[OT] Monitor switch - advice appreciated

[FishMurderer]

Evening all,

I'd like to use my PC to switch between my 21" CRT monitor, and an Epson
projector using a switch box. Any recommendations as to what gear would
give good results? The PC monitor is right next to the PC, but the
projector cable would need to be around 3 metres long, so it can be
located properly.

Has anyone found a good product for this? I don't really want a cheap n
nasty switch-box without signal amplification if it's going to cause
problems with the 3m cable.

Thanks for any input.

Mark (UK)

 

[HockeyTownUSA]

Evening all,

I'd like to use my PC to switch between my 21" CRT monitor, and an Epson
projector using a switch box. Any recommendations as to what gear would
give good results? The PC monitor is right next to the PC, but the
projector cable would need to be around 3 metres long, so it can be
located properly.

Has anyone found a good product for this? I don't really want a cheap n
nasty switch-box without signal amplification if it's going to cause
problems with the 3m cable.

Thanks for any input.

Mark (UK)

VGA or DVI?

 

[William]

Anything over 1 meter long is going to have a hi-frequency roll off coming
out of a computer video card. Possibly ringing, and ghosting thrown in. Be
it VGA, DVI, S-Video, or RGB. A cheep switch can be a can of worms causing
ringing and ghosting due to improper termination and cross-bleeding.

Allot depends on the quality you are looking for, how large of a budget you
have, what your personal tastes are, and how long of a run you are talking
about.

(I have on occasion seen cheep stuff work just fine - the draw of the luck)
But as a professional, I would get the catalogue out and look for
distribution amps, good shielded switches, and
oxygen-free-crystalline-aligned copper wire with double shielded wire for
the runs. AND DO NOT RUN YOUR CABLE ANYWHERE NEAR A POWER LINE.
NO-NO-NO-NO. Kick me in the butt - many times. I had to pull a conduit run
and install new conduit to fix one hum-bar problem. Major loss. Passive
and active hum blockers would not fix this one.

I can't recommend any equipment, the market moves too fast and I haven't
cracked a catalogue for a long time. I used to get stuff from Radio Shack.
I don't even know if they are into this stuff anymore. The local wholesale
electronic parts supply shops used to have good video / audio cable. (They
might scratch their heads if you ask for QUALITY video or audio cable, you
never know who knows what.) Fry's has good stuff if you know what you are
looking for.

Are you running video? Lordy say it ain't so. Maybe you are half blind,
can't see color, or drunk and non of this makes any difference. Just go
down to FredMeyers and buy a video switch and some cable and see what
happens.

William

 

[HockeyTownUSA]

I run two ten feet DVI cables going to a KVM and then running through a six
foot cable to my monitor with no issues. I did however go through about five
different sets of cables before I found ones that worked.

I also have a 15 foot DVI cable running to a projector parallel with a power
cable with no issues, but does not pass through a KVM.

Biggest thing to consider is a good quality shielded cable, and expect to
try a few different versions of cables. To be honest, I spent nearly $400
for cables and a switchbox, and it didn't run nearly as good as the $100
DVI/PS2 KVM box and $80 in cables that I ended up using. Trial and error,
unfortuantely, is the way to go.

As far as VGA, that can exhibit ghosting, but again, it has to do with
getting a high quality cable. Here again, I found some VGA cables that were
cheap that worked better than an expensive one.

Moral of the story is that expensive cables don't necessarily mean best
cables, and trial and error is unfortunately the key.

 

[William]

Your experience is typical for what I have found for consumer use. I have
set up systems for government agencies, surveillance systems, test and
observation labs, church organizations, productions houses, sales floors,
and consumer installations. Each setup has vastly different expatiations
and what is acceptable. Try projecting computer information up on a 15 foot
wall.

I tell the customer to put one hand over one eye, and squint the other -
Looks Great! Really, the lines are doing dances and colors are
psychedelic. It's not fair to stand 2 feet away from a 15 foot projection
and complain about fuzzy lines and images.

Hi-frequency roll off is always present, more or less, over 3 feet of cable
on computer boxes. They just don't have enough low z to drive much more than
a few feet before things begin to go funny. It becomes most noticeable
around edge detail. Pre-emphasis is often used in distribution amps to
compensate for this. Ringing is a big problem in cheep equipment and cable.
The signal reflects off of bad termination and shows up on top of the main
signal, like ghosting on off-air television reception.

Often, 'expensive' equipment / cable is in name only. You have to know your
vender. It is truly amazing how much difference good quality cable can
make. Oxygen-free crystalline-aligned copper wire can add 1.4 to 2db
increase in s/n ratio, and an extra mhz in hi-end frequency roll off. And
yes, I have seen cheep stuff do just fine for some installations.

Often when BIG MONEY was on the table, we would have an 'old fashion
shoot-out' between venders. They would bring in their boxes, projectors,
cable, whatever was needed. We would hook up systems in test configurations
and see what each could do. The venders, customer, sales reps, and
engineers (me) would all be their. I'd get out my test equipment, wiggle a
few knobs, kick a few boxes, trip on a few wires to see how everything would
hold up. It was fun. Trust in equipment is built over time through such
experiences.

Hum coupling only comes into play with runs around 50 feet or more. I have
run video feeds thousands of feet long around critical installations where
hum is a problem to contend with. Never run video/computer cables in the
same conduit that has power lines in them. You will be sorry.

You should try some oxygen-free crystalline-aligned copper Monster cable on
your sound system. You can hear a big difference in the low-frequency
delivery of sound. Same thing with audio runs, it is less susceptible to
noise pickup, can be run further without signal degradation, and is often
smaller in diameter compared to the competition. Often when I run small
installations, I like to purchase my audio/video/computer cables with ends
on them from quality venders I know have good stuff. One less problem to
contend with.

Unfortunately most people don't know or care about quality of the product
used in installations. They only like what they see and here and what the
bottom line is.

I guess I am rattling on.

William