Broadband does interfere
In a recent letter, Tony Whelan, CEO of an Internet service provider, makes the claim that his "very live roll-out" of broadband-over-powerline (BPL) Internet does not interfere [September 2: " This broadband doesn't interfere].
He cites several examples of critical radio services which have not experienced harmful interference from his BPL system. But there is more to the picture than the vignette Whelan paints.
None of his stated examples use the medium or high frequencies which are most susceptible to harmful interference from BPL. His examples are all members of the Aviation and Land Mobile radio services which use the much quieter VHF and UHF frequencies. BPL interference is 10 to 100 times as intense on the lower frequencies used by AM broadcast stations, and short wave frequencies used by military, government, airline, maritime, and amateur radio services– many of which are crucial to life and limb!
An added problem with BPL is that it not only affects the neighborhood where the wires are located, but those same wires act as giant antennas to radiate their errant signals over theÊlong distances that the MF and HF radio waves can propagate. This means that the Manassas BPL system could potentially interfere with an airliner over the Atlantic Ocean trying to make vital contact with the New York Air Traffic Control Center.
I suggest the power utilities stick to delivering 60-Hertz electrical power and allow the cable and telephone utilities to deliver the radio-frequencies they are so much better equipped to deliver in a professional, responsible manner.
FCC Licensed Consulting Radio Engineer