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I need to make a cable run of approximately 150 feet. The source is a security camera box and the destination is a large ~42" television with all the basic hookups.
The source box is in a room right next to a cat5 ethernet wall jack and so is the destination television.

Is there a way I can use the existing ethernet cabling to transmit the signal from my security camera box to my television 150' away?

The security system box itself has these 'balums' which connect to it by bnc from the camera so could the same 'balum' be used to send the signal out to my television?

What kind of special adapters will I need in order to run it over bnc -> ethernet -> coax?

How much signal degradation should I anticipate?

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  • \$\begingroup\$ Are the two ethernet wall jacks connected to each other with a single point-to-point cabling connection? Or can they be connected that way? Or do they run to a central location where there is a router or switch? \$\endgroup\$
    – user57037
    Commented Feb 17, 2016 at 17:06
  • \$\begingroup\$ They both pass through a switch. \$\endgroup\$
    – gh0st
    Commented Feb 17, 2016 at 17:07
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    \$\begingroup\$ The "passive" solution @uint128_t is proposing will not work if they go through a switch. You could unplug the two cables from the switch and join them together with a "double female" or you could use some kind of converter (instead of a passive solution) to digitize the video data and send it through the switch as data packets. Then you would need to decode the data at the TV. \$\endgroup\$
    – user57037
    Commented Feb 17, 2016 at 17:10
  • \$\begingroup\$ Very good point to mention. Is there not some kind of setting I can make on the switch? It's a nice 24 port Cisco switch. \$\endgroup\$
    – gh0st
    Commented Feb 17, 2016 at 17:12
  • \$\begingroup\$ I have edited my response, given that the cable runs pass through a switch. My original answer neglected this fact. \$\endgroup\$
    – uint128_t
    Commented Feb 17, 2016 at 17:35

2 Answers 2

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Edit: OP has added that the Cat5 runs are connected via an Ethernet switch. Therefore, original answer (left below) is incorrect.

Because the cabling is attached to a switch, you cannot connect analog video to the switch. There are a few options:

  • Ignore the ethernet and separately run your own cable (either coax or Cat5).

  • Depatch the ethernet from the switch and couple the ends together. Then you can use baluns (make very sure that the cable is no longer connected to the switch).

  • Buy a composite video to IP video converter. AFAIK, these are not very cheap. But they allow you to connect the analog camera into the network.

  • Ditch the existing cameras and buy IP cameras that can connect directly to your network. Low-quality IP cameras are very inexpensive, and are very easy to manage once connected to the network.

Once the video is on the network, you would need a small computer to view the stream on the TV.


Original answer

You can buy BNC-RJ45 baluns; they're all over the web. In fact, you can buy a nice little unit that runs four BNC lines into a single RJ45 connector. You should expect a little bit more loss than coax, but it's hard to say how much the image quality will degrade.

If passive baluns don't cut it, there are active converters that use proper differential signalling and have some amplification/pre-emphasis. As it's hard to know which you need, I'd suggest buying passive baluns, see if they work, and if not get some active converters.

I should point out that this solution will only work if you are sure that it is a single continuous Cat5 run. If the Cat5 is run to a switch, this will definitely not work and may cause the switch to be unhappy. If you want to run video over a network, you are better of just buying IP cameras that can run video directly over the network.

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  • \$\begingroup\$ Exactly! This would work perfectly on the source end. But what about on my destination side? Which has the male coax threaded end like conventional televisions? \$\endgroup\$
    – gh0st
    Commented Feb 17, 2016 at 16:37
  • \$\begingroup\$ I think you are confusing video formats. What comes out of your camera is composite video (at least, that's my guess based on your description). Composite video is typically carried over coax and commonly uses either yellow RCA plugs or BNC connectors. The coax F-connector on the back of your TV is meant for an RF input (for OTA, cable, and satellite). You need a composite video input, which is almost always a yellow RCA jack. \$\endgroup\$
    – uint128_t
    Commented Feb 17, 2016 at 16:41
  • \$\begingroup\$ Ah! Ok so I need to find an ethernet to composite converter for my destination end. Do those have a special designation like RJ45-Composite or RJ45-RCA? \$\endgroup\$
    – gh0st
    Commented Feb 17, 2016 at 16:43
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    \$\begingroup\$ To be pedantic: this has nothing to do with Ethernet (Ethernet is a link layer protocol that just happens to commonly run on Cat5/RJ45). You should be able to use the same RJ45/BNC balun on both ends. This will get you back to BNC, from there you can convert to RCA. \$\endgroup\$
    – uint128_t
    Commented Feb 17, 2016 at 16:45
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Your simplest approach is not to worry about Ethernet at all. If your camera has a BNC output, as unit128_t has stated it is almost certainly composite video, either NTSC or PAL, depending on whether you are in the US or Europe. This is an analog (or analogue) signal, and if you want to use Ethernet to communicate with the display you'll need a video A/D converter as part of a computer at the camera to convert the analog signal to digital packets. Then, of course, you'll need another computer at the display to accept the packets and either reconstruct the video waveform or format it into something like HDMI. I doubt you want to do this.

So, what you should do is to get a length of 75 ohm cable, and install a BNC connector on one end, and an "F" video connector or RCA plug on the other, depending on what your TV takes. Connect the BNC to the camera and the F/RCA to the other. If you're looking for easily-found parts, BNC on both ends and a BNC to RCA or BNC to F adaptor on the other will work fine.

Standard 75-ohm coax is RG59, and for camera outputs (signals are less than 10 MHz) 150 feet should give quite adequate transmission quality, If you want to get the best, go with RG6 instead, although it's harder to get and is more expensive.

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  • \$\begingroup\$ I agree the simplest approach is not to worry about ethernet. But the ethernet foundation is already there and I'd really like to take advantage of it. Instead of running new coax line I could jack right into the existing ethernet ports. \$\endgroup\$
    – gh0st
    Commented Feb 17, 2016 at 17:18

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