What s a "good" signal?

I am trying to use Netstumbler to see where I get the best signal in
the house and how well my (home made) reflector works. Windows XP will
never say I have anything other than a "low" signal, though it does
report that am getting 11Mbps.

Netstumbler gives me varying signal strengths even when very close to
the access point....at the moment I am in direct line of sight and
less than 6m away from it, and it's giving me between -57 and -88 and
peaking at -50 but with no noise at all. Is this a reasonably good
signal for being righ near the AP?

Now I move to the lounge where I intend to do most of the wireless
work, and the signal drops to an average of -75, but still with no
noise.

This is my first few days with wifi and I know no-one else using it
either so have nothing to compare it to, but what is a "good" signal?

--
Bryan Anderson <www.anderson-it.com>