What does PLT sound like?

Headphones and Signal TraceThis page contains some “sound bites” of past and current PLT systems, as an aid to identification of interference sources.

Most data-over-mains devices are “notched” so that they do not cause high levels of emissions on amateur bands. However, elsewhere in the shortwave spectrum there remains the possibility of interference.

Interference outside notched frequencies

PLT Data Transfer one device

Comtrend Powerline adaptors (shipped as part of the BT Vision package)

Two types of access PLT recorded at Crieff during the trial in November 2002

A) The Mainnet system

Recorded about 3m from the house on the 7MHz amateur band. This is described as a spread spectrum system. Interference depends on the density of traffic. Recording starts with light traffic increasing as the recording proceeds.

Listen (WAV file, 63Kb)

B) The Ascom system

Recorded about 4m from the house in one of the “delivery” frequency bands. This system uses three discrete frequency bands, below 10MHz, to deliver signals to the house. The bands are about 1MHz wide.

Listen (WAV file, 84Kb)

C) The Ascom system

Recorded about 4m from the house in one of the “in-house” frequency bands. This system uses three discrete frequency bands above 10MHz to distribute signals in the house.

Listen (WAV file, 84Kb)