CAMPBELL@UTOROCI.BITNET (01/13/89)
We have a 3/260C with the colour monitor in one room and the monitor in
another, connected with about 50 ft or stock rg59. Worked fine. Then we
got a "Matrix Multicolor" video camera ("really" a Dunn 638HSC, but Matrix
bought them, and now Agfa has Matrix. Many piesces of the thing seem to be
built by Nippon Avionics.) That worked fine too, with the Matrix set to
Hi-Z, tee'd directly into the video about 4 ft from the monitor (which is
permanently 75ohm). Then we got a TAAC, through which the video loops at
the Sun. That works fine too, WITHOUT the Matrix attached - with the
Matrix hooked up, there is noticeable ghosting on the Sun and Matrix
screens. The ghosting covers a distance of several mm - one or two
character widths.
The input DC resistance of the Matrix measures 10 kohm, and I cannot
duplicate the problem with resistors in its place - even at 100ohm, the
video is dim, but there are no reflections. The problem endures with the
Matrix turned off, unplugged, and with many of its internal connections
open. It goes away unless the TAAC and Matrix are both hooked up.
Has anyone got any experience with the Dunn camera on a Sun? (It's in
Catalyst.) Are there gotchas that could be at work? We have asked our
electronics shop to put together a buffer (actually a buffered switchbox -
we want to share the Matrix with other monitors) with Hi-Z inputs and
75ohm output; any reason to suspect that that won't work?
Thanks,
Chip Campbell,
and Sun
VAX^ System Manager
Physics Division, Ontario Cancer Institute, Toronto.
Bitnet: campbell@utoroci