How to set up a parabolic antenna WLAN

I'm completely new to this and need help setting up a WLAN using a 2
parabolic antennas. I live on top of a mountain and want to set up an
ADSL internet connection through a dedicated phoneline located in the
village at the bottom of the mountain (with a clear view from here)
1.5 miles away. I've looked around the internet to try to answer my
questions, but can't figure out what equiptment is needed: 1)at the
phoneline end, between the ADSL modem and the first parabolic antenna;
and, 2) at the top of the mountain, between the second parabolic
antenna and my computer's router.

This kind of long-range WLAN stuff here in Japan is still much in its
infancy. I called a specialist about setting up this system for me,
and he wanted about 3000 dollars for the job. So I thought I'd jump in
and try to do it for myself.

"Doiku" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) om...
> I'm completely new to this and need help setting up a WLAN using a 2
> parabolic antennas. I live on top of a mountain and want to set up an
> ADSL internet connection through a dedicated phoneline located in the
> village at the bottom of the mountain (with a clear view from here)
> 1.5 miles away. I've looked around the internet to try to answer my
> questions, but can't figure out what equiptment is needed: 1)at the
> phoneline end, between the ADSL modem and the first parabolic antenna;
> and, 2) at the top of the mountain, between the second parabolic
> antenna and my computer's router.
>
> This kind of long-range WLAN stuff here in Japan is still much in its
> infancy. I called a specialist about setting up this system for me,
> and he wanted about 3000 dollars for the job. So I thought I'd jump in
> and try to do it for myself.

Two Smartbridges Outdoor Airbridges
One ADSL Modem
One Broadband Router

Plug the modem in to the DSL line, plug the modem's ethernet in to the
router. Connect the LAN side of the router in to the AirBridge, point the
AirBridge at your house, and take the second AirBridge to your house. You
can probably guess the last step. ;P

Jeremy Parr wrote:
> "Doiku" <(E-Mail Removed)> wrote in message
> news:(E-Mail Removed) om...
>
>>I'm completely new to this and need help setting up a WLAN using a 2
>>parabolic antennas. I live on top of a mountain and want to set up an
>>ADSL internet connection through a dedicated phoneline located in the
>>village at the bottom of the mountain (with a clear view from here)
>>1.5 miles away. I've looked around the internet to try to answer my
>>questions, but can't figure out what equiptment is needed: 1)at the
>>phoneline end, between the ADSL modem and the first parabolic antenna;
>>and, 2) at the top of the mountain, between the second parabolic
>>antenna and my computer's router.
>>
>>This kind of long-range WLAN stuff here in Japan is still much in its
>>infancy. I called a specialist about setting up this system for me,
>>and he wanted about 3000 dollars for the job. So I thought I'd jump in
>>and try to do it for myself.
>
>
> Two Smartbridges Outdoor Airbridges
> One ADSL Modem
> One Broadband Router
>
> Plug the modem in to the DSL line, plug the modem's ethernet in to the
> router. Connect the LAN side of the router in to the AirBridge, point the
> AirBridge at your house, and take the second AirBridge to your house. You
> can probably guess the last step. ;

I'll supply the equipment and do the configuring for his estimated price
of $3,000. Might even buy the airline ticket and hotel room to go
onsight for that price. He wouldn't need parabolic dishes unless the 2.4
spectrum is polluted in that area. A couple of cheap 19dbi panels would
do it admirably.

Doiku <(E-Mail Removed)> wrote:
> I'm completely new to this and need help setting up a WLAN using a 2
> parabolic antennas. I live on top of a mountain and want to set up an
> ADSL internet connection through a dedicated phoneline located in the
> village at the bottom of the mountain (with a clear view from here)
> 1.5 miles away. I've looked around the internet to try to answer my

http://www.nodomainname.co.uk/Equati..._broadband.htm

---
Clarence A Dold - Hidden Valley (Lake County) CA USA 38.8-122.5

In article <(E-Mail Removed) >, (E-Mail Removed) (Doiku) wrote:
>I'm completely new to this and need help setting up a WLAN using a 2
>parabolic antennas. I live on top of a mountain and want to set up an
>ADSL internet connection through a dedicated phoneline located in the
>village at the bottom of the mountain (with a clear view from here)
>1.5 miles away. I've looked around the internet to try to answer my
>questions, but can't figure out what equiptment is needed: 1)at the
>phoneline end, between the ADSL modem and the first parabolic antenna;
>and, 2) at the top of the mountain, between the second parabolic
>antenna and my computer's router.
>
>This kind of long-range WLAN stuff here in Japan is still much in its
>infancy. I called a specialist about setting up this system for me,
>and he wanted about 3000 dollars for the job. So I thought I'd jump in
>and try to do it for myself.

I suspect when all is said and done, you are not going to beat his price by
as much as you are thinking.

On 17 Apr 2004 17:36:48 -0700, (E-Mail Removed) (Doiku) wrote:

>This kind of long-range WLAN stuff here in Japan is still much in its
>infancy.

There is a logarithmic relationship between the line-of-sight range
and the antenna amplification.

10 dB gain means that the range is multiplied by 10 (provided line og
sight between two identical directional antennas)

13 dB gain: range x 20
16 dB gain: range x 40
20 dB gain: range x 100

The calculations are, however, complicated by the fact that antenna
gain is measured in two different (often unspecified) ways: dBd or dBi
(the difference is between 2 and 3 dBs beteen the two as far as I
remember.)

Another problem is that at wi-fi frequencies (2.4 GHz) the antenuation
loss in the coax antenna feeder is MUCH higher than with e.g.
television cables.

If you use ordinary inexpensive RG-58 50 Ohm cable the loss is about 1
dB per meter.
LMR-400 cable has a loss of about 0.2 dB per meter but is more
expensive and difficult to find (if you build the antennas yourself.)

I would guess you need 2 unidirectional antennas with a gain about
15-18 dBi with short antenna feeder cables to get a really stable
connection. But the better the gain the less vulnarable to
interference it will be.

In some countries very high gain antennas could infringe on some radio
regulations ( I have no idea if that is the case in Japan but it could
well be a theoretical problem...)

Alex

Thanks a lot for the replies.
Another alternative for placement of my phoneline/ADSL modem at the
bottom of this mountain is the home of my boss (a good friend). His
house is geographically closer but the view to his house is hidden by
another small mountain. Is it possible to bend the radio signal via a
repeater or bridge (and 2 more antennas)? The top of the mountain
hiding the view is only 1 kilometer away from this mounntain top with
a clear line of sight, and it's only about 600-700 meters from the top
of that mountain to his home (with a clear view). Would using a
repeater seriously diminish the radio signal strength?

I'm sorry to keep asking these school boy questions.

Desperate in Hiroshima

That depends on the repeater. Typically it is not a problem with some
descent quality gear.

Michael

"Doiku" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) om...
> Thanks a lot for the replies.
> Another alternative for placement of my phoneline/ADSL modem at the
> bottom of this mountain is the home of my boss (a good friend). His
> house is geographically closer but the view to his house is hidden by
> another small mountain. Is it possible to bend the radio signal via a
> repeater or bridge (and 2 more antennas)? The top of the mountain
> hiding the view is only 1 kilometer away from this mounntain top with
> a clear line of sight, and it's only about 600-700 meters from the top
> of that mountain to his home (with a clear view). Would using a
> repeater seriously diminish the radio signal strength?
>
> I'm sorry to keep asking these school boy questions.
>
> Desperate in Hiroshima

Doiku <(E-Mail Removed)> wrote:
> another small mountain. Is it possible to bend the radio signal via a
> repeater or bridge (and 2 more antennas)? The top of the mountain

Some folks say this really didn't work, but the story is published.

Part one
http://www.pbs.org/cringely/pulpit/pulpit20010628.html
Part two
http://www.pbs.org/cringely/pulpit/pulpit20010712.html
References
http://www.pbs.org/cringely/links/links20010712.html



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---
Clarence A Dold - Hidden Valley (Lake County) CA USA 38.8-122.5