Re: iBOOD special: Belkin F5D8235nv4 wireless router

[Jon Wilkins <jonpdwilkins@xxxxxxxxx>]

That product does 11n but if you read the small print you will find it
only
does 802.11n (or anything else) in the 2.4Ghz band -- so you'll be running
in the same band as your neighbours 11g devices -- which will likely dent
the performance you get (depending on how close they are or if they are on
the same channel).
Keep in mind there are only 3 non-overlapping g channels (1, 6 & 11)
and
that to get the "300mb" quoted air rate with n you will be using
the 40Mhz
bandwidth that effectively glues adjacent channels ... ie you'd be using 1
=
&
6 or 6 & 11.

Does n give improvements?  Generally, n (compared to g) will give you
faste=
r
connection speed at the same distance from the AP **OR** similar speed at a
greater distance (or proportional combinations).  Just as with b or g, n
will drop speed as you get further from the AP, so dont expect to get
300Mb/s air rates when you're 100 m away.

Also keep in mind that the N standard, even in its now final & ratified
state, has options in it -- N can work in either 2.4Ghz or 5Ghz but many
vendors of APs and laptops choose only to support 2.4Ghz (this is usually
i=
n
cheaper / SOHO kit).  Another option is the 20/40Mhz "bonding
channels"...
if you dont bond 2 channels you're instantly halving that max quoted
300Mb/=
s
.  And then there's the number of radios... N supports 2 spectral streams
(effectively parallel radios) to give max 300Mb.s or 450Mbs with 3.  But
there are some devices on the market that only have 1 -- so max they would
ever do it 150Mb/s.

As you can see from above if your AP or laptop only did 2.4Ghz with 1
stream, 20Mhz then you'd be getting a max air rate of 75Mb/s and you'd be
i=
n
the same congested band as all your neighbours.  Oh... and the final point
is that all these rates (54Mb/s, 300Mb/s etc) are all air rates.  Once you
take off all the OSI layer headers your usable application data is usually
approx 45%-55%.

So yes, N can & does deliver what it should do but you need to know
what of
the options the kit will support and dont expect to get 300Mb/s throughout
your country estate from just one AP.

/jon

2009/10/23 Nick Austin <nick.w.austin@xxxxxxx>

>
>
> Details:
>
> http://www.ibood.com/uk/en/product_specs/13684/Belkin_Wireless_N_Router_w=
ith_USB-port_/
>
> Normally closer to =A380, today it's =A340 + =A38 delivery.
>
> This does 802.11n, albeit from slightly before the standard was
> finalised. Does anyone have experience of 802.11n and know if the
> claims made about it are true (i.e. faster, wider coverage, better
> immunity from interference than 802.11b/g)?
>
> Nick.
>=20=20
>


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