Picture gets blurry when using VGA splitter


Z

ZalekBloom

Hello,
I purchased HDTV with VGA input entry and decided to have option to
connect it to my PC.
I bought VGA splitter and connect it to my PC.
This is a simple draw what I did:
http://www.geocities.com/zalekbloom/pictures/vga_connect.jpg

Here is what happend:
after I connected VGA splitter to PC and a PC monitor to a splitter -
picture on PC monitor was OK.
The moment I connected a second cable to a splitter (the one that goes
to HDTV, nr 2 on the picture) - the picture on a PC monitor became
very blurry. I made few tests - the picture on the PC monitor became
blurry even when the connected cable was not connected to the HDTV.
When PC is connected to a monitor through the splitter - picture on
the monitor is OK.
My question - why and how to solve this problem?

Thanks,

Zalek
 
Ad

Advertisements

R

Richard Crowley

Hello,
I purchased HDTV with VGA input entry and decided to have option to
connect it to my PC.
I bought VGA splitter and connect it to my PC.
This is a simple draw what I did:
http://www.geocities.com/zalekbloom/pictures/vga_connect.jpg

Here is what happend:
after I connected VGA splitter to PC and a PC monitor to a splitter -
picture on PC monitor was OK.
The moment I connected a second cable to a splitter (the one that goes
to HDTV, nr 2 on the picture) - the picture on a PC monitor became
very blurry. I made few tests - the picture on the PC monitor became
blurry even when the connected cable was not connected to the HDTV.
When PC is connected to a monitor through the splitter - picture on
the monitor is OK.
My question - why and how to solve this problem?
Since you said nothing about what this "VGA splitter" is,
it is difficult to offer any definite advice. If you want to
actually explain what it is, we can likely help you.

If this "VGA splitter" is merely a Y-cable with three
connectors, throw it away and get a proper powered
distibution amplifier. If your "VGA splitter" is already
a powered distribution amplifier, then you need a
better one.

You simply cannot "split" a video signal with a passive
cable. Not if you wish to retain any quality, at least.
Also, the larger the screen, the more you can see any
problems with the video signal, so the more critical to
use quality devices/cable, etc. in the complete path.

In the absense of the critical info, here are some general
suggestions...
Use better quality cable(s).
Keep the cable(s) as short as possible.
The longer the cable, the more critical it is good quality.
Avoid any "splices"/"adapters", etc.
Use better quality distribution amplifier.
 
Z

ZalekBloom

Since you said nothing about what this "VGA splitter" is,
it is difficult to offer any definite advice. If you want to
actually explain what it is, we can likely help you.

If this "VGA splitter" is merely a Y-cable with three
connectors, throw it away and get a proper powered
distibution amplifier. If your "VGA splitter" is already
a powered distribution amplifier, then you need a
better one.
My VGA splitter is a simple Y-cable - this is the one I purcheased:

http://www.cablesdirect.com/prodimages/CC320Y_LR.jpg
You simply cannot "split" a video signal with a passive
cable. Not if you wish to retain any quality, at least.
Also, the larger the screen, the more you can see any
problems with the video signal, so the more critical to
use quality devices/cable, etc. in the complete path.

In the absense of the critical info, here are some general
suggestions...
Use better quality cable(s).
Keep the cable(s) as short as possible.
Well - the distance between PC and the HDTV is not small - about 30
feet. As matter of fact my project is more complicated - I need to
connect 2 PCs to HDTV, but first I want to solve the "blurryeness"
problem.
This is the full project:
http://www.geocities.com/zalekbloom/pictures/tv-connection.JPG
The longer the cable, the more critical it is good quality.
Avoid any "splices"/"adapters", etc.
Use better quality distribution amplifier.
This is tha cable I am using in my project:
http://www.cablesdirect.com/prodimages/CC388A1-10_LR.jpg
It says about the cable:
" 35ft Premium Tri-Shield VGA HD15 & 3.5mm Stereo Male to Male Combo
Cable, Connects any VGA video with audio to any computer, switch or
splitter with HD15/3.5mm stereo female ports. This premium combo cable
eliminates clutter and improves cable management. Supports all VGA
monitors including analog flat panel display, high resolution desktop,
CAD and graphic workstations. It has color-coded connectors for
error-free hook-up, triple shielding for maximum graphics performance,
prevents signal loss, screen ghosting & loss of color and works up to
200ft without a signal booster. Pin #9 is removed for universal VGA
compatibility. This cable have matched impedance, PVC jacket, molded
ends with thumbscrews and inner hood soldered 360 degrees to the
connector for complete end to end shielding. Note: The stereo audio
cable is 15inch on both ends. (Connectors: HD15/3.5mm Male to Male;
Length: 35ft)".

Can suggest a VGA amplifier? How I should connect it?

Thanks,

Zalek
 
R

Richard Crowley

My VGA splitter is a simple Y-cable - this is the one I purcheased:
http://www.cablesdirect.com/prodimages/CC320Y_LR.jpg
That gadget is a rip-off (IMHO) and is unsuitable for any
but the most non-critical application. Some people think
they shoud be illegal to sell. For the very reason you have
discovered first-hand. What you are seeing is completely
predictable from trying to use such a gadget. Hopefully you
can return it for a refund.

You cannot "split" video like you can do with audio or RF.
Video must have a single 75-ohm load at the destination end.
That kind of "Y-cable" puts TWO 75-ohm loads at the (multiple)
ends, for a total of 37.5 ohms. That cuts your video in half
all by itself, without also addressing the problem of multiple
loads at different distances which is another source of your
"blurry" video performance (multiple reflections from improper
loading).
You can try cheaping it out with "Y-cable splitters"
and inexpensive selector switches, I would likely try
it myself. But don't be surprised to find significantly
degraded video quality unless you use better-quality
equipment in the video path. High-resolution video
from computers is very much higher bandwidth than
simple TV video and requires more serious ($$$)
solutions to maintain the desired quality, particulary
when viewing it on a big screen.
That cable may be suitable, given a proper source.
What happens if you plug that cable directly into
your computer? If it looks good there, then your
problem is the splitter and not the cable.
Can suggest a VGA amplifier?
Many people sell VGA amplifiers for a wide variety of
prices. Radio Shack may even have them for all I know.
Here are a couple (watch out for line-wrap)...

http://www.partsexpress.com/pe/pshowdetl.cfm?&Partnumber=183-670&CFID=42050&CFTOKEN=11613969

http://www.markertek.com/SearchProduct.asp?item=TV1-VGA201P&off=0&sort=prod

Markertek has a whole bunch of them. The one above is just
the first one in the list (and the cheapest). I would bet that
it would solve your problem.

There are many currently up for bid (or BuyItNow) on eBay.
For example: eBay# 220068126159 Even one of those
things at $12.45 is infinitely better than your "Y-cable".
I might just buy one or two of those myself, They seem
reasonable to me.
How I should connect it?
They all have 1 input and two or more outputs. You can
figure out how to hook them up just by looking at them.
You would plug the output from your computer into the
input of the VGA amplifier, and then each of the amplifier
outputs to the corresponding destination.

You may also find a "matrix switch" that would route your
various inputs to your various outputs and will take care of
the distribution amplification problem all in one box. But
likely not cheap except maybe on eBay.
 
J

J Brockley

Hello,
I purchased HDTV with VGA input entry and decided to have option to
connect it to my PC.
I bought VGA splitter and connect it to my PC.
This is a simple draw what I did:
http://www.geocities.com/zalekbloom/pictures/vga_connect.jpg

Here is what happend:
after I connected VGA splitter to PC and a PC monitor to a splitter -
picture on PC monitor was OK.
The moment I connected a second cable to a splitter (the one that goes
to HDTV, nr 2 on the picture) - the picture on a PC monitor became
very blurry. I made few tests - the picture on the PC monitor became
blurry even when the connected cable was not connected to the HDTV.
When PC is connected to a monitor through the splitter - picture on
the monitor is OK.
My question - why and how to solve this problem?

Thanks,

Zalek
VGA is an uncompressed format i.e. several 10s of mhz unlike component,
svideo etc. Because of this poor quality cable or excessive length is going
to be a severe problem. With the splitter you are using even an unterminated
cable will still be putting on a capacitive load effectively knocking out
the high frequencies. This would lead to the effect you are seeing. I
suspect the only way this splitter is going to work at all is by using very
short cable lengths.
 
F

Franc Zabkar

My VGA splitter is a simple Y-cable - this is the one I purcheased:

http://www.cablesdirect.com/prodimages/CC320Y_LR.jpg


Well - the distance between PC and the HDTV is not small - about 30
feet. As matter of fact my project is more complicated - I need to
connect 2 PCs to HDTV, but first I want to solve the "blurryeness"
problem.
This is the full project:
http://www.geocities.com/zalekbloom/pictures/tv-connection.JPG


This is tha cable I am using in my project:
http://www.cablesdirect.com/prodimages/CC388A1-10_LR.jpg
It says about the cable:
" 35ft Premium Tri-Shield VGA HD15 & 3.5mm Stereo Male to Male Combo
Cable, Connects any VGA video with audio to any computer, switch or
splitter with HD15/3.5mm stereo female ports. This premium combo cable
eliminates clutter and improves cable management. Supports all VGA
monitors including analog flat panel display, high resolution desktop,
CAD and graphic workstations. It has color-coded connectors for
error-free hook-up, triple shielding for maximum graphics performance,
prevents signal loss, screen ghosting & loss of color and works up to
200ft without a signal booster. Pin #9 is removed for universal VGA
compatibility. This cable have matched impedance, PVC jacket, molded
ends with thumbscrews and inner hood soldered 360 degrees to the
connector for complete end to end shielding. Note: The stereo audio
cable is 15inch on both ends. (Connectors: HD15/3.5mm Male to Male;
Length: 35ft)".

Can suggest a VGA amplifier? How I should connect it?

Thanks,

Zalek
It looks like the problem is with your Y-adapter. What you are
effectively doing is terminating your 75 ohm source with a 37.5 ohm
impedance (2 x 75 ohm devices in parallel). This results in
reflections (ghosting) and a reduction in signal amplitude.

The way that multiple studio monitors are connected is by daisy
chaining them and terminating only the last monitor in the chain. All
other monitors have their 75 ohm terminations switched off. If you are
willing to hack your monitor, you might try to disconnect the internal
75 ohm resistors. Otherwise purchase a distribution amp as suggested
elsewhere in this thread.

- Franc Zabkar
 
Ad

Advertisements

Z

ZalekBloom

That gadget is a rip-off (IMHO) and is unsuitable for any
but the most non-critical application. Some people think
they shoud be illegal to sell. For the very reason you have
discovered first-hand. What you are seeing is completely
predictable from trying to use such a gadget. Hopefully you
can return it for a refund.

You cannot "split" video like you can do with audio or RF.
Video must have a single 75-ohm load at the destination end.
That kind of "Y-cable" puts TWO 75-ohm loads at the (multiple)
ends, for a total of 37.5 ohms. That cuts your video in half
all by itself, without also addressing the problem of multiple
loads at different distances which is another source of your
"blurry" video performance (multiple reflections from improper
loading).


You can try cheaping it out with "Y-cable splitters"
and inexpensive selector switches, I would likely try
it myself. But don't be surprised to find significantly
degraded video quality unless you use better-quality
equipment in the video path. High-resolution video
from computers is very much higher bandwidth than
simple TV video and requires more serious ($$$)
solutions to maintain the desired quality, particulary
when viewing it on a big screen.


That cable may be suitable, given a proper source.
What happens if you plug that cable directly into
your computer? If it looks good there, then your
problem is the splitter and not the cable.


Many people sell VGA amplifiers for a wide variety of
prices. Radio Shack may even have them for all I know.
Here are a couple (watch out for line-wrap)...

http://www.partsexpress.com/pe/pshowdetl.cfm?&Partnumber=183-670&CFID=42050&CFTOKEN=11613969

http://www.markertek.com/SearchProduct.asp?item=TV1-VGA201P&off=0&sort=prod

Markertek has a whole bunch of them. The one above is just
the first one in the list (and the cheapest). I would bet that
it would solve your problem.

There are many currently up for bid (or BuyItNow) on eBay.
For example: eBay# 220068126159 Even one of those
things at $12.45 is infinitely better than your "Y-cable".
I might just buy one or two of those myself, They seem
reasonable to me.


They all have 1 input and two or more outputs. You can
figure out how to hook them up just by looking at them.
You would plug the output from your computer into the
input of the VGA amplifier, and then each of the amplifier
outputs to the corresponding destination.

You may also find a "matrix switch" that would route your
various inputs to your various outputs and will take care of
the distribution amplification problem all in one box. But
likely not cheap except maybe on eBay.
Richard,

Thanks for your help. I ordered 2 VGA splitters from ebay - hope it
will work.
After receiving and installing it I will inform you guys about
results.
Thanks again for your help,

Zalek
 
D

Darkknight

Richard said:
Since you said nothing about what this "VGA splitter" is,
it is difficult to offer any definite advice. If you want to
actually explain what it is, we can likely help you.

If this "VGA splitter" is merely a Y-cable with three
connectors, throw it away and get a proper powered
distibution amplifier. If your "VGA splitter" is already
a powered distribution amplifier, then you need a
better one.

You simply cannot "split" a video signal with a passive
cable. Not if you wish to retain any quality, at least.
Also, the larger the screen, the more you can see any
problems with the video signal, so the more critical to
use quality devices/cable, etc. in the complete path.

In the absense of the critical info, here are some general
suggestions...
Use better quality cable(s).
Keep the cable(s) as short as possible.
The longer the cable, the more critical it is good quality.
Avoid any "splices"/"adapters", etc.
Use better quality distribution amplifier.
what he said!
 
M

Mike Ruskai

Hello,
I purchased HDTV with VGA input entry and decided to have option to
connect it to my PC.
I bought VGA splitter and connect it to my PC.
This is a simple draw what I did:
http://www.geocities.com/zalekbloom/pictures/vga_connect.jpg

Here is what happend:
after I connected VGA splitter to PC and a PC monitor to a splitter -
picture on PC monitor was OK.
The moment I connected a second cable to a splitter (the one that goes
to HDTV, nr 2 on the picture) - the picture on a PC monitor became
very blurry. I made few tests - the picture on the PC monitor became
blurry even when the connected cable was not connected to the HDTV.
When PC is connected to a monitor through the splitter - picture on
the monitor is OK.
My question - why and how to solve this problem?
Get a graphics card with two outputs, and toss the splitter.
 
G

GMAN

Richard,

Thanks for your help. I ordered 2 VGA splitters from ebay - hope it
will work.
After receiving and installing it I will inform you guys about
results.
Thanks again for your help,

Zalek
Youd be much better off getting a late model NVIDIA or ATI video card that has
dual heads. Almost all modern video cards have two outputs, a VGA and a DVI
connector that can be used with simple $5 adapter to use as a second VGA
connection.
 
Z

ZalekBloom

Since you said nothing about what this "VGA splitter" is,
it is difficult to offer any definite advice. If you want to
actually explain what it is, we can likely help you.

If this "VGA splitter" is merely a Y-cable with three
connectors, throw it away and get a proper powered
distibution amplifier. If your "VGA splitter" is already
a powered distribution amplifier, then you need a
better one.

You simply cannot "split" a video signal with a passive
cable. Not if you wish to retain any quality, at least.
Also, the larger the screen, the more you can see any
problems with the video signal, so the more critical to
use quality devices/cable, etc. in the complete path.

In the absense of the critical info, here are some general
suggestions...
Use better quality cable(s).
Keep the cable(s) as short as possible.
The longer the cable, the more critical it is good quality.
Avoid any "splices"/"adapters", etc.
Use better quality distribution amplifier.
Well - I tried to do it cheap (I paid $40 for 2 splitters incl
shipping) and as usually I am going to pay more...

I purchased electronic 2 port video splitter PCI PC1400 400MHz and
used it instead of my Y - cable. When I connect the VGA output to TV -
the monitor picture still gets blurry, although not as bad as with the
Y cable. But I notice another strange thing - while picture on the PC
monitor look normal, the picture on the HDTV looks normal only in DOS
screen or Win in a stretched mode, here are pictures I took:

while in DOS regular mode:
http://www.geocities.com/bloomzalek/pictures/HDTV_DOS_regular.jpg

while in DOS i stretched mode
http://www.geocities.com/bloomzalek/pictures/HDTV_DOS_stretched.jpg

while in Win regular mode:
http://www.geocities.com/bloomzalek/pictures/HDTV_Win_regular.jpg

while in Win i stretched mode
http://www.geocities.com/bloomzalek/pictures/HDTV_Win_stretched.jpg

Any ideas why picture in Win regular mode is showed this way on HDTV,
while on a PC monitor it looks normal?

Thanks,

Zalek
 
Ad

Advertisements

G

Gene E. Bloch

Well - I tried to do it cheap (I paid $40 for 2 splitters incl
shipping) and as usually I am going to pay more...

I purchased electronic 2 port video splitter PCI PC1400 400MHz and
used it instead of my Y - cable. When I connect the VGA output to TV -
the monitor picture still gets blurry, although not as bad as with the
Y cable. But I notice another strange thing - while picture on the PC
monitor look normal, the picture on the HDTV looks normal only in DOS
screen or Win in a stretched mode, here are pictures I took:

while in DOS regular mode:
http://www.geocities.com/bloomzalek/pictures/HDTV_DOS_regular.jpg

while in DOS i stretched mode
http://www.geocities.com/bloomzalek/pictures/HDTV_DOS_stretched.jpg

while in Win regular mode:
http://www.geocities.com/bloomzalek/pictures/HDTV_Win_regular.jpg

while in Win i stretched mode
http://www.geocities.com/bloomzalek/pictures/HDTV_Win_stretched.jpg

Any ideas why picture in Win regular mode is showed this way on HDTV,
while on a PC monitor it looks normal?

Thanks,

Zalek
Perhaps that is using a video mode that your HDTV can't display.

My TV's manual has a chart near the back giving the supported
resolutions - I definitely needed it in order to get my system going
OK.

Now wait for a reply from someone who actually knows :)
 
Ad

Advertisements

R

Richard Crowley

Well - I tried to do it cheap (I paid $40 for 2 splitters incl
shipping) and as usually I am going to pay more...

I purchased electronic 2 port video splitter PCI PC1400 400MHz and
used it instead of my Y - cable. When I connect the VGA output to TV -
the monitor picture still gets blurry, although not as bad as with the
Y cable. But I notice another strange thing - while picture on the PC
monitor look normal, the picture on the HDTV looks normal only in DOS
screen or Win in a stretched mode, here are pictures I took:
One problem at a time. We assumed before that your
TV actually works properly with computer video input.

What makes you think your TV is not broken? Have
you EVER seen a good picture out of it with the computer
2 feet away and connected directly?
 

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments. After that, you can post your question and our members will help you out.

Ask a Question

Top