Trying to go from one computer to 10 LCD TV's...

D

Dillusion

Supreme [H]ardness
Joined
Oct 21, 2003
Messages
5,465
...but the problem is they are all coaxial. I have a business which has 10 LCD/plasma TVs in it. I need to hook up a computer in my back junction room where all the coax cables end so I can play powerpoints and videos from online over these TVs on a channel.

I used to be able to do this VIA an old old RF Adapter which put the stuff on channel 112 somehow and it worked fine from a DVD player with one yellow RCA plug.

Now, I have this computer with a VGA out. I got a VGA to yellow RCA adapter, and it's connected to a radio shack RF converter on channel three with a coaxial out to my TV junction box, but when the TV's are put on channel 3, the image is scrambled and unable to be seen.

When a digital broadband amplifier is attached, the image is scrambled, but can sort-of be seen. I'm assuming the digital amp is broken but theyre expensive...

Is there another way or better way to go from one VGA to multiple coax outs?
 
Disclaimer:

I links in this post are not meant to recc specific hardware, just give you an idea of what types of equipment to look for. It would take hours to research the proper equipment and narrow down brands and that would be highly based on budget considerations.


You need a scan converter to take your vga signal and convert it to a composite NTSC video signal (yellow rca). The scan converter will allow you to adjust the scaling and edges etc in addition to just converting the signal. Usually professional scan converters will have a professional BNC connector for video out, not an rca. The good news is that you can get a BNC to rca adapter for a few dollars (scan converters run from a few hundred to 8000+ on up to who knows. We use folsom image pro hd units in our remote hd control rooms, but those are around 8k each and you don't need HD-SDI output (or even regular SD-SDI for that matter). FYI: SDI stands for serial digital interface, but you don't need that since your coax inputs on the TVs are analog only.

Basic scan converter with good quality (look for folsom, kramer, gefen, extron etc):
http://www.bhphotovideo.com/c/produ...01XL_VP_501XL_Scan_Converter.html#accessories


Do you have your old RF adapter still? If you could pick up a scan converter, you should be able to feed that composite video signal into your old adapter onto channel 112. Please note that composite video signal and a typical cable signal are different things, although you can send composite video into a coax cable if you adapt the ends to rca and that is all you are sending.

RF Modulator (low grade consumer unit):
http://radioshack.com/product/index.jsp?productId=2103095

RF DA (high quality, you need to find one with more outs or loop 2-3 together)
http://www.bhphotovideo.com/c/product/244195-REG/Kramer_104R_104R_1x4_RF_Distribution.html


Please note that composite video (yellow rca) is not even 480 approximate lines of resolution in the best case (IE 640x480) NTSC TV when recorded onto DV tape is only 720x480 (equivalent to 640x480 when you factor in that DV uses non-square pixels). Whatever power computer signal you feed the monitors will be very low res (not even factoring in line loss from running down a long cable or splitting the signal.

Another Option:

Do the TVs have vga in? If so you could break out your vga signal to rgvhv (5 wire) with cheap fan outs and get an rgbhv (5 wire) distribution amplifier. You could take a long run with 5 wire cable to each tv and have little if any line loss due to the nature of the cables (and convert back to vga at the tv end. You could also maintain a much higher resolution such as 1280x720 @59 or 60Hz (3x the number of pixels over 640x480). That should work much better as it is the native aspect ratio and much closer to the native resolution of the tv sets.

RGBHV fanout here:
http://www.bluejeanscable.com/store/rgbhv/index.htm

RGBHV DA here:
http://www.extron.com/product/product.aspx?id=da6rgbhv&subtype=287&s=4

You could also go for a vga da and then just fan out the outputs to 5 wire before the long run to the tvs. You can't do standard vga cable past 100', you have to fan it out to 5 wire.

Avoid going 1080 as I doubt that your tvs actually have more than 1280x720, 1280x768 or 1366x768 native res anyway. I always try to work in 720p wherever possible and avoid 1080i due to lower vertical resolution with the interlaced signal that only displays 1 field at a time (so it is actually 540 lines not 1080 lines like you are lead to believe). If you were working from a vga signal, this is not really the case as computer signals are progressive, but I would still stay away from 1080 as 720p is plenty sharp and a huge step up from what you have now.
 
Last edited:
Would another broadband digital amplifier help? Or is the signal VGA coming from the computer not directly compatible with the RF converter? Does it need to be first converter by the scan converter before it hits the RF adapter?
 
You must log in or register to reply here.
Back
Top