has anyone here had the 'Airport not found' issue?

At random intervals I get the above message and I have to reboot the Mac to get an Airport connection again. And when I do I'm asked if it's ok to join the wireless networks on my list - everytime.

Another thing that fixes it is do a software update from Apple.

I tried trashing prefs, zapping, resetting psu and what else, but a malfunction pattern didn't emerge.

Because it's intermittent I'm struggling to understand if it's an hardware issue (airport failing) or something else.

I'll take to an apple centre soon, but anyone here has had a similar issue?

thanks already