Using RG-6 cable for analog video.

Thread Starter

MisterBill2

Joined Jan 23, 2018
11,876
I have a possible application of needing to feed a video projector with an analog video signal. I would use a VGA cable except the cost and effort of installation are rather huge. I already have the module to convert VGA to analog composite video, I am wondering about how well it would work with a length of about 150 feet to the projector. Both the source and the projector ports are 75 ohms, as is the RG-6 cable, but I am concerned about losses and the frequency response, and the effect on the video. Does anybody have any experience in this area??
 

Papabravo

Joined Feb 24, 2006
18,400
You should be able to find a datasheet for the cable which will quantify the things you are looking for. I'm not sure what your video source is producing, but a baseband TV signal occupies about 6MHz of bandwidth. I can't think of a reason for upconverting the baseband signal to a standard VHF or UHF frequency since those channels are no longer used for over the air transmission. More details on the video source would be helpful. In amateur radio applications several hundred feet of coax can be used up to about 50 MHz or so. For higher frequencies like 1296 MHz. we often use 7/8" hardline which can be pricey, but at least it reduces the transmission losses.
 

crutschow

Joined Mar 14, 2008
29,772
According to thus, there should be no problem, as the bandwidth of composite video is only about 6MHz.

So the projector is just standard definition?

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Last edited:

nsaspook

Joined Aug 27, 2009
9,717
Yes, I've use RG-6 and RG-59 for 75 ohm long video cables. RG-6 quad shield easily handles HI-DEF analog 30MHz video streams.

This projector uses three RG-6 quad shield cables for a 50 foot component video feed.


For this projected image from a high def analog source feed.

 

Thread Starter

MisterBill2

Joined Jan 23, 2018
11,876
@ nsaspook, THANKS, that is the sort of information I was looking for. My cable run will be quite a bit longer, but if your installation worked out then mine has a good chance of working also. Quite encouraging indeed.
 

nsaspook

Joined Aug 27, 2009
9,717
@ nsaspook, THANKS, that is the sort of information I was looking for. My cable run will be quite a bit longer, but if your installation worked out then mine has a good chance of working also. Quite encouraging indeed.
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https://www.cableandwireshop.com/rg-6-quad-shield-cable.html
Try to get cable with a solid copper center conductor. Most of the big box stuff is copper plated iron. I've used the plated stuff before but it's higher loss and stiff as hell.

It will work fine if the video source line output has sufficient drive capacity (most consumer devices are not designed to drive long cables). I used a RGB video switcher with a built-in Video Distribution Amplifier.
You might want to have a DA handy if the signal levels on the receive side are marginal.
https://www.bhphotovideo.com/c/product/765351-REG/Shinybow_sb_3701bnc_1_To_4_Video.html/overview

https://www.bhphotovideo.com/c/buy/Distribution-Amplifiers-DA-S/ci/16663
 
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Thread Starter

MisterBill2

Joined Jan 23, 2018
11,876
I have half of a 500 foot spool of the Belden brand cable, I would try that first.I think it will be long enough. I really want to avoid any splices because they would be done with "F" connectors, not my favorite connector.
 
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