The mono monitor is almost certainly fixed frequency. You might be able to
drive it with that card using the green BNC connector - Macintoshes used
"sync on green" commonly. The trick will be configuring the card to the
correct frequency for the resolution of that monitor, which, I hope, you
know already.

You might find reading the web pages at www.xfree86.org about monitors
helpful; they describe monitor technology in enough detail that you might
be able to make a go of it. I'd also hit the Radius and SuperMac web sites;
you may be able to find old tech support & software for that display card.
I'd recommend getting it to work under MacOS first, so you know its modes,
and then move on to NetBSD.

	Erik <fair@clock.org>