So what is it you would say determines wither or not my signal will be
received on the other end? I mean with just a regular soho wifi access
point in open space you can only communicate within a couple hundred
feet (That's open space). If gain/wattage isn't so important when we're
talking distance.. what is? Line of site? Are you saying that that I
can shoot my 30mw signal from my soho access point couple of miles?

I've spoken with a guy who has set up a number of reliable
point-to-point links in the Sacramento valley, using standard
unamplified off-the-shelf SOHO-type access points and/or PCI cards or
USB dongles. He said he achieves reliable performance, with a good
margin of signal strength to handle rain fade, etc., with no
amplifiers, over distances of as much as 5 miles.

The key to doing this are a clear line of sight, an antenna with high
directional gain at each end of the link, and careful aiming. Getting
the radio right up at the antenna (rather than at the end of a length
of coax) is also beneficial.

The carefully-aimed highly-directional antennas give you several
advantages, over a standard SOHO omni antennas. The directionality
increases the effective radiated power of the transmitter (50
milliwatts through a 20 dBi antenna is equivalent to 5 watts
isotropic), it increases the receiver's effective sensitivity by the
same degree, and it makes the receiver _less_ sensitive to
interference arriving from other angles (e.g. competing transmitters).

Also, with proper choice of antenna, you can select the signal's
polarization angle. Since most home and business access points seem
to use vertically-oriented antennas (and thus a vertically polarized
signal) you can reduce interference problems by using point-to-
point antennas which are horizontally polarized.

The guy I spoke with was not complementary about the idea of trying to
"blast" signals through by using high-power transmitters or
amplifiers, and blanketing a large area with the signal.

You can buy wire-dish parabolic antennas for the 2.4-gig ISM radio
band quite easily. I think I've seen 'em advertised as having 15 to
19 dBi of gain. One of these at each end of the link would be a good
place to start.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
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