Cheap 5km wifi -- hopeless?

Please excuse my ignorance. I have a Draytek Vigor2600We router and a
cheap 19dBi antenna off eBay. I have clear line-of-sight to a house
with a good ADSL service (which I don't have), about 5km away. Is
there any chance, if I give them the router to be sited at a window
facing this way and put a wireless card in my PC attached to that
antenna and line it up carefully, that I'll be able to connect and get
a decent broadband service, or am I dreaming?
--
mind, matter, meaning and information at http://www.mmmi.org

Hi Robin,

Draytech Vigor 2600WE is an ADSL Router with built-in (indoor) wireless
Access Point which is made for indoor usage with limited wireless
power!

The issue here is the power of your Access Point not the Antenna size,
shortly you might need a signal booster of 200 -500m Watt, which can
drive enough power to 19dBi Antenna.

Also you should have the proper anetnna to reach that distance.

Good Luck!

Naim
www.networkingland.com/wifimain.htm

On Thu, 20 Apr 2006 19:03:35 +0100, Robin Faichney
<(E-Mail Removed)> wrote:

>Please excuse my ignorance. I have a Draytek Vigor2600We router and a
>cheap 19dBi antenna off eBay. I have clear line-of-sight to a house
>with a good ADSL service (which I don't have), about 5km away. Is
>there any chance, if I give them the router to be sited at a window
>facing this way and put a wireless card in my PC attached to that
>antenna and line it up carefully, that I'll be able to connect and get
>a decent broadband service, or am I dreaming?

Probably won't work. My wild guess(tm) is that you'll also need a
high gain antenna at the other end of the link. Quick check... yep,
you're about 18dB short on the fade margin.

See the FAQ under "Link Calculations" at:
| http://en.wikibooks.org/wiki/FAQ_for...k_Calculations
Go through the exercise. Make your best guess as to the power output
and sensitivity of the radios at each end. Come back with your
results if you're having problems.

Also, don't assume that line of sight also means that you have Fresnel
Zone clearance. See:
| http://www.terabeam.com/support/calc...esnel-zone.php
For 5km, you need at least 33ft radius clearance about the line of
sight line at midpoint.

--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558 (E-Mail Removed)
# http://802.11junk.com (E-Mail Removed)
# http://www.LearnByDestroying.com AE6KS

On 20 Apr 2006 14:44:55 -0700, "Panda" <(E-Mail Removed)>
wrote:

>Draytech Vigor 2600WE is an ADSL Router with built-in (indoor) wireless
>Access Point which is made for indoor usage with limited wireless
>power!
>
>The issue here is the power of your Access Point not the Antenna size,
>shortly you might need a signal booster of 200 -500m Watt, which can
>drive enough power to 19dBi Antenna.

Hmmm... So you start with a radio that puts out +17dBm and add an
amplfier/booster/kicker/loudenbelcher/whatever that increases the
power to perhaps +25dBm for a fabulous gain of 8dB. That's kinda
marginal for one direction but doesn't do anything for the other
direction. Are you perhaps suggesting that he add power amplifiers at
BOTH ends of the link? The cheapest 500mw amp that I've seen is about
$250 retail. Meanwhile, a pair of 24dBi dish antennas are $60/ea.

>Also you should have the proper anetnna to reach that distance.

It can be done with just 2 antennas and no power amplfiers. Run the
numbers first. Then offer solutions.


--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558 (E-Mail Removed)
# http://802.11junk.com (E-Mail Removed)
# http://www.LearnByDestroying.com AE6KS

> The issue here is the power of your Access Point not the Antenna size,

Sorry, that's rubbish.

> shortly you might need a signal booster of 200 -500m Watt, which can
> drive enough power to 19dBi Antenna.

As is that.

> Also you should have the proper anetnna to reach that distance.

A pair of high gain directional antennas will do the job.

David.

Robin Faichney <(E-Mail Removed)> wrote:

>Please excuse my ignorance. I have a Draytek Vigor2600We router and a
>cheap 19dBi antenna off eBay. I have clear line-of-sight to a house
>with a good ADSL service (which I don't have), about 5km away. Is
>there any chance, if I give them the router to be sited at a window
>facing this way and put a wireless card in my PC attached to that
>antenna and line it up carefully, that I'll be able to connect and get
>a decent broadband service, or am I dreaming?

Its possible - but you will need to do a link analysis to be sure. This is a
good site for link calculators:

http://www.ecommwireless.com/calculations.html

You'll need to know distances, elevations at both sites, and antenna raitings at
both sites.

On 20 Apr 2006, in the Usenet newsgroup alt.internet.wireless, in article
<(E-Mail Removed) .com>, Panda wrote:

>The issue here is the power of your Access Point not the Antenna size,
>shortly you might need a signal booster of 200 -500m Watt, which can
>drive enough power to 19dBi Antenna.

I bet you'd have a terrible time understanding a _passive_ repeater,
that consisted of exactly two "large" antennas ("simple" 28 dBi horns)
mounted back to back on a tower, and connected with a piece of low loss
transmission line (in this case, waveguide). Do the numbers, and you might
see how it works - with NO receiver or transmitter at the repeater site.
The math is "transmitter power - line loss + antenna gain - pathloss +
antenna gain - line loss + antenna gain - path loss + antenna gain -
line loss = receiver input level". In this case, the link was just over
three kilometers, with the passive repeater sitting on the top of the
hill between the sites. We used it for about five months. There was no
electrical power on the hilltop, and the local power company refused to
bring it up there. Fire regulations prevented having a generator on the
hill, and both solar cells and wind powered generators were not practical.

Old guy