xpyttl wrote:

I have been able to go laptop to laptop almost a mile with normal PCMCIA
cards, using patch antennas. (Well - normal cards modified to bring out the
signal to the antenna.) These antennas can be astonishingly directional.
Indeed, at 2.4 MHz, it is pretty easy to get antennas with amazing amounts
of gain.

There are restrictions on the RADIATED power, transmitter output power,
etc of unlicensed 2.4gHz transmitters, such as WiFi. You should check
them out. They vary from country to country.

If you have a ham license, then you can use 2.4gHz for data transmission,
but then you are restricted in transmission mode, encryption and data
content.

For example, the infamous Pringles can antenna was developed in the U.S. by
an FBI agent in the course of an investigation. It's use as a WiFi transmission
antenna is illegal in many places. The well pubicised long distance link in
Egypt was illegal.

Here in Israel we are limited to 100mW EIRP for civilian useage, except
for ham satellite operations which are limited to 25w.

BTW, there are limitations in the U.S. too, I just don't know them.

Geoff.

--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM
IL Voice: (07)-7424-1667 IL Fax: 972-2-648-1443 U.S. Voice: 1-215-821-1838
Visit my 'blog at http://geoffstechno.livejournal.com/