Slow OS X wireless connections

I've had issues with wireless connections at hotels with my Powerbook (running Tiger) before, but last week showed me just how weird it is.

• My wireless connection was slow, but my dad's Windows XP wireless connection was fine, even though he was sitting right next to me.


• Browsing the Internet with Firefox (3.x) was slow, but was faster in Safari.


• The wireless connection would start off with full bars then suddenly go down to one or two bars.

A Google search came up with recommendations to turn off IPv6 support in OS X as well as Firefox, but it made no difference to me, though on occasion for the next couple of days, the connection would have an adequate speed. And this doesn't happen with all other wireless connections at other places.

It's possible that the hotel I was at was running 802.11b, as 11 Mbps were shown, while another hotel I was at last week was probably running 802.11g, as there was a reported speed of 54 Mbps. It's speed was fine, even at a two bar signal strength. Still, why would Windows XP not have a speed issue?

Is there some other answer out there, within my power, that might fix speed issues like this?