Hello,

I'm certain the question has been asked before about how to setup a simple
wireless connection between two buidlings; so, I apologize for being
repetive.

The application is on a farm.  I am using PC's running Windows 98se.
Presently I have a wired network setup.  There is a cable modem, hooked into
a router.  Two PCs are also hooked into the router; these PCs share files
and the internet connection.  There are also two network webcams hooked into
the router (this provides us with offsite, remote monitoring ability).  None
of this equipment is wireless.  (The router is about 50' from the exterior
wall of the building that faces Bldg2 - see below.)  All of the above is in
Bldg1.

There is a second building, Bldg2.  A stand-alone PC is in Bldg2, it has no
network connection.  Bldg1 and Bld2 are 150' apart and in direct line of
site.  The computer in Bldg2 is about 15' into the interior and not in
direct line of site with Bldg1.  I want to connect the PC in Bldg2 with my
network in Bldg1 in order to share the internet connection.  It is not
practical to run a wire between these buildings.

Any suggestions on how to do this.  I am willing to replace the router in
Bldg1 with a wireless one (prefer to use Linksys).  Also, I prefer to hook
into the PC in Bldg2 using a wired ethernet card (already installed in the
computer) so I assume that I will need either a wireless router or AP in
Bldg2 which I then plug the computer into.

Thank you for any guidance you can give me.

Bruce

BL wrote:
Where does it get it's electrical power from? Think about doing it in a low
cost way, rather than think about doing things the high tech expensive way.
Chances are, if it is a building on a farm, the electrical comes off a
transformer by the street and, then routed to the buildings.. Means there is
already wiring between the buildings. They not only make "power line
networking", but they also have phones, intercoms, radios, tv, multimedia,
etc over power lines. For devices with a ethernet and/or USB jacks that
plugs into AC plugs, and run at speeds of about 10 Mbps... Check out
http://www.plugtek.com

If you are curious, the devices that plug in at various locations are about
$50 each. (you will need two, so it will be about $100)

Thanks for the suggestion about powerline networking devices.  I had
considered this; however, the two building are on two completely different
services (meters, drops, etc.)  Also, there is not common telephone service
between the buildings.

Bruce

BL wrote:
Too bad, when you said it was a farm, I was hoping one drop.. Oh well, If
you ever have a yacht, they work great off a single generator.. :)

On Sun, 6 Mar 2005 03:08:11 -0600, in alt.internet.wireless , "BL"
<blnospam@hotmail.com> wrote:

(snip long description of what is essentially: two buildings ~150ft apart,
router in one 50ft from wall, PC in 2nd, unspecified distance from wall)

Aside from using powerline networking, I'd suggest putting a wireless AP
close to the outer wall of building 1, with an antenna on the outside
facing building 2, and a similar wireless reciever in building 2 with an
antenna facing building 1. Some APs can be set in reciever mode (i forget
the proper name for the mode).

Show quote Hide quote ability).  None
above is in
Show quoteHide quoteSeeing how you like linksys, a couple of wap54g's would work.
You can run them both in bridge mode, or if you want wireless in
Bldg1 you can run one of them in AP mode and the other in
AP Client mode.Just connect the one in Bldg1 to your existing router
and the one in Bldg2 to the ethernet card.
If you can place both near a window facing each other it might work
right out of the box. If you dont get a good connection you can always
put a different antenna setup on them.

In article <422aef6b$0$22518$2c56e***@news.cablerocket.com>,
Airhead <campb***@alliancecable.net> wrote:
Show quoteHide quoteYou'll probaly benefit by directioal antennas at one or both ends.
Google for "wifi cantenna", which should be fine. It's eith DIY or can
be purchased.  

In  general, antennas  need to  be  line-of-sight and  the coax  cable
between the AP and the antenna should be as short as possible, a small
# of feet, so yoiu wind up  pulling enternet insode the house to reach
the AP/antenna  location.  the  AP can be  powered over the  CTA5 wire
(google "POE power  over ethernet") People put the  AP antenna outside
in weatherproof plastic boxes.

These are easy to hook up just plug in USB port and will have no problem at
that short of distance.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=5755948360&ssPageName=STRK:MESO:IT

Show quoteHide quote

Show quote Hide quote Because of the number of devices you currently have connected to
your existing router it probably would be best to keep it as is
and simply add a wireless link between the buildings.

Several different Linksys models will do what you want, as will
equipment from other manufacturers.  I personally would use
WRT54G units, even though they are overkill for what you want.
They are very common, inexpensive, and are supported by third
party firmware which makes them very versatile.  (Who knows what
you'll think of to use all of this for in the future...)

The trick with a link between buildings in understanding what
"line of sight" means with a 2.4GHz radio path.  No trees, no
walls, and no occasional vehicles, all of which can block the
signal.  Walls made only of wood are not good, but can be dealt
with.  Walls that have aluminum foil backed insulation, have
chicken wire to hold up plaster, or are made of concrete, will
totally block the signal.  So will trees or shrubbery that you
cannot see through, as will any vehicle parked in the wrong
place.

Hence...  indoor antennas are best if placed in a window on an
upper level.  Outdoor antennas are a problem because the gain
they provide is lost in the feedline unless you buy expensive
semi-rigid coax.  Mounting the equipment itself outdoors, on an
elevated antenna mount, is another way to provide good service.
Suffice to say, outdoor equipment is significantly more complex
and expensive.

The ideal example would be facing second story windows in each
building.  Any number of different kinds equipment models could
be used, but I'll describe a pair of WRT54G's.

Download third party firmware (Satori from Sveasoft or the latest
HyperWRT firmware) and install it.  Configure one unit as an AP
and the other as a client.  Mount them in the windows and run
CAT5 cable to the router in Bldg1 and to the PC in Bldg2.

At 150' you should have a very solid link.

Note that if you do not mount the units in a window or use an
external antenna that is outdoors, it will probably not work at
all initially, and if it does it will almost certainly suffer
from frequent signal dropouts.  However, it might be possible,
with experimentation, to find exactly the right place to locate
the units where they will work.

I do the same thing with a building that is perhaps 100-120 feet
away.  The walls don't have any metal in them, and by moving
each unit around and looking at signal strengths, I did find a
place where they do work (one is at ground level, the other is
on the second story because signal loss on the first floor was
too frequent). Typical signal strength runs about -75 dBm or
better, with occasional fades down to -81 dBm or so (caused
mostly by multipath fading when vehicles drive by, or park, on
the street between the two buildings).

Post more information about the specifics and you'll get
significant input on your project as you go along.  Different
people here can provide real expertise on just about every
aspect of your project.  You don't need to ask right now about
things like how to run CAT5 cable or how to configure your PC or
the WRT54G, but when you get to those points... do post again as
new hurdles need to be jumped.

Thanks to all who have replied.

Floyd from Alaska seems to have keyed in on a simple setup that I can
handle, but I still have a couple of "novice" questions.

1.  Using two WRT54Gs will work for me.  When setting these up I presume
that in Bldg1 the WRT54G is configured as an access point and hooked via a
CAT5 cable to my existing router.  Is this correct?

2. Bldg2 will have the WRT54G configured as a client and I hook this via
CAT5 cable to the ethernet card in the computer.  Correct?  The WRT54G in
Bldg2 will sit near a window with clear line of site to Bldg1.

3. Bldg1 is a metal building.  I can place the WRT54G near the exterior
wall, but I presume an external antenna placed on the outside of the wall
(facing Bldg2) would greatly help the signal.  Any suggestions on which
antenna to buy?

Again thanks to all.

Yep.  Either the WAN port or one of the 4 LAN ports can be used.
I use a LAN port.

Make that *in* the window!

Note that either end could be the AP and the other the Client.
The end that is an AP can have other wireless clients connect to
it, while the end that is a client cannot.

Another possibility is to make *both* ends an AP, and enable one
of them as a WDS repeater.  This allows other wireless clients
to connect to it too, but has the possible disadvantage that the
througput is cut in half.  That may or may not be significant.

Because wireless operates with simplex radios, using the same
channel for both transmit and receive, they can't do both at the
same time.  Hence in normal operation the radios switch back and
forth between transmit and receive.  The actual maximum
throughput will be about half the rate that data is transmitted
at (because half the time is spent receiving).  Hence an 802.11g
unit is a 54Mbps unit, but because of the simplex operation (and
packet overhead), the actual maximum bitrate you'll see is
probably right at about 26Mbps or a bit less.

If the unit is used as a repeater, it has to transmit in both
directions, as well as listen in both directions, hence the bit
rate gets halved again.

However, if most or all of your traffic is directed to a typical
Internet connection, which will be more than an order of
magnitude slower, it simply won't make any difference.  It would
show up on file transfers, for example, between local hosts
connected via the wireless network.  Running an X window display
over a wireless is noticeably slower than a 100Mbps ethernet,
but faster than a 10 Mbps ethernet.

It makes no difference where you place the unit inside a metal
building, it simply will *not* go through the walls.  It must
either be in a window, or have an external antenna.

To use an external antenna you need to put the unit as close to
the antenna as possible because at 2.4Ghz the loss through
almost any kind of practical feedline is relatively great.  It
makes no difference what kind of feedline you use if it is 100
yards long!  That's almost like going through the metal walls!
(Actually, 100 yards of cheap coax cable does have a name.  It's
called a "dummy load", which is a useful device for testing
transmitters without actually radiating a signal.)

Note that the distance from your PC, which is connected with
CAT5 using ethernet, is not really important at all.  It could
be a few hundred feet long and work fine.  Hence you want to put
the WRT54 right at the point where the feedline to an external
antenna enters the building.  You want that to be as near as
possible to the point were an external antenna can be mounted
with a clear line of sight view of the distant antenna.  Think
in terms of inches of feedline rather than feet!  100 inches is
a lot of feedline unless you spend some real money on something
like 1/2" semirigid coax or even larger heliax.  If you use
typical 1/2" low loss coax, keep it less than 6 feet long if at
all possible.  If you use even smaller coax, think about less
that 24 inches.

To be more specific, the loss through coax runs something like
0.1 to 0.5 dB per foot.  A 3 dB loss is the same as reducing
your transmit power by 1/2.  Even good coax is going to eat half
your transmit power with a 30 foot length of line, and with less
than optimal coax... well its a nice dummy load.

What you need depends on the structure of your building.  Post a
few more details, and we can probably tweek Jeff Liebermann into
providing the right part numbers for coax.  He can also advise
you about antennas too.

On Sun, 06 Mar 2005 13:51:44 -0900, fl***@barrow.com (Floyd L.
Davidson) wrote:

Well, the official maximum length is 100 meters (328ft).  However, if
you're careful, you can go much further.  100baseTX will not work
because the timing on the collision domain limit the cable length to
about 500ft.  I've had problems with 100baseTX whenever I tried it.
100baseTX-FDX (full duplex) is even worse due to crosstalk errors.

The only way to make it work is using 10baseT-HDX (half duplex).  I
think that the WAP54G and WRT54G allows forcing the interface protocol
to 10baseT-HDX but only on the WAN port.  The LAN ports are running
the NWAY protocol and will set their own speed.  Not good.  So, my
usual fix it to excavate out of the junk heap an old 10baseT hub.  The
hub goes between the WRT54G LAN port and the typical ethernet switch.
Ugly, messy, but effective at keeping the speed at 10mbits/sec.
Sometimes, I have the luxury of a managed ethernet switch available,
which allows me to select the speed of an individual port.  No hub
required for these.

Anyways, for 10baseT to the wireless router LAN port, I've been able
to hang 950ft of cable.  Actually, it worked through the entire 1000ft
roll of CAT5E, but I needed 50 ft before it was installed.

Why me?  Never mind, don't answer.

My favorite coax cable is LMR-400 from Times Microwave:
  http://www.timesmicrowave.com/wireless/index.shtml
  http://www.timesmicrowave.com/content/pdf/lmr/22-25.pdf
You'll need a crimping tool ($40), a pile of RF Industries male N
connectors ($5/ea), and a pigtail to connect to the access point
($18).  If you don't wanna make your own, then you can purchase
pre-cut and connectorize lengths:
  http://www.fab-corp.com  (See "cables section")

At 2.4GHz, LMR-400 looses 0.068dB/ft.  I haven't worked out the link
budget or fade margin so I don't know how much loss your link can
tolerate.  Too many unknowns.  However, let's say you don't wanna
loose more than a total of 6dB in the coax and connectors.  The
pigtail and 3 sets of connector pairs will eat about 3dB.  That leaves
3dB loss available in the coax cable.  At 0.068dB/ft, that's 44ft
maximum coax.  That's not too horrible for short links using fairly
high gain antennas.  However, since a 50ft jumper cable with
connectors costs about $50, you might wanna think about mounting the
radio near the antenna and using CAT5 to connect to the computah, as
Floyd D. suggested, instead of using all that coax.  Anyway, give me
some specs and I'll work out the link budget and recommend antennas.
One spec that I need is the MINIMUM acceptable thruput in mbits/sec.

I'll do a preliminary guess and suggest you adjust the numbers
accordingly.  We have a "half mile" range and I'll assume you're going
to follow our advice and NOT use a huge coax run.  Medium size dish or
panel antenna on the OUTSIDE of the building.  1-3ft LMR-240 coax
pigtail with R-TNC and N-male connectors.  I'll assume a speed of
12Mbits/sec OFDM which will yield about half that in thruput speed.
  TX power =  +15dBm
  TX coax loss = 4dBm
  TX antenna gain = +14dBi
  Distance = 0.5 miles
  RX antenna gain = +14dBi
  RX coax loss = 4dBm
  RX sensitivity = -84dBm  (12Mbits/sec OFDM)
  Desired fade margin = ????
http://www.terabeam.com/support/calculations/som.php
yields a fade margin of 20.8dB which is just fine.  This should work.
However, everything you do to compromise the above calcs will cause
reduce the fade margin.  When it gets down to about 15dB, it will
become flakey and unreliable.

So, you need antennas with a gain of about +14dBi.  See:
  http://www.fab-corp.com
under "antennas parabolic" and "antennas panel".  I like the Maxrad
panels (mostly because they're cheap and simple).

Floyd and Jeff thank you both for extremely thoughtful and complete replies
to my inquiry.  I won't pretend that I fully understand the significance of
all the details you both have given me; if I did I would not have needed to
ask the question in the first place as to how to accomplish the simple task
of running a wireless network connection between two buildings.

That being said I believe between your posts I have sufficient information
to get the job done.  I will follow the advice from both of you and put the
radio device in Bldg1 to achieve the shortest possible antenna run, no more
that 6 feet.  Jeff's information on the antenna and the links provided are
exactly what I was looking for.  Thanks much.  I check back if I run into
trouble when setting this up or with the configuration.

Floyd, just thought I'd ask if you know Fran Tate from Barrow.  I hear her
occassionally on Chicago radio - what an interesting personality.

Bruce

Fran has sworn me to secrecy.  I'm not allowed to talk about her
on The Internet!

That is because somebody who knows her in Chicago clued me in
that she won't wear seat belts, even in Chicago.  (I don't here
either, but I drive Suburban, and rarely ever go more than 25
mph, which makes it only half as crazy.  Any place other than
Barrow...  I won't move even *one foot* without a seat belt on.)
Anyway, it seems they have fits with her, trying to get her to
use a seat belt.  She puts the belt over her lap to look like
its there, but won't buckle it.

(For everyone else's benefit, Fran is about 70 years old, can
easily wear out two healthy people half her age on any given
day, and is just more fun than I can possibly describe.)

Anyway...  I was told about this seat belt stuff, so I go over
to Pepe's North of the Border Mexican Restarant (and Fran always
sits down and has a chat with me for all or most of the time I'm
there).  I tells Fran that I've got _the_ scoop on her.  She
told me I was goofy as a loon in the spring.  I said, no really!
I have spies, and they report to me on the Internet.  So she, in
total disbelief says something to the effect of I'm bullshitting
her, and it just ain't so.  So I looks her dead in the eye, and
says, "Fran, they tell me you won't wear a seat belt in Chicago!
Shame on you!"

She shrieked and jumped a foot in the air!  hee hee heeeeeeeee.


Now, what you might not know is that besides owning a fine
Mexican restaurant that can also put a Japanese spread out that
makes Japanese tourists think they are in Osaka...  Fran only
owns a restaurant because she can't cook.  Yep, she needed an
excuse to hire a cook.  Or so she says...

What she actually is, is an EE who came to the North Slope right
after oil was discovered a Prudhoe Bay as the field engineer for
the installation of power plants on oil drilling rigs.

She also knows personally every jazz musician in the country.
And about 30 years ago she was on Johnny Carson's show, and
presented him with a polished petrified penis bone from a
walrus, and let him spend considerable time examining it before
she told him exactly what it was.

Guess I better shut up...

On Sun, 06 Mar 2005 21:47:42 -0900, fl***@barrow.com (Floyd L.
Davidson) wrote:

She's already on the internet:
  http://www.demko.com/cg020315.htm
  http://www.alaskajournal.com/stories/100101/foc_pepes.shtml
  http://www.moxiemag.com/moxie/articles/profiles/tacos.html
Interesting lady...

Jeff Liebermann <je***@comix.santa-cruz.ca.us> wrote:
I'd never seen these before!

This article is confused about dates, but not in any way that
makes a difference.

That one is very well done!  Note that Jim Vorderstrasse, who is
quoted frequently, is just about as much a character as Fran is!

That one is a good article too.

Beyond description really.

In fact, there is a major part of what Fran is that is not told
in any of those three articles, though there is a hint of it.
They mention things she does around Barrow... easter, and so on.
But note that people in Chicago know her too.  So do folks in
Nevada, and parts of California and in East Saint Louis.

For perhaps a dozen years, which unfortunately had to end the
past year, Fran has gone to a children's hospital in Chicago and
handed out a fuzzy stuffed animal of some kind, with a smile and
some cheer, to every child in the hospital.  For the last couple
years I helped her select the particular stuffed animal that she
ordered (something like 900 of them).

For the past two or three years she adopted an elementary school
in East Saint Louis.  I don't remember the name of the school,
but it was described to me as "the poorest school in the United
States".  This year we picked wool beenie hats (because one size
fits all), and she sent 500 hats to the school, one for every
child there.

When I say "we picked", let me add at little more to this story,
because while that "we" does include me, my part is very very
small.  I happen to have a logo on the side of my truck that
says "LaBamba Gift Shop" and on occasion I've been referred to
as a "partner".  Actually I'm not, but I've been known to hug
the lady who owns it.  She would also cut my head off if she
knew I mentioned her name, but Stacey Cha is the owner of the
LaBamba Gift shop.  She was born in Korea and  educated
there, before coming to the US in the early 1970's.  I don't
want to say too much, but lets just say she was definitely not
an under privileged young lady growing up in Korea!

She and Fran get together and plot these projects.  It is Fran
doing it, but Ms Cha makes it easier.  She is in the business of
buying these various types of items, so she finds reasonable
sources to make bulk purchases, and gets them at cost for Fran.
(When Fran had dealt with other local merchants in the past,
they saw it as a great money making deal, and offered Fran
a 5% discount...)

You just can't imagine how much fun it can be to have dinner
with these two ladies, which I get to do on a regular basis.
Quite the privilege!

(Of course... there's more to this whole story!  Fran's son
Joe, who must be about 50 now, is just as much a character as
his mother.  He ran the water deliver business for 24 years,
but retired from that a couple years ago.  We tease him that
the only way to get water from him now is 1 glass at time,
at Pepe's.  Whatever, his house is literally a museum, with
more local art and artifacts than the local museum has.  And,
yes he does give tours.)

And for anyone thinking of a trip to Barrow...  I get 2 or 3
people I meet on Usenet a year that visit.  I'm retired, so I
have no problem spending a couple days showing off the local
highlights.  Certainly dinner with Fran and Joe is one of the
things we do.  Anyone who has a real streak of adventure running
through their bones is encouraged to give it serious thought,
and let me know about it.

slot design
Router problem
Range extender for BEFW11S4
Connection stops responding
file & printer sharing
Home network and PDA access
XP ICS wit netgear DG834GT router ?
both wired and wireless routers in series
Building Wireless Community Networks
WAP11 HW ver 2.6 SNMP management possible ?