BPL interference
Broadband over Power Lines or BPL has been
in the news a great deal over the last year. For those who haven't caught
up what BPL is all about, here is Owen Duffy with an introduction to BPL.
Recent developments in technology have delivered chipsets designed for
transmission of high speed data at Broadband speeds over existing power
line infrastructure in a range of scopes including existing premises power
wiring, the low voltage (LV) distribution network, and high voltage (HV)
transmission network.
Power Line Communications (PLC) is not new; it has been in use for a
very long time for electricity network protection, control, telemetry,
voice and data communications, and demand side load management. Some of
these applications are more broadly captured by the term Power Line
Telecommunications (PLT).
Broadband over Power Lines (BPL) is a specialised form of PLT, it is
designed to deliver high speed data services at Broadband speeds (greater
than 256Kbps), usually delivered to the customer with an Internet Protocol
(IP) interface and principally for access to the Internet.
It is a combination of the growing demand for Broadband data services
and development of powerful digital signal processing capability on silicon
chips that has encouraged BPL.
BPL achieves the high data rates by modulation of carriers at radio
frequencies with the data, and transmission of that radio frequency energy
on the power line media. BPL does not depend on radiation of radio frequency
energy for its operation; BPL uses conduction on the metallic power line
conductors to carry the modulated data signals from the sending BPL modem
to the receiving BPL modem.
Power lines in their various forms are almost universally unsuitable
media for transmission of radio frequency energy for a number of reasons,
but most importantly to users of radiocommunications services, because
of the leakage of substantial radiocommunications energy from the power
lines and in-building wiring and the consequent risk of interference to
radiocommunications services.
Current BPL technologies mainly use the radio spectrum from about 2MHz
up to 30MHz to 80MHz (HF and VHF radio spectrum). BPL signals that leak
from infrastructure are quite unlike any other form of radio frequency
radiation,
they are wideband (typically several MHz wide for individual links) with
almost uniform power density across that bandwidth when in traffic, and
they have the potential to interfere with a very large number of radiocommunications
services used for diverse purposes.
BPL interference is a most serious threat to all radiocommunications
users, and especially to Radio Amateurs because of their use of relatively
weak signal operation, often limited only by external noise and interference.
Owen Duffy - VK1OD
WIA director Phil Wait VK2DKN has news on the WIA's action on BPL
interference.
Over the last year there have been a number of trials of Access BPL
technology right here in our own backyards.
In Hobart Tasmania, and Moruya, Queanbeyan, and Newcastle in NSW.
The WIA raised concerns about the interference from these trials. We
argued that the important social and economic values of radiocommunications
services in Australia should be protected through standards and regulation.
We put to the ACA that there was a need to consult with all
radiocommunications users on the impact of deployment of BPL technologies.
Well, the ACA has done just that, they published a discussion paper entitled
"Management of Interference from BPL" and the closing date for
submissions passed on Friday 24 of June. The WIA made a comprehensive
submission
and it is published on the WIA website.
Support your WIA's opposition to BPL Interference.
There is still a limited opportunity for you to email the ACA stating
your support for the WIA submission, details are on the WIA website at
www.wia.org.au
Phil Wait VK2DKN - National WIA.
Source: Wireless
Institute of Australia
• You'll find lots of interesting and
useful information on Owen's
website - it's well worth a look.
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