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Mic Cable vs Coax for Video? Reverb & Delay Plugins
Old 17th September 2011
  #1
Gear Nut
 

Mic Cable vs Coax for Video?

I am in the process of wiring up video cameras throughout the studio. I have been looking for information to determine if I need (or should) use Coax (like RG6) over a standard shielded mic cable.

A shielded mic cable will be easier to work with and also allow me to send the DC voltage to camera over the 2nd wire (and I have this in bulk already).

Would a RG coax and separate power wire be better?

I am running 4 cams to a 4 way PIC-in-PIC box with RCA and BNC ins.

The output of that will go to a 4-WAY splitter and those will go to 4 Composite inputs (which are RCA) on LCD TV's.

The lengths are less than 35 feet each.

Thanks...
Old 17th September 2011
  #2
Lives for gear
 

You should use coax for video, and check your spec.
Old 18th September 2011
  #3
Yeah, video is hard enough to get right with the correct cable. Rg59 is probably your go! Mic cable would be way the wrong impedance!
Old 18th September 2011
  #4
Gear Nut
 

OK, thanks for the input guys... I was thinking that would be better, I was just thinking that so many small cams have small RCA cable and or the composite TV adapters are RCA to 1/8" via small cable.

So I was curious... thanks
Old 18th September 2011
  #5
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Quote:
Originally Posted by clarocque View Post
OK, thanks for the input guys... I was thinking that would be better, I was just thinking that so many small cams have small RCA cable and or the composite TV adapters are RCA to 1/8" via small cable.

So I was curious... thanks
But it is supposed to be the yellow one (the small video RCA) Audio signals are under 20kHertz, video is much higher.
Old 18th September 2011
  #6
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Boschen's Avatar
 

Avoid the temptation to substitute; use the correct cable spec and connectors. For video cams, this means RG59 siamese cable with an 18/2 stranded copper pair for power. Use standard compression (not crimp) connectors, and power pigtails or screw on DC connectors for the power termination.

I've installed probably a hundred miles of RG6 and RG59 over the last ten years, for video and audio. Cheap cams use high gauge cables, and suffer from loss and attenuation over even short distances. They are easy to damage, and cannot be re-terminated. Don't use them.

Mic cable might also be a problem with the power and video running over twined cables--inductance interference, etc. I've done video+power runs over Cat5e with a balun successfully, but I try to avoid this when I can.

Make sure you get the proper compression connectors for RG59--- the crimp style ones are a real pain, have three pieces to assemble, and are just not reliable. You will also need the proper coaxial stripping tool, and a compression tool to terminate them. You can often rent termination kits from local wire suppliers--the tools cost about 30$ for the stripper and 75$ for the compression tool to buy.
Old 18th September 2011
  #7
Gear Nut
 

I went with RG59 (ordered the cable)

Thanks for input...
Old 18th September 2011
  #8
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Boschen's Avatar
 

Bravo on getting the right wire for this project!

As an extra, I like these cams for interior use, and they are a great value at 60$:

CNB DFL-20S Monalisa Indoor Dome 600 TVL

I've installed about a hundred in the past six months, and I've found them an excellent value. 600 TV lines gives a great picture, and it does ultra low light with no IR on a 1/3" sony chip. They also have a 3 axis design, so you can point them anywhere, and come with a power pigtail and mounting template. A good buy.

Have fun with your cams!
Old 18th September 2011
  #9
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Quote:
Originally Posted by Boschen View Post
A

Mic cable might also be a problem with the power and video running over twined cables--

Make sure you get the proper compression connectors ...the crimp style ones are ...just not reliable..
About 1985 CB,I did a test on BNC connection methods and did not find a reliability issue among any properly-constructed ends. And there's the rub... are they well-made?

In terms of what can run with what, we in the audio world tend to try to keep our signals as isolated as possible. But in the broadcast TV world it is a whole different ballgame, with video running in a common cable along with camera power and headset lines and spares, hundreds and hundreds of feet.

There is also media wire designed for installs. I've not used any. There are various configurations and I understand that it is not cheap, but for an install it could be worth the cost. Must be pretty clean to run one cable where several had to go before, and skip all the wire ties, spiral wrap, or whatever.
Old 18th September 2011
  #10
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To clarify, I've found crimp connectors to have several issues, although the problems primarily come from the fellows who connect them, not the hardware. And as Bill points out, therein lies the rub.

A properly terminated crimp will do fine service, and they are a bit cheaper than compression connectors. The reason I don't like crimps comes to ease of installation and installer error. Crimps are just easier to botch, based on their design. I field a crew that does this work, and we need connectors that install quickly, easily, and reliably. It's annoying to have to grub around for that BNC pin you dropped off a ladder, or to assemble a three piece connector in less than ideal conditions. I can strip, prep, and terminate a compression connector in total darkness in about three minutes--I know because I've done it.

The crimps have slightly varying crimp diameters, so you have to have the right die set for your tool, and keep several sets handy. Use of an incorrect die set will over crimp and pinch the cable at the ferrule. At the initial termination, or over time, this causes the cable to work loose from under the ferrule, especially if it gets flexed, as they often do at the video / DVR end of the trunk. I prefer the compression type tools, which don't use a die; at least, mine doesn't.

The crimps also have more ways to mess up the assembly of the ferrule, short the pin and ground, etc. They tend to leave a fringe of shield wire outside the ferrule at the end of the termination, which is annoying. This fringe can corrode and wick moisture into a connector if it's in the elements. I've also found that the shorter body of the crimp connectors seem to result in a connection that is easier to crimp short, resulting in a failure.

Can you tell I hate them? Lol.

Again, this is a problem related to the installer, not the connector. But it's a good reason to use the compression connectors.

On common power and video signals; as I said, I've run wire with common, unshielded pairs carrying power and video signals over UTP. In long runs of this type, like commercial TV AV, the power wires usually have individual shields and drains, so interference is not such an issue.
Old 18th September 2011
  #11
Gear Maniac
 

It depends on what you're going to use the video for. I know a casino survelliance guy who commonly uses CAT5 with a balun (transformer) at each end. CAT5 on the other hand is made to handle high bandwidth and the twists are much more even than audio cable. If you're use is just for a reference to see the person in an iso room and you don't mind a little noise in the picture, audio cable might work.

Buying the RG59 was the correct way to do it (plus you're not running odd HF and possibly glitchy DC right along next to your audio). You did the right thing, it should look great.
Old 18th September 2011
  #12
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Boschen's Avatar
 

Quote:
Originally Posted by Dogoth View Post
It depends on what you're going to use the video for. I know a casino survelliance guy who commonly uses CAT5 with a balun (transformer) at each end. CAT5 on the other hand is made to handle high bandwidth and the twists are much more even than audio cable. If you're use is just for a reference to see the person in an iso room and you don't mind a little noise in the picture, audio cable might work.

Buying the RG59 was the correct way to do it (plus you're not running odd HF and possibly glitchy DC right along next to your audio). You did the right thing, it should look great.
Yeah, cat5e with a balun is often standard for longer video runs where attenuation renders rg59 less useable; these baluns are passive, so no power supply. I also run lots of shielded cat5e for long distance commercial HDMI video distribution over baluns, but these take a powered balun.

You could use a balun with screw terminal connectors to run video + power signals over audio star quad cables or such, but it's likely to create more failure points and issues than a properly terminated siamese coax line. These baluns can also be more fragile--on some, just bumping the balun makes the picture jump about or grey out. They also make good cable organization a bit of a pain.
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