I know a lot less than I'm going to post.

Q What is the maximum distance from a wireless router or access point?
A It depends on power output and chipset design and the type of wireless standard used.  802.11b is currently the longest range wireless standard because the FCC allows for more transmit power (up to 200mW) than 802.11g or 802.11a.
Access point made by manufacturers like Linksys, Dlink and Netgear because they use low quality chipsets with only 40mW to 80mW of transmit power they can generally reach up to 1500 feet outdoors.
Enterprise grade equipment from Cisco and Proxim has up to 100mW of transmit power and can reach up to 2000 feet outdoors.
Long range wireless access points with up to 600mW of transmit power can have a range of up to 1200 meters or almost 4000 feet outdoors!  The only manufacturer with long range cards is Engenius Technologies click here to see the equipment.
The transmit power of your access point and client card have can greatly effect the range.  Generally though it depends on your situation. Metal and Concrete can cause degradation in the signal, as well as microwave ovens and 2.4 GHz phones. If setup properly, a wireless access point or router will give you up to 150 feet indoors and up to 4000 feet outdoors with stock antennas.

FROM:  http://www.keenansystems.com/wififaq.htm

 remember Google is your friend,  I found this by typing       antenna transmit wireless 2000 feet -rfid -camera   

the reason for the -rfid and -camera was to eliminate those terms from my search, it might be helpful to remove 2000 feet and replace it with long distance