VGA cable (component signal) interference

Have a question or want to start a discussion? Post it! No Registration Necessary.  Now with pictures!

Threaded View


I have a projector home theatre setup and I am seeing a wide lighter band
roll from bottom to top in my video signal.  The color in that band is
preserved, just lighter.  Much like dark scan lines of a CRT when
videotaped, but slow (takes several seconds to pass by) and light instead of
dark.  I know what causes the CRT lines, no need to go into that... and I'm
pretty sure I know what's causing my lines (in theory).  But how can I clean
it up?  Can I buy a device to clean that up or do I have to get a better
cable?  If I have to get a better cable, then how do I know what's a 'good'
cable, the one I have says it's quite well shielded...  I'm assuming that my
problem is caused by interference in my area, but what should I do about it?
The lines aren't 'horrible' but they are distracting in dark scenes.

Things of note:  When I use a short video cable, there is no band.  Whether
I use a long s-video cable or a VGA cable makes no difference, the band is
there with both long cables.  The cables in question are 50ft long (s-video
is actually two 25ft cables connected together).  If I use the 50ft cables,
yet curl them up 5 ft from the video source there is no band.  Only when
stretched out to length is there a band.

I have a Sanyo DVD player and I'm using the component outputs to send video
to my projector (Dell 2300MP).  The projector doesn't have component inputs
per se, it uses the VGA input to carry that signal and I presume the
electronics sort it out inside.  The projector shipped with a cable with
component plugs on one end and a vga connector on the other, I'm plugging in
my VGA extension into that.

As anyone with a projector probably knows, the projector is a ways away from
the DVD player and I purchased a 50ft VGA cable to do the job from Dell with
the projector.  ($50, wasn't too bad)

(in case you want specifics)
http://accessories.us.dell.com/sna/ProductDetail.aspx?c=us&l=en&cs=555&sku=310-4729&category_id=5649

From their marketing blurb:
Constructed from high quality UL 2919 certified double-shielded (90% braid)
28AWG 75 Ohm coaxial conductors for the RGB signals, 28AWG 50 Ohm RG174/U
for the H-sync signal, 28 AWG twisted pair cable, and solid pins for maximum
durability, this cable features superior signal integrity design for minimal
signal distortion, loss and ghosting.

Is that information bloated or is it just not enough?

Thank you in advance!

--
Shawn Wilson




Re: VGA cable (component signal) interference



I can't stand Dell...

Acoustic Research makes excellent cables for great prices. I'd
recommend you look into that. Also make sure that your cables don't run
near any poorly shielded cables or flourescent lamps. There are also
some in-line devices you can install.


--
ebackhus

Old houses have fuses! My house is old!
------------------------------------------------------------------------
ebackhus's Profile: http://www.homeplot.com/member.php?userid=90
View this thread: http://www.homeplot.com/showthread.php?t=58393



Re: VGA cable (component signal) interference


Quoted text here. Click to load it

so what...  if you would have put some short comment about why, maybe there
would have been a point to you saying that, but either way it's off-topic
extra fodder.

That said... while I don't have any brand loyalty myself, I do have to say
that any company that gives me a 24hr PRE-ship replacement as part of the
standard warranty is good in my book.  Maybe PRE-ship replacements and 4
hour on-site response if they do have to come out just isn't good enough for
some people.

Maybe their 'home' segment isn't great, but I always buy from the business
side with on site support so even my phone calls are a breeze.  Take note:
mostly all Dell's 'home' staff are from Iraq (or wherever), while their
'business' staff are US based works on a rep system (so I always call Gary
to order, not a phone bank).  It's like dealing with 2 totally different
companies.

Quoted text here. Click to load it

Well thank you for trying I guess, the basic general suggestion was good.
But I asked if a device existed to put in-line to clean it up... and you
simply said 'yup'.

What, who, and where, was the expected information... maybe I should have
been more clear...

If such a device exists, then where might I get one?  And to be a little
more clear, a URL would be great - as a Google search for Acoustic Research
made for MANY results for example - none of which so far show a listing for
a 50ft VGA cable product made by AR (as my question pointed out would be my
need).

--
Shawn Wilson




Re: VGA cable (component signal) interference


The cable's probably fine. You've tried two different cables with the
same result. I don't think we're getting the whole story here. What is
that cable crossing in the 45 excess feet to the projector. Look around
for air conditioner, subwoofer, mini-fridge, or even the projector's
own power cord. Signal running parallel to power is baadddd. Get out
the stud finder and look at the wall that it runs along. You might have
to search out cable or sat.TV runs giving off interference, or it could
even be plumbing! Is there a guest bathroom nextdoor? just put the
projector on a rolling ottoman and start pulling back. The cable gets
unwound further and further, until you see the 'light bars'. Whevever
you're standing, that's where your problem is.



Re: VGA cable (component signal) interference


Quoted text here. Click to load it

Well, in the front of the room is my TV and stand, along with a DVD player,
DirecTV Tivo, cheap surround sound unit - all of which are off except the
sound during projector use.

I was running the cable next to the wall all the way which passed by my desk
and computer, but then I moved it to the center of the room.  I also moved
the cable at the front so it was not going by my little cheap sound unit.
Still have the line.

Here are some pictures if you want to see things.  (I just moved in so no
furniture, and shut up about the cat-5).  The pictures show how I first had
the cable run along the wall.  The video picture doesn't show the line... I
wasn't trying to get it at the time, but could if anyone wanted to see it
probably.

The signal cable you can see along the wall in pic 31, and the last of it
curled on the counter in front of the projector in pic 40.  Also in pic 40,
you can see the power cord going off to the right to the plug there in the
wall.

http://www.dvigroup.net/etc/share/pic/project/IMG_0031_sized.jpg

http://www.dvigroup.net/etc/share/pic/project/IMG_0040_sized.jpg

http://www.dvigroup.net/etc/share/pic/project/IMG_0018_sized.jpg

The reason I'm looking for a filter of some kind is that whater is causing
my lines is something out of my control it seems.

I am going to try using a UPS for power tonight just to rule out the power
itself - don't know if that makes sense, but I'm going to eliminate it
anyway.

--
Shawn Wilson




Re: VGA cable (component signal) interference


Shawn, the Dell extension won't cut it on this one. If AR or even
RadioShack(Gold) is making VGA in that length, snatch one up. That
being said, the real problem(which I don't think you can do much
about), is the location of your projector. Not only does the cable pass
right by the computer(hard-drive, power supply, etc.); but the
projector itself stands only a few feet from a refridgerator compressor
and a microwave oven. If you owned the place, you could someday mount
it in one of those wall cabinets and run the cable through the ductwork
that runs the length of the ceiling. That would most definately solve
the interference problem but you'd still have to get a new cable for
reasons of fire code! Good luck, my friend.



Re: VGA cable (component signal) interference


Quoted text here. Click to load it

Well, like I said, the cable was moved to the middle of the floor... and
during all of this the PC was off.

As for the projector in the kitchen (at least 6 feet in front of the
fridge), I should be able to un plug the fridge for a few minutes and see if
my problem goes away, right?  And would a microwave and fridge cause an
issue when neither are actually in use at the time? (meaning that the fridge
isn't 'pumping' at the time, just sitting idle)

In any case, I'm back to my initial question, do they make (and where would
I get one from) a device to filter such noise out?

I'd have no problem unplugging the fridge and microwave during a movie, and
I have the PC off already during a movie usually, but if I'm still left with
a problem then it's something outside of my appt (at least outside of my
control) and I'm still left looking for a filter.

Thanks for your input.

--
Shawn Wilson





Re: VGA cable (component signal) interference


Quoted text here. Click to load it

Interestingly enough, when the projector is showing it's own logo screen and
searching for a signal, there is no evidence of interference.  Only once the
video source is pulled in through a long cable does a problem show up.

--
Shawn Wilson




Re: VGA cable (component signal) 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.


--
Shawn Wilson




Re: VGA cable (component signal) interference




Shawn,

It looks like an apartment to me??? If so, it could be the guy above or

below is running a fan? frig? fluorescents? etc....In which case you'll

just have to invite him to all of your screenings...





--

yustr

------------------------------------------------------------------------

yustr's Profile: http://www.homeplot.com/member.php?userid=37

View this thread: http://www.homeplot.com/showthread.php?t=58393




Re: VGA cable (component signal) 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.


--
Shawn Wilson




Site Timeline