[AusNOG] Powerline Adapters

Tue Feb 21 09:08:46 EST 2012

IIRC, they're doing OFDM - so you're no longer limited to having one 
device transmitting at a time like you were with the older units - they 
can split the available 500mbps down to say 128mbps out of unit 1, 
192mbps out of unit 2, and 192mbps out of unit 3.   I'm not sure if 
you're still limited to half duplex though - one would hope not..  That 
they claim to be getting 500mbps out of 46MHz of bandwidth, is rather 
impressive..  I'm guessing that with it extending up to 68mhz, you'd 
have to be in an area which *didn't* have Analogue TV reception, to get 
the full 500mbps..?

I know the Belkin 200mbps units that I have sitting on a shelf here only 
managed to *just* hold up ~50mbps in our last house (with about 8m 
between them..).. But totally dropped out every time my PSK31 rig sent a 
beacon on 14MHz! - and would take ~5 minutes to re-sync after that.  
Which is why they're sitting on a shelf ;)  That said, I had some of the 
original 14Mbps units - and they did a 30m run for 5 years with no 
problems at all, before a lightning strike took out one of the units..

A couple of links:
http://en.wikipedia.org/wiki/OFDM
http://en.wikipedia.org/wiki/IEEE_1901
http://en.wikipedia.org/wiki/HomePlug

Cheers,

DG

On 21/02/2012 8:37 AM, Skeeve Stevens wrote:
> Hey all,
>
> Re: 
> http://media.netcomm.com.au/public/assets/pdf_file/0012/89886/NP504-Spec-Sheet.pdf
>
> Does anyone know conceptually how these things work?
>
> At home I have hard core walls where wireless is practically useless, 
> so a while ago I installed the 100mb version of the Netcomm power line 
> devices.  My life has been happy every since, albeit at 100mb - which 
> is a bit poopie.
>
> I will be buying the above to get more speed to the server I access at 
> home which isn't in my office, but.... I wanted to know if anyone 
> understood HOW these things actually work.
>
> In an ethernet environment you have a cable, it speed is dedicated to 
> that cable.
>
> But these devices are not point-to-point - but maybe they communicate 
> that way?. At home I have them in 4 different rooms, and they all talk 
> to the server... but I don't know how, or, most importantly, how well 
> these units operate.
>
> If these new devices are 500Mbps - what does that mean.  Does it mean 
> on a point-to-point link with only two of them, it is 500Mbps.  What 
> happens when you add a third, fourth or fifth unit.
>
> So... (A) being the main unit in the lounge with the server attached, 
> and (B) being home office 1, (C) being home office 2 and (D) being 
> bedroom (we have a Boxee box! ;-)
>
> I guess the question is, what is the speed when B,C,D are all talking 
> to A, and what is happening is A and B are talking and C and D are 
> talking - do they 'interfere' with each other?
>
> If they are on the same power circuit, using the same 'frequency' (I 
> don't know what it is called) - or is it like wireless - with channels 
> or... ok, I am doing my head in.
>
> I'm really interested to know how these work, because I could see them 
> being useful in that running 500Mbps for up to 200m could be a very 
> interesting last ditch, or interim solution in the right situation.
>
> I am sure people here have had some experience with these kinds of 
> things.  They claim they 'just work' and given I have 4 of the units 
> at home with never a single problem or bit of config done, I can 
> attest to that.
>
> *Skeeve Stevens, CEO*
>
> eintellego Pty Ltd
> skeeve at eintellego.net <mailto:skeeve at eintellego.net> ; 
> www.eintellego.net <http://www.eintellego.net>
>
> Phone: 1300 753 383 ; Fax: (+612) 8572 9954
>
> Cell +61 (0)414 753 383 ; skype://skeeve
>
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>
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> www.linkedin.com/in/skeeve <http://www.linkedin.com/in/skeeve>
>
> PO Box 7726, Baulkham Hills, NSW 1755 Australia
>
>
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>
>
>
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-- 
Damien Gardner Jnr
VK2TDG. Dip EE. GradIEAust
rendrag at rendrag.net - http://www.rendrag.net/
--
We rode on the winds of the rising storm,
  We ran to the sounds of thunder.
We danced among the lightning bolts,
  and tore the world asunder

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