Some users have obtained an older AirPort base station to use with vintage computing hardware, so their early 802.11b cards could still get whatever level of 'security' without detracting from later wireless systems for newer devices that use a different protocol or frequency. By use of a different wi-fi for the old stuff.
An ethernet splitter or hub device can allow more than one base station to operate. A backward-compatible AirPort extreme from about 2004 could do, if you go there.
{I gave away a very nice 800MHz 17" iMac G4, it didn't see much use. Then I found the new owners had left it unplugged for a year, & with the 1/2AA 3.6V lithium battery dead, it would not start. And they got rid of it...}
Happens I have an original Apple refurbished AirPort Extreme orb last model (the high end in its day) still in the generic brown Apple box; unused and never tested at my end of the road. And that was a spare. Also I found three more used ones in second hand stores, for about $3. each. Alas, the tiny early model AirPort express does a fine job, too. I'm using one as they work with both b/n wi-fi.
Good luck & happy computing! 🙂