Wireless Problem

have to WaveLan Access points 25 miles apart
link test shows connection is excellent and throughput should be good. has 8 meg Bronze Turbo card in each. Can only get 45k accross the connection have run a network analyzer on it and see no problems. Have an associate in another state with the exact same setup and he is getting 4.5 mbps across his connection. Have checked everything under the sun that I can think of. there is only one pc connected via hub on the remote end so I know its not a bandwidth usage problem the local end is run through a HP 4000 switch. Both units have be updated with the latest software and configuration. What could be the problem?