Sources of EMC problems
New Technology often introduces new RFI threats to the spectrum
This page summarises the topics currently under investigation by the EMC Committee and provides links to published reports on these topics
Broadband VDSL
- VDSL members Survey September 2017
- VDSL Drive by Measurements November 2017
- VDSL RFI RSGB:Ofcom meeting-June 21 2017
- vdsl-RSGB -final-report_on testing with Ofcom
- Ofcom spectrum-assurance-analysis-of-bt-openreach-vdsl
- October 2019 rsgb-meets-ofcom-to-discuss-vdsl-issues
- Presentation given at VDSL-RFI-Update-Ofcom-meeting-Oct-2019
- Response from Ofcom_ofcom_letter_to_rsgb_vdsl_meeting_oct_2019
Green Energy
- LED Lighting
- Solar Panels
- Wind Farms
Switched Mode Power Units (SMPU)
Plasma TV’s
Powerline Telecommunications – PLT
This 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)
- Interference to short-wave broadcast (first without interference then PLAs switched on) (WAV file, 308Kb)
- Two PLAs idling (no data being passed) (MP3 file, 518Kb)
- Two PLAs exchanging data (MP3 file, 491Kb)
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)
If you are having problems with other technologies please contact the EMCC.
