Re: OFCOM report on PLT's (Home Plug Networking)

On Mon, 28 Jun 2010 18:32:50 +0100, Bob <bob@xxxxxxxxxxxxxxx> wrote:

On 28/06/2010 17:59, Jeff Liebermann wrote:
On Mon, 28 Jun 2010 17:06:57 +0100, Bob<bob@xxxxxxxxxxxxxxx> wrote:

<http://www.ofcom.org.uk/research/technology/research/emer_tech/PLT/pltreport.pdf>

"Smart Notching has been investigated within ETSI with guidelines for
signal detection and notch depth published in 2008 [8]. Plugtests,
carried out in 2007 by ETSI using Sony and DS2 smart notching
demonstrators, have shown the feasibility of smart notching and have
given the encouraging results that shortwave radio stations were
received as well when smart notching was activated as when there were no
PLT devices active [9].

Please note that Smart Notching requires a *TRANSMITTER* to determine
what frequencies to notch. The full name is Adaptive Smart Notch,
which installs a notch in the broadband noise transmitted by the
device if it detects a qualifying transmitted signal. That's
tolerable for some ham operation, which usually transmits at or near
the same frequency as reception. It's useless for receive only HF
signals, such as DRM stereo, SWL, packet radio monitoring, HF APRS
gateways, and others, where there's no transmitter available to
convince the device to shut up.

From 5.3.4 in the Ofcom report.
Smart notching is estimated to be available from Q3 2010.
This provides a monitoring function in the chipset which
will detect the presence of transmissions to which PLT devices
may cause interference and apply a frequency notch as appropriate.

They noted that some form of monitoring with BT systems should take
place as this seems to be an installation specific problem and perhaps
some form of "advice" on installation issued.

The stuff radiates well beyond your house. I pickup junk from BPL
systems that are about 500 meters away. Probably farther if I had a
decent antenna.

I am in the process of moving house and all the phone sockets in the
new house are next to mains sockets so when I have time I will experiment.

There's no interfernce between BPL/PLT and POTS phone service.

--
Jeff Liebermann jeffl@xxxxxxxxxx
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
.