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- Cable interference
- Shawn Wilson
September 17, 2005, 4:51 am
rate this thread
(this is a continuation of an older thread, I thought it might be good to
Anyone who was following the other thread, sorry for the repost, but I
thought it might be good to start with a clean slate of information just in
case the point got lost in the muck.
I have a light band rolling through my video and can't find the cause. I'm
looking for a device possibly to filter out whatever noise this might be.
I am using a DVD player and it's component output to provide video to my
projector. The cable is a 50ft VGA cable because my projector uses the VGA
input for a component signal. (the projector came with a component to VGA
Things suggested and my response is as follows:
1. better cable
r: I'm more than happy to shop for a new cable, but what criteria should I
use? Saying brand X is a good cable doesn't really help me. Is there a
particular level of shielding I should look for? The cable I have says it's
90% shielded. What specification should I look for in a 'good' cable?
2. interference from things around the cable or projector.
r: I have un-plugged EVERYTHING with a plug in my appt. The TV, the
surround sound system, the fridge, the microwave, my computer, etc... Not
just shut off, but unplugged. The only two things plugged in are my DVD
player and the projector. I've never had my PC on while using the
projector, but for kicks I turned it on and the line did get worse. But
with the PC unplugged the line is still there. So while the PC does
introduce it's own noise, it's been off this whole time... it's not the
3. dirty signal / power
r: I'm now using an APC UPS to provide power to the projector. The power
to the projector is perfectly clean. The signal from the DVD player does
not introduce the light band through a shorter cable (6ft). I moved the DVD
player to the back of the room and used a short cable to the projector.
This produced a perfect picture with no light band. The projector's own
power cable being close to the signal cable had been mentioned as well, so
for good measure I put them as far apart as possible. They are now only
close where they plug into the projector and that can't change obviously.
At this point, I'm left thinking that the band must be caused by some
outside source (RF from a local radio station?) and it's not in my control
to remove the source of the interference. I'm left trying to find a way to
filter it out of the cable. There are what look like ferride core things at
each end of the video cable, but would bigger/more of them help? What about
an electronic device of some kind that can go inline with the signal cable
to filter out whatever might be causing this?
Thank you all for your suggestions. Maybe I'll just have to put up with
this, or just buy random cables until one works. I just have to believe
that there is a specific cable or device that can help me out there. Google
is turning up hundreds of cables and filters, but I'd hate to just start
taking shots in the dark if someone out there knows what would work for me.
Re: Cable interference
Well, I must come back to the group with a humble 'duh' on my part.
I was going to try a higher quality s-video cable and I had a DVD playing at
the time. I reached behind the player and found an s-video cable still
plugged in. This wasn't so much of a surprise since I had the s-video cable
going to my TV for when I didn't use the projector. What WAS a surprise was
when I unplugged the cable the video showing on the projector instantly got
about 25% brighter and was perfect. The band has gone away and I've got a
measurable increase in video quality.
This may be obvious to some, but I would guess at this point that since the
component and s-video outputs use some of the same electronics in the DVD
player (I'm guessing that since I have to choose between them in the
player's menu). I'm guessing that because of that, simply having both
cables plugged in at the same time causes issue with the video signal being
sent out of the player.
No need of a filter I guess, just more education on my part for the hook up.
Thanks for the brain time everyone, sorry to waste your time.
Re: Cable interference
Shawn Wilson wrote:
Though I didn't respond to your thread, take solace in knowing that you
found the problem and that it was simple enough to not be able to see the
forest through the trees for awhile.
It isn't a waste of anyone's time, but rather a good reminder to all to look
at the more simple things first. There are many of us that have gone
through similar scenarios and I'll be the first one to admit it!
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