[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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