net said:
in aiming for the highest powered wireless device for a desktop pc it
occurrs to me there must be something better than the long-range pci and
pcmcia cards I've seen for sale. Is there such a device or are we all stuck
with these cards? I know about yagi antennas and such and I know the antenna
is important for range and power but I wanted to start with the
transmitter/reciever first and see what the best thing around was. I'm
interested in fixed location equipment, I don't need mobility. Thanks for
any pointers.
Something you should investigate, before going further, is the FCC
(or your local equivalent thereof), has rules for both unlicensed and
licensed uses of the airwaves. That means, I cannot emit more than
a certain power level, on my RF transmitter, unless I want to get
in trouble. The rules are there, to allow the multiple users of these
services, to all play together.
http://www.ddj.com/architect/184411700
If you use a wireless product, complete with original antenna, then
you can be sure you're staying within the rules. That would be a PCI
card with the antenna that came with the product, or a PCMCIA card
with the antenna that came with the product. Not with an amplifier
strapped to the thing, or large high gain antenna.
The FCC may not be driving around in a truck, looking for trouble-makers.
They'll instead be triggered by complaints. Say, for example, a local
cellphone operator, is suffering service outages in your neighborhood.
The FCC man comes to investigate, finds the offending transmitted frequencies,
uses a few antenna trucks to triangulate the source. Then you get the
knock on the door.
I can give you a more concrete example. In my city, one day, all the garage
door openers that operate on a certain RF frequency, stopped working. (Some
people couldn't get their garage door open.) It was discovered, that a powerful
transmitter was operating in the city. (One theory was, it was located on the
roof of a certain embassy!) It took several days, before the problem "went away",
without any details being released to the press about the offender. So, if
there is an offense, like illegal power levels, used on an RF device, finding
and tarring the individual takes time.
If you want to read some amusing articles on Wifi and distance, try
world's record wifi
http://www.engadget.com/2007/06/19/venezuelans-set-new-wifi-distance-record-237-miles
http://www.dailywireless.org/2003/01/06/worlds-longest-wi-fi-connection/
I think I read an article in the past, about one of those mountain to
mountain project, which went into some details, about things like
whether the time constants in the standard protocol, allowed distances
like that or not. And you can see in that picture, that they're using a
pretty fancy high gain antenna.
HTH,
Paul
