A friend of mine wish to set up a long range internet service so he
wants to know the things that will be needed. He wants it to cover at
least 10Km. Is there any gadget that can convert the normal RJ 45
signals to radio so that it can be transmitted. I need to know More
please help.

wrote:

A friend of mine wish to set up a long range internet service so he
wants to know the things that will be needed. He wants it to cover at
least 10Km. Is there any gadget that can convert the normal RJ 45
signals to radio so that it can be transmitted. I need to know More
please help.

The most important question is where are you?

Radio signal strength is measured in Watts EIRP (look it up in the wikipedia).

WiFi (wireless networking devices) are rated in output power, most are 100mW
(100 miliwatts, 1/10th of a Watt) but some high power ones can be gotten that
are 200mW.

With the little antennas on them they radiate a pattern that looks like a
sphere (ball). By narrowing the pattern, you reduce the area the signal
covers except in the pattern itself. This is called a beam antenna.

For each time you narrow the pattern by a factor of 4, you increase the EIRP
by 4 and double the distance covered.

The reason I asked where you are, is that in the US, the EIRP limit is 1 watt
(10 times normal) for portable devices, but 4 watts (40 times normal) for
point to point (from one stationary place to another).

This would require you to have relay stations (look up MESH networks)
aproximately every 1.5 to 2 km.

The problem with all of this is that many countries don't have such generous
power limits. For example, Israel has a limit of 100mW EIRP.

You may also want to look up WiMax, which is supposed to have a much longer
range than WiFi. Before the devices were sold, it was claimed to be as much as
10 miles. Once the first devices came on the market, it was reduced to one
mile in practice.

That was a while ago, depending upon how well WiMax actually does, how
good your antennas are, what's in the way, it may do the job with one
"hop".

Geoff.
--
Geoffrey S. Mendelson N3OWJ/4X1GM
To help restaurants, as part of the "stimulus package", everyone must order
dessert. As part of the socialized health plan, you are forbidden to eat it. :-)

On Mon, 9 Aug 2010 12:54:35 -0700 (PDT), "
wrote:


A friend of mine wish to set up a long range internet service so he
wants to know the things that will be needed. He wants it to cover at
least 10Km. Is there any gadget that can convert the normal RJ 45
signals to radio so that it can be transmitted. I need to know More
please help.

Line of sight? If yes, very high gain very directional antennas on
both ends of a WiFi repeater setup will work well. This is done
commonly in cities and from cities to outlying areas where line of
sight can be supported. The solution won't be cheap, the WiFi
equipment is expensive, as are the antennas and towers. Add to that
the cost of setup...

There are a lot of commercial solutions, some pre-packaged. Try
Google.