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From: Steve Fenwick on 11 Jan 2010 03:01
In article <ql9lk59akv7fhgp8dm1j3j54odau13nlr8(a)4ax.com>,
Jeff Liebermann <jeffl(a)cruzio.com> wrote:

> On Sun, 10 Jan 2010 14:37:33 -0800 (PST), Billz <billz1(a)msn.com>
> wrote:
>
> >Can someone let me know the latest in getting a house, guest house and
> >the outdoor areas set-up for Wi-Fi?
>
> Nope. No numbers to work with. How far? How fast do you need (i.e.
> video)? Any potential interference problems? Going through walls,
> trees, or windows? Connections to roving laptops?
>
> >I can't imagine a state of the art
> >wireless N covering major areas.
>
> 802.11n (MIMO) is all about speed, not range. Getting an "N" router
> and client radio will NOT improve range much.

It won't necessarily improve range at the lowest data rates, although
having more than two transmit and receive streams at each end may help
one get lucky and make a connection where a single stream with antenna
diversity does not.

802.11n will help maintain a faster connection over a greater
range--that second (or third) stream, even at a low rate, will aggregate.

> >Repeaters seem to be questionable.
>
> Repeaters work under some situations. I don't think your layour would
> work too well. The problem is that you have at least twice as many
> packet flying around with a repeater. That slows things down, causes
> some collisions, adds to the interfence, etc.

WDS might help, but it divides the available bandwidth. It might work to
have a couple of point-to-point links as a backbone, and local 802.11n
nodes for coverage.

Steve


> >Is
> >the a way to completely ring in an area both indoors and outdoors?
>
> No.

--
steve <at> w0x0f <dot> com
"Life should not be a journey to the grave with the intention of
arriving safely in an attractive and well preserved body, but rather to
skid in sideways, chocolate in one hand, chip shot in the other, body thoroughly
used up, totally worn out and screaming "WOO HOO what a ride!"
From: atec 77 "atec on 11 Jan 2010 10:03
Billz wrote:
> Can someone let me know the latest in getting a house, guest house and
> the outdoor areas set-up for Wi-Fi? I can't imagine a state of the art
> wireless N covering major areas. Repeaters seem to be questionable. Is
> the a way to completely ring in an area both indoors and outdoors?
>
> Thanks in advance
You need to supply specific information about the site situation and
your aspirations
it is of course achievable but can you afford it ?
From: Jeff Liebermann on 11 Jan 2010 12:26
On Mon, 11 Jan 2010 00:01:45 -0800, Steve Fenwick
<nospam(a)nospam.invalid> wrote:

>> 802.11n (MIMO) is all about speed, not range. Getting an "N" router
>> and client radio will NOT improve range much.
>
>It won't necessarily improve range at the lowest data rates,

Think about it. If you're going for maximum range, the tendency is to
also run the AP at the slowest speed. Slow means best signal to noise
ratio, which results in the best range (assuming no interference). In
general, if you have range problems, you'll end up with non-MIMO
speeds and protocol.

On the other foot, the 802.11n committee did quite a bit to maximize
range at MIMO speeds. Basically, it uses the available bandwidth more
efficiently thus allowing *SLOWER* over the air data rates for the
same desired thruput. That results in some S/N ratio improvements,
but they're not huge. Spatial diversity also offers some additional
immunity to frequency selective fading and multipath.

Even so, the bottom line is still the same. If you want range, you're
going to have to go slow.

>although
>having more than two transmit and receive streams at each end may help
>one get lucky and make a connection where a single stream with antenna
>diversity does not.

True in a highly reflective environment such as indoors. Not true for
an outdoor point to point link, where both ends of the link follow
exactly the same path. MIMO only works if you have different (length)
paths between the client and wireless AP.

The problem here is that there's zero information about the layout,
topology, environment, or available equipment required. All I know is
that it's "wide area" and "outdoor". To me, that means directional
antennas and long range, which means forget about using MIMO. Note
that there are no commercial MIMO high gain antennas (yet). Similarly,
there are few access points with coax connectors and removable MIMO
antennas. The reason is simple, directional MIMO doesn't work.

>802.11n will help maintain a faster connection over a greater
>range--that second (or third) stream, even at a low rate, will aggregate.

Sure. However, that's not true in the most common MIMO situation, the
laptop and USB dongle. These are now coming with single stream 1x1
MIMO which (in my never humble opinion) is not MIMO. However, the
keepers of the Wi-Fi trademark disagree:
<http://www.smallnetbuilder.com/wireless/wireless-features/30804-buyers-beware-single-stream-draft-80211n-products-bring-back-spec-spin>
So, the sticker may say MIMO, but with only a single stream, there
isn't going to be much of an improvement over 802.11g.

>> >Repeaters seem to be questionable.
>>
>> Repeaters work under some situations. I don't think your layour would
>> work too well. The problem is that you have at least twice as many
>> packet flying around with a repeater. That slows things down, causes
>> some collisions, adds to the interfence, etc.
>
>WDS might help, but it divides the available bandwidth.

Yep. Think of WDS (wireless distribution service) as just a more
efficient store and forward repeater.

>It might work to
>have a couple of point-to-point links as a backbone, and local 802.11n
>nodes for coverage.

Maybe. I've had zero luck with WDS when the clients can hear more
than one access point in the WDS network. By necessity, all the WDS
nodes have to be on the same channel, making self interference the
major problem. If you need a demonstration, setup a WDS network with
all the AP's in the same room. Good luck trying to get any
throughput.

Good reading:
<http://www.airmagnet.com/assets/whitepaper/WP-802.11nPrimer.pdf>


--
Jeff Liebermann jeffl(a)cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
From: Bob on 11 Jan 2010 13:12
On 11/01/2010 17:26, Jeff Liebermann wrote:

> The problem here is that there's zero information about the layout,
> topology, environment, or available equipment required. All I know is
> that it's "wide area" and "outdoor". To me, that means directional
> antennas and long range, which means forget about using MIMO. Note
> that there are no commercial MIMO high gain antennas (yet).

Aruba do have a 14dB Antenna for the 5GHz band but the data about it is
negligible.
<http://www.arubanetworks.com/pdf/products/ap-ant-93_ss.pdf>

"The antenna integrates 3 differently polarized elements in a single
antenna radome. Dual Slant +/-45� and Vertical polarisation."



From: Jeff Liebermann on 11 Jan 2010 15:27
On Mon, 11 Jan 2010 18:12:58 +0000, Bob <bob(a)invalid.invalid> wrote:

>On 11/01/2010 17:26, Jeff Liebermann wrote:
>
>> The problem here is that there's zero information about the layout,
>> topology, environment, or available equipment required. All I know is
>> that it's "wide area" and "outdoor". To me, that means directional
>> antennas and long range, which means forget about using MIMO. Note
>> that there are no commercial MIMO high gain antennas (yet).
>
>Aruba do have a 14dB Antenna for the 5GHz band but the data about it is
>negligible.
><http://www.arubanetworks.com/pdf/products/ap-ant-93_ss.pdf>
>
>"The antenna integrates 3 differently polarized elements in a single
>antenna radome. Dual Slant +/-45� and Vertical polarisation."

Thanks. I hadn't seen that abomination. It seems to be a
polarization diversity contrivance intended to connect to a MIMO
access point (or bridge). That actually will work, sorta. If one
path between endpoints is right hand circular polarization, and the
other is left hand, they are sufficiently well isolated to be
considered seperate paths. So, you'll get at least 2x2 MIMO for a
wireless bridge. However, the third vertically polarized element is a
waste of effort. It will be picked up by both the RH and LH CP
antennas, and has exactly the same path length as the CP antennas, and
is therefore more a source of interference than a usable path. There
will be a -3dB loss due to different polarizations, but that's
negligible. However, I'm wondering if it can be made to work by
simply inserting a small delay in the 3rd vertically polarized
element.



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