BBC highlight problems with Powerline Communication Technology to
radio services
The BBC has pointed out
the radio interference problems caused Powerline Communication
technology systems (PLC), also known as Broadband over Powelines.
The BBC say these systems can not only cause problems for broadcast
radio services but to broadcast television and to all other
radiocommunication services operating in the bands where interference
might be generated. Additionally they pose a threat to conventional
broadband telecommunication services.
The BBC’s specific concerns are:
Low frequency mains signalling systems are proposing to use PLC and
extend the present band above 150 kHz to 540 kHz. In Europe this will
impact longwave and some medium wave broadcasting services.
Present systems are using all the high frequency bands, and have to
notch out certain frequencies to reduce interference to services such as
amateur radio. There are technical difficulties regarding the notch
depth, but despite this there are proposals for a higher power levels to
enable reduce operational costs. The widespread use of the technology
for SmartGrid may prevent the rollout of the planned DRM services.
Permanent notching of the Broadcast bands is not considered practical,
and there is some opposition to using an active dynamic notching technology.
There are serious concerns that the technology will adversely affect
Band II services. It is noted that the FCC have limited PLC to below 80
MHz in order to protect Band II services. Many Band II receivers have
inadequate out of band response performance to protect against
interference from PLC in nearby bands. Similarly Aeronautical services
in the VHF band need protection. There is nothing that receivers
(broadcasting, aeronautical, etc) can do to reject in-band interference
from PLC and little that can be done to existing receivers to reject
adjacent channel PLC.
There have been some reports of PLC interfering with DAB (in Band III)
services; however products operating in the VHF spectrum are at present
limited – possibly by the desire for them to be marketable in the USA.
The BBC concluded that:
“There is a need for PLC networks that cannot readily be met by present
wireless systems; however it is unlikely that the current PLC technology
could comply with current interference standards.”