new 24vac camera over old 3 in one cable problems

[WDRJack 0]

I'm in the process of replacing 8 working no-name 12vdc cmos domes with Tatungs (TFD-CVSH26AI24) 24vac domes (that he already purchased) in a previously installed system for a friend of mine as a favor. When I installed the new camera (with new 24vac transformer) using his original wiring (cheap 3 in one- yellow rca-white rca- red 2.1 pig), I get two large distorted lines in the video. I have no problems if I power the camera locally or plug the camera into my portable Ganz monitor. It's seems at 24vac, the cable is good for either video or power but not together. If only 12vdc works, can I use another camera (Ganz ZC-D3210NHA) running at 12vdc? Is there any way of using these existing cables in his drop ceilings (only 1ft of clearance) without running new cables running 24vac cameras? How about try using baluns on both ends? Any help would be appreciated.

[SureVeillance 0]

As you probably know, AC alternates at 50 or 60 cycles and can bleed over to the video signal. That is why Siamese has the video in an rg59 isolated from power on 18/2. So I guess options are

 

1. Check whether the TFD-CVSH26AI24 is 12 volt switchable and use 12 volt DC. Some models are switchable.

 

2. Buy a different 12 volt camera such as the GANZ you mentioned

 

3. Power the cameras locally.

 

4. Run a separate 18/2 wire to each of the cameras to carry 24 VAC

 

5. Buy Siamese cable and tie it to the existing cable and pull it through the ceiling to replace it.

 

Good luck!

[VST_Man 1]

try grounding all three grounds together?

[WDRJack 0]

Thanks for the great ideas guys.

 

Since I'm doing this for free (spend as little time as possible) and my friend doesn't want to spend much money, I'm going to try in this order:

 

1. Use inner wire of the white rca wire with the inner wire of the yellow rca wire to make the 24vac power wire. These wires are like miniature versions of rg59 wires where there is braided wire covering an inner wire. Hopefully the AC alternates won't bleed over to the video signal since there is more insulation between the two.

 

2. Use good quality baluns (Videobaluns Unlimited BL3365) that I have sitting around using same wires as above.

 

3. Run new Siamese cable and tie it to the existing cable and pull it through as a last option.

 

Short of cutting the 3 in 1 wire open in the center where all three wires merge to look at, is it possible these wires share a ground (perhaps the white and yellow wire)?

 

They look similar to these except thinner

 

http://www2.cop-usa.com/ebproductdetail.asp?id=291

[SureVeillance 0]

In my experience, it is not likely that the 3 cables share a ground. The 3 wires likely continue for the whole length very similar to the way they stick out the end, just inside the over-jacket.

[rory 0]

If it is thinner than the cable in the image posted, I would change the cable.

 

That cable in the link are 3 separate pairs, or 6 conductor, where Red is power, yellow is video, and white is audio. Perhaps try doubling up the cables, the distance of the run and the power draw from your camera may also be an issue using wire that thin. Though what SureVeillance said pretty much covers it all.

[WDRJack 0]

I didn't have time to continue on the install today but was so curious what you guys said about the wire that I decided to swing by and clip the 3 in one 1 wire in the center where they bunch up.

 

To my surprise, there were only 4 wires (24 AWG each)- a red, a black, a yellow and a white running the whole length. WTF? Now it makes sense because last time I tried to double up on the wires (using whites both wire as one for a + and using yellows both wire for a -), the transformer green light would not even light up.

 

I won't get a chance again till next Monday but I now know the baluns should work since I have 4 wires to work from.

[WDRJack 0]

Finally got a good picture using the inner wire of the white rca wire with the inner wire of the power wire to make the 24vac power wire.

Hopefully, it will stay that way.

 

Thanks for all the help!