Thanks for the replies.
And the good information - I would have spent a long time digging and still not have found the links provided.
I downloaded a "regular" netinst iso, and did a fresh install from that, choosing the MATE desktop. Networking (including wireless) works.
So, the problem was solved.
But I do find it strange that although the "live"
standard iso does have (and use) wireless networking for installation, the installed system apparently is not set up to use it, at least without some "surgery".
Note that the full-desktop live isos do install working wireless networking. I have previously used this with the live GNOME, XFCE and LXDE isos. So why not the standard live iso?
It also seems strange that the standard live iso does not offer to install any desktop, or even window manager. It only installs a cli interface.
I also want to note that I uninstalled a perfectly good installation of another distribution to install from the Debian live standard iso. With only one computer, with no other system installed, having only one cd drive, and no "working" networking, not a whole lot of fun.
BTW, the live iso (and the netinst) were not defective, checksums were fine on both the images and the cds burned from them.
And, the installation from the netinst iso does use the ath9k wireless driver (open source, free) to drive a wireless network adapter that uses the Atheros AR9285 chipset. As usual, no problem there.
Bottom line:
1) use the netinst.iso to install.
2) do not use the live "standard" iso for much except amusement (and aggravation and wasted time and effort).
3) the installation procedures for Debian still (after all these years) need a lot of work.
4) the Debian documentation could use a "clean-up". There's quite a bit of it, but it often feels like it is written "by technicians, for technicians", and it's not always user friendly.
Thanks again for your time.