I have noticed my Internet connection has been rather slow of late and yesterday we had guests and all computers were off. I don't know what made me look but I noticed by wireless router was lit-up like a Christmas tree! It seemed apparent my Internet connection was being used by others but my area is populated with mainly family and retired types. I remembered that a group of 'lads' must be renting a house at the back and assumed those boys had hacked into my connection which was unsecured since getting the macbook (couldn't seem to get security working). Anyway I switched off the router and got on with our evening.
This morning I re-configured the router adding security shared key on all wireless computers, all was well. Until.....a few hours ago again I experienced a 56k like connection so switched off all computers but the router was flashing away indicating someone using the wireless service.
Sat in a darkened corner I thought I need to reduce the power of the wireless output but the router menu did not show anything of this sort. I googled WRT54G (my router type) and found lots of third party firmware. Reading and researching I found a popular free firmware supplier DD-WRT (
http://www.dd-wrt.com/dd-wrtv2/index.php ) I uploaded v23 on to my router and it all worked. 5 minutes was spent slowly reducing power output from 28mW (default) to 5mW. I have 3/4 signal strength at 54Mbit/s with no apparent difference in performance. Incidentally power can be increased to a colossal 251mW approx 10X the output power as standard from the Linksys firmware.
30 minutes into using 5mW I have no gatecrashers to my Internet connection but time will tell. I can drop it down output power further if need be.
What those lads were downloading I do not know but they were using all bandwidth I had! - Not any more.