Cable Specifications and Design Problems

[Bob La Londe 0]

I recently have gone through some headaches with a system. It is using Toshiba IK-64WDA cameras with Tamron 2.8-12mm auto iris lenses. They are all tied to a Dedicated Micros DS2.

 

Here is the problem. An electrician ran the cable for the job. Because some of the distances I specified RG-6 95% Cu. I also specified that a 16X2 overall jacketed should be home run for each camera location to a central location where I intended to install an Altronix multi camera power supply.

 

The distance to the furthest camera is about 850 feet. The actual cable length may be 900 feet when you count the various places where it comes up and down to J-boxes etc.

 

Problem 1:

Initially they started to install CATV cable with aluminum shield. I stopped by the site and complained. I very carefully explained that it needs to be RG-6 95% Cu which is designated as a CCTV cabel not a CATV cable. They supposedly replaced with a Belden cable that was marked RG-6 95% TC. The TC supposedly meaning tinned copper. It looks and performs like aluminum, and it has a foil that looks and performs like aluminum.

 

Belden swears the cable the electrician claims they used is adequate for CCTV applications in the distances run. I called Belden and the guy I spoke with swore it was the best cable Belden made. He refferenced broadcast applications many times. The cable is labled for 3ghz applications. That would make it fine for CATV with hyperband and wonderful for DSS satellite applications. That does not mean to me that it would be good for the low frequency signal of composite video.

 

I have been having bad problems with signals from all the furthest cameras, and occassional problem from most of the cameras. The problem is a badly distorted image that the DS2 keeps showing as camera fail. When I hook them directly to the monitor I get a little side to side distortion. Some are worse than others. I get a good picture at the cameras of course.

 

Problem 2:

I have discovered that of my 6 worst cameras the cable for six of them has been spliced in atleast one location. At least four of the cables to these cameras has been spliced in a second location. The electrician used Radio Shack screw on F connectors and F bulkheads. I replaced them at one location with good crimp on connectors. In fact I respliced them twice. Once using BNC connectors and BNC bulkheads and once using good crimp on 0-ring sealed F connectors with F bulkheads. I seemed to get marginal improvement with using crimp on F connectors for the splice. The other splices are in difficult locations to resplice and I did not locate them until nearly the end of the day. Two of the secondary splices had been stuffed up inside of a conduit to hide them, and two other were in a J-box nowhere near a run to a camera. I suppose they never figured anybody would open that box and look. There may be more splices out there. I have not yet opened every box on the premsie and pulled back on all the cables to find out.

 

Problem 3:

Instead of running a pair pair to each camera like I specified the electrician ran 120VAC to each camera. In fact, they ran 110VAC into the camera housings for each camera. I wnet ballistic over the stupidity of this. Their job was done and becasue te facility was basically complete it was no longer practical to run new conduit. There was no possible way to run power wire to the cameras now. Finally they agreed to put up a large J-Box next to each cameras and put a 120VAC outlet inside the J-Box where we could plug in a transformer. WE ran a flex fvrom the J-Boc to the cameras housing and installed a transformer to power the camera and housing.

 

I am convinced that the solutions to this problem is to jerk out the TC cable and all of the splices. Then replace it with RG-6 95% Cu with no splices anywhere. I estimate the price to the customer to do this at about $3800 for cable and $1500 for labor. Since it is not a problem of my causing I refuse to pick up the tab.

 

I have considered using composite video line amps, but because this is an outdoor application the heat may be an issue for their longevity. There are J-Boxes near each camera, but it is out in the sunlight. They still cost a fair amount, and again I am not willing to pick up the tab. Before I offer this as a slightly cheaper option to the customer I want to make sure it would work. The last time I checked a good line amp for composite video was around $300. Multiply that by twelve cameras plus the labor to install and adjust them and its close to the same price as replacing the cable.

 

What other possible solutions do you suggest?

[jimbo 0]

Well it's nice to see a familar name. (I used to watch the alt.security.alarms ng several years ago and pop in every once in a while to see if much has changed - NOT MUCH!)

 

I hope you spec'd the job in writing - if so I wouldn't pay the guy until it was completed properly.

 

Good spec's (written of course) are a wonderful thing for the customer and a *** for the supplier (not only does it keep them honest but they can also put some incredible restrictions on the work)

 

Anyway back to the job at hand. I don't know if the cabling is laid out in such a way that you could run UTP and pick up several cameras on the same run. I have become a big fan of UTP in the last couple of years and used it to replace coax on sites with noise and grounding problems.

In any event I'd replace the cable. Amps and Slope Equalizer boxes are just another item to break down as opposed to cable which when installed properly just chugs along for ever.

[CCTVmofo 0]

i agree. UTP would be the best way to go when traveling more than 500 feet, even better than RG-6.

 

The problem that you are having with the picture on the DVR is due to signal lose. Whenever you splice a cable and reconnect it using connectors you decrease the signal that will eventually get to the DVR. Couple this with an extremly long run and your end result is a flipping image.

 

You were originally correct when it came to the power suppy, the altronix power supply would have defintly been the right way to go. But since that is no longer an option you may want to make sure that the cameras and housings are being run off of heavy duty power supplies, like a 24volt 50va. If they are not then that can cause additional problems, including but not limited to; bad picture, short camera life and a none fuctional housing.

 

DVR's are especailly sensitve to signal loss so even with the slightest drop in line voltage you could end up with a "flipping" image. To that end, if you do end up getting some of the cameras on UTP then you will defintly not want to skimp on your Baluns. I would suggest NTV or Nitek. You can find those items on spytown.com in the video signal products section.

 

I would recommend you purchase the equipment on your own and make the installer do the labor again especially because he dropped the ball.

 

Hope I was able to help.