Bizarrely enough, the problem seems to have resolved itself.
I was just getting ready to log in to the router to change
the channel manually to something better and the
network was detected. Hmmm.
I did update the kernel on this machine today ... ???
I also installed kismet in hopes of sniffing out the problem --
perhaps that did something to the configuration.
"Any sufficiently advanced technology is indistinguishable
thanks for the advice everyone ...