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Signal through stone building

Author
13 Feb 2005 4:29 PM
Jeff Mowatt
Hi all,

I installed a netgear FWAG114 hotspot in my loft with the aim of reaching
neighbouring buildings within 100m
Surprisingly I have managed to connect indoors on all floors, which I don't
need to do but the signal just outside is very weak. The building itself,
constructed circa 1860 is solid stone with walls up to 18" thick and I'm
wondering whether this is the major factor affecting transmission. There
shouldn't be much interference as I'm in a valley where cell phones don't
operate.

I'm wondering as I don't have access to the other buildings right now,
whether it might be better a little further from the house where these walls
don't fall in the "line of sight".  Otherwise I might well need a wap with a
dipole antenna for all round coverage, perhaps if not some building to
building bridges in some cases. I'm try to work out if that's going to be
economically viable.

A quick question. Though I can't seem to find any specific information, are
all 802.11g devices compatible in that I might use equipment from other
manufacturers to propagate my signal? I'm thinking CISCO which according to
the Cisco logo on my Netgear box, is from the same stable and they have some
reasonab;y priced equipment in comparison.

Regards,

Jeff

Author
13 Feb 2005 4:43 PM
Jeff Mowatt
PS: I meant to say 3COM not Cisco, have relatively inexpensive kit.
Author
13 Feb 2005 6:21 PM
Robert Jacobs
Yes, all 802.11g products that are Wi-Fi certified should in theory work
together. The only option that will not work most of the time are the so
called speedboosts and such. You can not take advantage of thier 108Mbs
ratings.

As far as your stone wall, yes they can block signals going to your external
areas. You could just use outdoor APs and that would provide you with
excellent outdoor coverage.

If wanting to go from one building to another then setup two nets, one in
each building, buy an Outdoor AP for each building and bridge them together,
making one large network.

Robert....

Show quoteHide quote
"Jeff Mowatt" <Ilovespam@btinternet.com> wrote in message
news:cunv9q$lqd$1@titan.btinternet.com...
> Hi all,
>
> I installed a netgear FWAG114 hotspot in my loft with the aim of reaching
> neighbouring buildings within 100m
> Surprisingly I have managed to connect indoors on all floors, which I
> don't need to do but the signal just outside is very weak. The building
> itself, constructed circa 1860 is solid stone with walls up to 18" thick
> and I'm wondering whether this is the major factor affecting transmission.
> There shouldn't be much interference as I'm in a valley where cell phones
> don't operate.
>
> I'm wondering as I don't have access to the other buildings right now,
> whether it might be better a little further from the house where these
> walls don't fall in the "line of sight".  Otherwise I might well need a
> wap with a dipole antenna for all round coverage, perhaps if not some
> building to building bridges in some cases. I'm try to work out if that's
> going to be economically viable.
>
> A quick question. Though I can't seem to find any specific information,
> are all 802.11g devices compatible in that I might use equipment from
> other manufacturers to propagate my signal? I'm thinking CISCO which
> according to the Cisco logo on my Netgear box, is from the same stable and
> they have some reasonab;y priced equipment in comparison.
>
> Regards,
>
> Jeff
>
Author
13 Feb 2005 7:16 PM
Jeff Liebermann
On Sun, 13 Feb 2005 16:29:47 +0000 (UTC), "Jeff Mowatt"
<Ilovespam@btinternet.com> wrote:

>I installed a netgear FWAG114 hotspot in my loft with the aim of reaching
>neighbouring buildings within 100m
>Surprisingly I have managed to connect indoors on all floors, which I don't
>need to do but the signal just outside is very weak. The building itself,
>constructed circa 1860 is solid stone with walls up to 18" thick and I'm
>wondering whether this is the major factor affecting transmission. There
>shouldn't be much interference as I'm in a valley where cell phones don't
>operate.

Cell phones are not an issue because they're on different frequencies.
Brick and stone are serious attenuators at 2.4Ghz.  They will
literally block the signal completely.  This article may help explain:
  http://www.wi-fiplanet.com/tutorials/article.php/1431101
18" of solid stone is good for about 12dB attenuation (or more).  To
put that in perspective, you're power gets cut in half for every 3dB
of attenuation, and your range gets cut in half for every 6dB of
attenuation.  The wall will cut your range to 1/4th or less.

>I'm wondering as I don't have access to the other buildings right now,
>whether it might be better a little further from the house where these walls
>don't fall in the "line of sight".

YES!  Since you can't move the walls or drill through them, moving the
radios to some approximation of line of sight will be a minimum
requirement.  A better antenna (or antennas) will also be a huge help.

>Otherwise I might well need a wap with a
>dipole antenna for all round coverage, perhaps if not some building to
>building bridges in some cases. I'm try to work out if that's going to be
>economically viable.

Replacement antennas are common.  Netgear supplies two antennas that
my guess would be about 2dBi gain. 
  http://www.netgear.com/products/details/FWAG114.php
I suggest you leave one antenna in place to deal with local
conenctions, and attach an external panel antenna pointed in the
direction of the remote user in question.  However, make sure your
coax cable runs are as short as possible, and that you have line of
sight to between the user and the panel antenna:
  http://www.fab-corp.com/J1.htm

>A quick question. Though I can't seem to find any specific information, are
>all 802.11g devices compatible in that I might use equipment from other
>manufacturers to propagate my signal? I'm thinking CISCO which according to
>the Cisco logo on my Netgear box, is from the same stable and they have some
>reasonab;y priced equipment in comparison.

In general, everything that's claimed to be 802.11g will talk to each
other.  However, the exceptions are a problem.
1.  There are 802.11g enhancements such as Super-G, Turbot-G, and
Afterburner, that are not universally compatible.
2.  Repeaters and WDS bridges are always a problem.  The standards are
not terribly clear and implimentations vary.  Some manufacturers have
repeaters that don't even talk to their own hardware due to different
chipsets being used.  I assume this is what you mean by "propogate"
the signal.

Are you thinking of a wireless repeater or WDS bridge?  If so you need
to make sure the manufactory support the product or at least the
chipset used in the FWAG114.  I can't tell from the insipid Netgear
data sheet if it supports WDS.  If so, methinks that's your best bet
if you can find a WDS access point to act as a repeater through a hole
in the wall.  I'm not a big fan of repeaters and WDS bridges, but they
do work.  Methinks antennas and location are more important and
useful.  Here's more than you wanted to know about WDS:
    http://www.proxim.com/support/techbulletins/TB-046.pdf


--
Jeff Liebermann    je***@comix.santa-cruz.ca.us
150 Felker St #D   http://www.LearnByDestroying.com
Santa Cruz CA 95060    AE6KS  831-336-2558