September 19th, 2005 at 10:50am
Broadband Over Powerline (BPL) is an exciting new technology that utilises the existing powerlines to bring broadband Internet access to every home with a connection to the elctricity grid. BPL is really just a new adaption of existing Power Line Communication technology used in such things as home automation.
The alternating current that currently uses the power lines operates at 50-60 Hz depending on your location, whilst the newer BPL signals operate at around 1-30 MHz and can bring speeds of up to 2.7Mbit to homes. Whilst this is certainly a clever technology, it has certain issues.
Some people may have already worked this out simply from reading the above, but I’ll explain it anyway. Powerlines tend to be unshielded and untwisted, making them perfect antennas, and this also means that they are very good at creating radio frequency interference.
The main problem with BPL is the enourmous amount of interference that it does create, in some cases blocking out AM radio frequencies, as well as some amateur, government and defence frequencies. There have been reports of interference to the FM frequencies as well, although I find that slightly harder to believe.
Considering that virtually every suburban power line would be acting as a radio transmitter, the concerns of people in the radio industry (especially amatuer radio entusiasts) are quite understandable.
It’s not all bad news though, as the FCC and the ACMA (formerly known as the ABA) have released rules requiring “notching” of the frequencies used by BPL to avoid the interference. The majority of the BPL systems that are capable of notching frequencies operate at mainly higher frequencies and are therefore capable of higher speeds, it is expected that they will be able to provide speeds in excess of the 24Mbit potentially provided by ADSL2+
The important thing for now is making sure that the regulators are kept up to date on what interference is occuring, and to make sure that the electricity companies know that they can’t take shortcuts and create unacceptable interference.
BPL will be the way of the future, potentially providing much more than just Internet access, but it is important that it is setup in the correct manner, and the only way to ensure that is to keep a close eye on the regulators and the companies involved. I for one don’t want to lose AM radio, FM may be technologically superior, but I find AM has many benefits, including it’s incredible ability to “bounce” for incredibly long distances at night. People don’t seem to realise that AM radio is capable of stereo transmissions, or that digital radio will probably use frequencies currently used by AM radio. Certainly FM is better at reproducing music, but it is more suceptible to frequency drift.
I’m sure John B1_B5 understands the theory behind AM and FM better than I do and will hopefully be able to explain things a bit more clearly and correct any mistakes I may have made. I’ll admit that I don’t really understand the theory behind AM and FM radio very well, but I’ve done my best…
Anyway, I’m all for BPL, as long as it is implemented in a correct and cautious manner.