[mythtv-users] Power Line Network Connections
Simon Hobson
linux at thehobsons.co.uk
Mon Sep 27 18:06:27 UTC 2010
Brian Wood wrote:
>Anyone have any experience with any of the
>various powerline networking units being sold?
> ...
>My brother's place is a newer home that should have
>relatively clean AC wiring.
Just bear in mind that even "good" mains wiring
has more in common with an antenna than it does
with a high speed data cable. The RSGB are not
alone in finding problems with the "spurious"
emissions from some of these units
(http://www.rsgb.org/plt/) - our CAA (aviation)
and BBC (broadcasting) are also starting to
express concerns
(http://www.theregister.co.uk/2010/08/12/power_line_networking/)
since the drive for ever faster networking is
pushing the frequencies used higher up and into
areas where they may affect more than what has
been described in terms like "a few bearded, old
fashioned, and inconsequential radio hams".
<rant>So far, OfCom have defended doing nothing
on the basis that the units aren't designed to
transmit and so the don't have any power to
prevent their use.
Hopefully at some point our Trading Standards
and/or Office of Fair Trading will step in and
we'll see some prosecutions for importing
equipment that clearly cannot have passed any
form of EMC testing to verify compliance with our
technical standards.</rant>
Wieslaw Kierbedz wrote:
>My experiences with 802.11n (wi-fi 300Mb) under linux are very uninviting.
>Every card I tried (only ath9 - different chipsets from atheros) works
>very slow.
>I mean none have worked properly.
I don't know if they exist in 11n versions yet,
but the 'dongles' that bridge between ethernet
and wireless work quite well. Ie, once set up,
the unit connects to the wireless and bridges to
ethernet - so your client device needs nothing
but the standard ethernet driver.
Also, again probbaly a bit premature, but a good
use for redunant wireless routers is to reflash
them with OpenWRT or ddWRT and then use them as a
multi-port client bridge.
Raymond Wagner wrote:
>>>In North America its "3-wire, single-phase, mid-point neutral".
>>>The 2 hot conductors are 180 degrees out of phase. Ref:
>>>
>><<it is sometimes incorrectly referred to as "two phase>>
>
>So a 120° offset counts as a phase, but a 180°
>offset doesnt? That doesn't make sense...
What you get in the US is a single phase 220V
tapped off two terminals of the local step down
transformer. The 220V winding is centre tapped so
that you get a 110-0-110 supply across 3 wires -
giving the benefit* of having both 110 and 220V
supplies at the same time.
* As someone living where 230/240V is the
standard and we seem to get by using it for
everything, I'm not particularly convinced that
having this dual voltage is much of a benefit -
other than not having to replace all your 110V
stuff by switching wholesale to the higher
voltage.
Brian Wood wrote:
>What I am NOT familiar with is what to do when
>confronted with a totally illogical "no more
>wires" attitude from members
>of the opposite sex (no offense to the
>well-informed ladies on this list). Please note
>than a lot of men are just as
>capable of silly attitudes, but of course none of them are on this list.
How about deliberately making it crappy compared
to the other TVs in the house. When she
complains, you can tactfully suggest "well you
know honey, I could make it just like the rest if
you'd let me ..."
--
Simon Hobson
Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed
author Gladys Hobson. Novels - poetry - short stories - ideal as
Christmas stocking fillers. Some available as e-books.
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