Hey,

so, my parents finally moved a few weeks ago and they currently set up their iMacs using AirPort. Now, my mum's iMac is more or less as far away from the router as my dad's - but the signal seems much better, it just always works and pretty fast so. Now, when I check, my dad's signal seems always to be rather strong - but sometimes, the signal just interrupts and the iMac keeps looking for an Airport network around. Sometimes, you have to restart until it gets back to it again. Huh?

Pete

[P]

First up: Check the firmware on the Airport. There have been issues recently, in particular with version 7.6.3. Get the latest and see if that helps.

Other than that, I can see two options

a) That there is another router at e.g. the neighbor that your dad sees but your mum doesn't, and that that router is on the same or an adjacent frequency band, has the same SSID or something like that
b) That there is some sort of obstruction (water pipes, in particular) that makes the distances unequal.