!

Leo Simpson