Power Line Transmission – Friend or Foe?
Power-Line Transmission (PLT) is clearly an attractive proposition since there is no need to install new cabling; literally ‘plug and play networking’ for the consumer. It also provides assistance to the Government's 'Digital Britain' ambitions in getting broadband to everyone in the UK including those in more inaccessible areas. Currently there are around 750,000 PLT products estimated to be in use in the UK today. There is a catch!
In common with other electronic products sold in the UK, PLT products are required to comply with the Electromagnetic Compatibility Regulations 2006. These regulations are in place across the EU to regulate the levels of electromagnetic disturbance and to ensure that the electromagnetic disturbance interference generated does not exceed a level above which other equipment (including radio and telecoms equipment) cannot operate as intended. But the problem is that they do... PLT products have the potential to cause interference to the HF radio spectrum, sometimes described as "spectrum pollution". The power distribution network is not designed for the transmission of high frequency data services and as a consequence they lose much of the signal, radiating them as radio signals that can affect nearby HF users using those frequencies. So who is affected?
There are 65,000 Amateur Transmitting licences issued in the UK with an estimated 20,000 Radio Amateurs active within the HF bands that are open to interference from PLT products. There are also specialist HF spectrum users including the UK Coastguard, Defence and National Security. In addition there are Short-wave Listeners and other enthusiasts such as radio astronomers who may be affected. What are the implications for these users?
1. PLT products provide the equivalent interference of many other electrical products put together. And this interference could conceivably happen in any house or office in towns or even large cites.
2. A user won’t be able to get away from PLT interference. As the interference is very strong it may be difficult to identity the culprit as they could be anywhere within reasonable distance.
3. As it is associated with computer use, PLT may be on as long as Internet connection is connected meaning there is no escape for HF users. So what should you do?
If you suspect that you are suffering from interference, there are a number of resources available on the RSGB EMC Committee website (http://www.rsgb.org/emc/leaflets.php). Alternatively, Ofcom can provide advice and assistance to those who complain of interference to radio communications equipment. Individuals who wish to report specific cases that may be caused by PLT apparatus, or any other source, should contact Ofcom’s advisory team on 0300 123 3333. Icom UK Marketing - marketing@icomuk.co.uk
17/12/2009