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RGBHV over shielded Cat 5 success!

381K views 523 replies 230 participants last post by  djexit 
#1 ·
I am currently typing this message using a 25ft shielded cat 5 Ethernet cable. The image is extremely clear noticeably better than my 30 foot bundled coax that I normally use. To make the test more difficult, the Cat 5 cable is actually two separate pieces with a junction box 6 feet away from my monitor. This will be the cable that I will use as my HT redesign reaches final completion.


The idea actually came from Thumper. Dismayed by the price of plenum or standard rated coax cable and video amplifiers for his installed, he started tinkering with the idea of using Ethernet cable to run his video signals. He shared his success with me


He told me that I could get good results with standard Cat 5E cable and outstanding results with shielded Cat 5.


Well, premade shielded Cat 5 cables are a little hard to come by so I first tried the experiment using unshielded cat 5. I bought a 25 footer cut it into two 6 foot and 19 foot section and put an HD-15 on each of the cut ends. I then put an in-line Ethernet splicer to join the two Ethernet ends (explain latter). This yielded a long HD-15 to HD-15 cable.


Well the results with this cable where far from stunning. I got plenty of ringing and blurring at most frequencies including really bad results at 60 Hz.


I explained my results to Thumper and he told me to redo it with shielded Cat 5. I was very skeptical because I wasn't having a noise problem but ringing (i.e. impedance mismatch) problem instead.


That's when it hit me; general Cat 5 is 100 ohm twisted pair; however, with the shield tied to ground on the shielded version this would help lower the impedance to closer to video's 75 ohm requirement. I decided to give it another try.


The construction details:


The only local place I could find shielded Cat 5 products was at Fry's. L-com has them but they are mail order and a little more expensive.


I did the exact same thing as before. I bought a 25 foot shielded cat 5 cable and cut it into a 6 foot and 19 foot piece. I also bought a shielded Cat 5 junction box, two HD-15 male solder cup plugs and to 9-pin metal hoods (HD-15 is the same size). I wired the HD-15's in the following fashion to the shielded cat 5 cable.


HD-15 pin Cat 5 color

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

1. Red + Orange

2. Green + Green

3. Blue + Blue

4.

5.

6. Red - (aka GND) Orange stripe

7. Green - (GND) Green stripe

8. Blue - (GND) Blue stripe

9.

10. Ground (GND) shield wire.

11.

12.

13. H sync Brown

14. V sync Brown stripe

15.


The "-" signals are actually the very same ground as "Ground" is. The H and V don't need their own separate ground line. The results were excellent as I stated before.


At this point you might be saying cool but what does shielded Cat 5 give me over bundled coax? It gives a few things:


1. Thinner form factor.

2. Cheaper cable. Plenum being much cheaper

3. Much easier to solder to an HD-15 connector. Bundled coax requires shield terminators when soldering and big mouth back shells to allow the larger diameter of the cable to exit.

4. similarly, no break-out BNC to HD-15 cables required. These bring their own problems


and my favorite,


5. It allows me to manually switch four RGB sources between 2 displays. This would normally require a matrix switcher which is usually $1000+. To do this, I have two Ethernet jacks (one for my UP-1100 and one for my Princeton Graphics monitor) and four cables (HTPC, AccessDTV, Digital cable and Dreamcast) that go in in any configuration that I want.


All of this with an outstanding video quality to boot. This is really cool.


Thanks Thumper,


-Mr. Wigggles


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

The Mothership is now boarding.


[This message has been edited by MrWigggles (edited 06-12-2001).]
 
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#377 ·
Whew...what a read. Ok, I've gone through this entire thread and I have a few questions.


1) I'm about to wire my home computer network with CAT6 cable and I was wondering if this cable is ok to use for carrying the video signal to my projector. Everyone has pretty much discussed using CAT5/CAT5e in this thread.


2) If CAT6 is a viable choice, do I still need to look for STP? Or does CAT6 contain enhanced shielding already?


Thanks.
 
#378 ·
You have to use shielded cat 5 and only some brands work well.


The secret is that the overall shield for the shielded twisted pair helps lower the effective impedance of the entire cable down to near 75 ohms.


Personally I would use Belden cable (7919A or 7929A). The cable I mentioned at the beginning of the thread (which I found at Fry's) is a little hard to come by.


Remember, try to keep the thing to a 35 feet or less due to Skew reasons from pair to pair. Belden also make a specific video nano-skew cable, 7987R, but they inexplicably left it at 100 ohms. I don't know how well it will work since it isn't 75 and there is no shield to help drop it to 75, but a tight 100 ohms (not 100 +/- 15 like most) might be good enough


-Mr. Wigggles
 
#382 ·
On longer runs, coax is expensive. Here are the numbers in regards to cost savings based on Intelix baluns:



Audio- cheaper to use Cat 5/baluns over 1000 feet

Coax- cheaper to use Cat 5/baluns over 350 feet

Audio & Video- cheaper to use Cat 5/baluns over 300 feet

VGA- cheaper to use Cat 5/baluns over 100 feet


And for the most part, these baluns are passive with no power required....
 
#383 ·
Thanks to all who have contacted me about this information
 
#384 ·
What about that balun that was for in wall installations with a wall plate. The one with screw terminals?


I can't find that one. I know there was info here somewhere.


-Ed
 
#385 ·

Quote:
Originally posted by kcautodoc
Question,


I have been trying to make a breakout cable from STP Cat 5 cable. I am trying to go from Component out on my DVD to VGA in on my projector. I have a Sharp M20X projector which actually has DVI input but came with a DVI to VGA cable.


I have read the Cat 5 success thread numerous times. I have seen the comments that it can't be done with a DVI input and I have seen the comments about Component not working over Cat 5. It appeared that Robert_S had some success with Component signals and you can but DVI to VGA cables and VGA to Component cables so I don't really see a reason why you cannot make a Component to VGA cable.


You may ask why I am not making a DVI to Component cable. Well the projector comes with a DVI to VGA cable and finding a DVI plug that I can solder onto seems to be nearly impossible. I am only looking for about 22' feet here, but for the price people want for the breakout cable or DVI to Component is insane.


Anyway, I am looking for help making a Component to VGA cable and I'm hoping someone out there can help me solve my problem. I have done the soldering (see below) and get a good picture (better than my S-video) but, the picture appears to only have the green component because the picture only has different shades of green. The blacks are much deeper and the picture seems to have better contrast with what I have now with the green only. This may just be the fact that Green and Blue are missing but I may be really close to getting an even better picture that I am now used to.


This is my setup for soldering.


VGA pins

1 Red

2 Green

3 Blue


6 Red ground

7 Green ground

8 Blue ground


I've only got three wires left (one twisted pair and the shielding wire)


Any suggestions would be greatly appreciated.


Richard

i have a sharp pg-m25x, did you get this to work?


//Micke (Sweden)
 
#386 ·

Quote:
Originally posted by Edwood
What about that balun that was for in wall installations with a wall plate. The one with screw terminals?


I can't find that one. I know there was info here somewhere.


-Ed


Anyone have a link for this?


I'd rather not spend so much money on a VGA Balun Cat 5 extender.


-Ed
 
#388 ·
That be the one. Thanks!!


How long a run could I do with Cat6 wiring do you think?


-Ed
 
#390 ·
cat 6 will not give you any more appreciable distance. the wire is the same. however the twist ratios are different so there is the possibility of seeing what looks like a misalignment.


All of htis is using SHIELDED cat 5. UTP will not work.
 
#391 ·
has anyone tried using this with an NVidia video card?

As far as I've read the only problem is how to make the composite synch signal.

I've found the following site
http://www.sput.nl/hardware/tv-x.html

which offers a very simple scheme that creates one composite synch signal from the HSynch(13) and VSynch(14) of the VGA RGB.


Here is the scheme
Code:
Code:
-VS ------------------------+
                             |
                             |
                         |  /
       +-----+           |/
 -HS --+ 3k3 +-----*-----|     BC 548 B
       +-----+     |     |\\
                   |     |  \\|
                   |        -|     +-----+
                   |         *-----+ 68  +----- -CS 0.3 Vpp
                   |         |     +-----+
                  +++       +++
                  | |       | |
                  | |       | |
                  +++       +++
                   |         |
 GND --------------*---------*----------------- GND
                  1k2       820
do you think that this can work?
 
#392 ·
Merry Christmas to all!!!


I finally found some time during the weekend and tried to make VGA to RGB-CSynch with my NVidia GeForce4 Ti4200.

My TV is Panasonic TX-29AS1P QuintrixF (29" CRT 4:3 50Hz SDTV) and I've connected it to the VGA output of the VC while I keep my PC monitor connected to the DVI output using a DVI-RGB dongle.

I can say that it's working... well I have some problems and I hope someone can help me with them.


I used a 5m STP cable wired in the following way:


VGA SCART

1 ----------------------------- 15

2 ----------------------------- 11

3 ----------------------------- 7

6 ----------------------------- 13

7 ----------------------------- 9

8 ----------------------------- 5

9 ----------- R1 -------------- 16

CS ----------------------------- 20


R1 = 100Ohm


After configuring PowerStrip to output 720x576i I got a pretty nice picture on the TV.


But now let's start with the problems though:

1.

The first thing that I saw was that my TV stopped showing any cable TV (connected to the RF input). On any channel I saw a scrambled (not synched) picture of my desktop and the sound of the selected channel !?!?!? First I worried that I've damaged the TV but then I disconnected the RGB cable and everything was back to normal. Then I tried other inputs - Composite or S-Video in the second SCART on the back and they worked fine either with the RGB cable connected or not. Now I'm very confused what's happening. I haven't connected anything to pin 8 (Audio/RGB switch/16:9) of the SCART so this should be OK.... but it isn't.

Do you have any idea what could be wrong? Do I have to wire pin 18 (Blanking ground) of the SCART to something? or is it just fine to leave it unconnected?.... btw I'll try connecting it later today to see if there is any difference


2.

The second problem is that the mouse pointer shown on the TV is bigger - in fact I think it's exactly double sized. This is not a big problem if it wasn't also that it actually points on a different place. And I mean a big difference. I'm sensing that it has something to do with the interlaced signal because the difference in the place where it points with the place where it's displayed increases when I move down the screen. And when it points exactly in the middle (289) it is just going off the TV screen. And I'm sure that it's not an overscan issue because everything else is in place. I even see my taskbar...if I put it on the secondary monitor.

Any ideas what can I do to fix this?


3.

Using PowerStrip I've almost managed to eliminate any underscan of the picture but I'm on the edge with the frequencies and there are still a little black bars on both left and right sides. If I try to increase the picture even more I lose synch


Any advices? What resolutions do you try and with what timings?

I'm asking this because I think that mine are pretty off the specs for PAL and this is disturbing me (not the TV for the moment)

here are my settings:

PowerStrip timing parameters:

720x576=720,80,16,112,576,35,5,47,14850,2062


Generic timing details for 720x576:

HFP=80 HSW=16 HBP=112 kHz=16 VFP=35 VSW=5 VBP=47 Hz=24


Linux modeline parameters:

"720x576" 14.850 720 800 816 928 576 611 616 663 interlace -hsync -vsync


4.

One thing that disturbs me is that I hear a very light high frequency buzz from the TV. And it changes when I change the Pixel Clock or the Scan rates. Can you tell where this comes from? And is it dangerous for the TV?


5.

The final problem (.... for the moment :) ) is about a strange blinking of the PC monitor when I start different applications. For example if I start PowerStrip, UltraMon, CompareIt! my monitor goes off for a sec and then is back on again. I suppose with PowerStrip and UltraMon it's OK - they are all about monitors but CompareIt! is a simple text processing application that compares text files and shows the differences. !?!??!

Any ideas?


Do you have or did you have similar problems?
 
#393 ·
I'm about to try to make this cable.


Projector VGA to VGA about 10m/30feet away...


I notice MrWigggles used a shielded cat5 junction box...


What i want to do is similar...


Run the cat5 STP from the projector on the roof, down to where the DVD player etc.. will sit.. My projector has VGA and component input via its HD15 connection, switchable by the menu...


For neatness and to make it easier to swap the connections, i want to run the cat5 STP from the projector to a RJ45 plate on the wall, then have a couple of STP patch leads made up that go RJ45 VGA and RJ45 Component... and plug in which ever i'm using....


Problem is i can't find a Shielded RJ45 wall plate - I'm in Australia so would be much better if i could find one locally? If they are only available in the USA i have friends there i could get to mail me one...


EDIT:

Thinking about it some more, is it necesary to use STP for the RJ45 VGA and RJ45 Component leads to go from the wall plate to the source? Could i use UTP? (Do i need to pass the ground/shield line from the source to the STP run... to the projector? or is it enough having the STP ground wire running the 30feet from the projector to the wall plate mounted near the source DVD player etc..?)
 
#394 ·
Ran the cable from projector to source units, ran 3 lots of STP from my projector


1 for Composite

1 for SVID

1 for VGA/Component (15HD)


Wired up the VGA last night, plugged laptop in, perfect, no ghosting as far as i could see, only using 800x600 res... Wired the ground to pin 10 as Mr Wiggles said, didn't need to short the (-)'s to the ground pin....


Next steps are to wire the SVid and Composite, should be easy right?


Pin 1 = Y gnd (Use Green/White)

Pin 2 = C gnd (Use Orange/White)

Pin 3 = Y (Use Green)

Pin 4 = C (Use Orange)


And Composite just use 1 of the pairs, say green for the centre prong and greenwhite for the ground/outside...



And I'd still like to get my hand on a shielded RJ45 wall plate....
 
#397 ·
I've also read THumpers original response :


[To crank up the performance yet another notch, solder all the "grounds" and shield together (inside the shells) at both ends even though the video card & projector combine these grounds on their circuit boards.]


a few times and i'm not sure if he means don't bother soldering the (-)'s/grounds to the pins 6,7,8 and just solder them all to pin 10, or if he means solder them to pins 6,7,8 AND jumper them to pin 10, so pin 10,6,7,8 all connect


I'm assuming the 2nd option of jumpering 6,7,8,10 together


My laptop gives me no ghost as far as i can see, but plugging a VGA->component breakout lead to my xbox gives me a tiny ghost i think... so not sure if this will help... The XBOX is 2 prong power plug, ie no earth, so thinking anything without an earth socket may end up causing a bit of ghosting...
 
#398 ·
ferni,

its a coupler. That means it will take an RJ45 plug into both ends and it will transfer all 8 pins straight through. Also for your second question the shielding is passed by the sheild of the jack ( the metal that the jack is wrapped in).


As for the ends i used a solderless connector but did connect all grounds and it worked great. I did not compare the two versions
 
#399 ·
Thanks for that Ken,


I know what a coupler is... the shielding I've never worked with before hence the silly questions... So the shield wire is connected to the RJ45 plug itself which its metal not plastic?and that passes through the 9th wire (shield?)


When you say you did connect all grounds, did you solder them to each other AND the 6,7,8,10 pins? or just solder them together and then to pin 10?


I've also found that when my xbox is on connected via component breakout lead to my projector, the TV gets interference, as soon as I disconnect the xbox video cable (or turn the xbox off) the interference disappears... Xbox is 2 prong power plug, i.e. no earth, so thinking connecting pins 6,7,8,10 together may help...
 
#401 ·
hello there MrWigggles, i was curious about your experiment here, i want to know if there any possibilities from using the cat 5 cables to connect the vga connector (male) to the component cables (Y Pb Pr), because i want to connect the pc to the plasma/lcd tv at component in or opposite from it from dvd player component out to the vga in at the plasma/ lcd tv, and could you tell me how to do it and the schematics/diagram for rigging it, and one thing please send me the picture to explain the installation for the cat 5 cable at my email : svetlana12ax7@yahoo.com


best regards,

svetlana
 
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