Intermittent transmission problems

[chewingyu 0]

I am plagued by intermittent unserviceability of some of my cameras. According to my CCTV contractor, this is due to the many joints in the cabling works. Apparently, due to the long distances due to the layout of the buildings - stretches about 800m (that's only from plan view and not counting the cable routing up,down, left and right in the buildings) - the RG cables had to be connected with joints.

 

The system was installed some 5 to 6 years ago. So, my contractor says that the wear and tear of the system is beginning to show and signal losses are becoming more significant.

 

I am not sure how true this is but it is really bugging me. It would be too costly to recable the entire network with Cat 5 cables, which I am told has better ranges.

 

In the meantime, how my contractor solves the intermittent problems is to put the soldering gun to the joints that are near the CCTV room where all the recording is done. He says, it is to "heat up" the joints. Now, this solution is only temporal. The problem will come back again after a couple of weeks and if lucky, a couple of months. Now, I do not know how scientific this method is but it sure seems odd. "Heating the joints"??!!

 

I wonder anyone has experienced the same or can anyone tell me that I am being taken in by my contractor??

[DataAve 0]

He is taking you for a ride. Get a second opinion. Where are you located?

Edited August 29, 2005 by Guest

[rory 0]

Never heard of that, but ofcourse a "joint" is going to lower the distance, so joining it together instead of using a connector will help.

 

How many cameras are causing problems?

 

Is this RG59?

 

How much feet is the distance?

 

Possibly look at an amplifier as well. But wire needs to be soughted out first.

Where are the splices located?

 

Rory

[DataAve 0]

Singapore, dang that is a hell of a service call.

[chewingyu 0]

Yes, it is RG59, joined to RG11 (that's what they say)

 

So, there is no such thing as "wear and tear of joints"? Joints are different from connectors?

 

I have, according to this contractor of mine, 7 cameras with this "cabling problem". About a year ago, I had the same kind of problem with 6 other cameras, and did a recabling work but I kicked up such a fuss about it being a design fault that I got them to waive the labour charged and paid half of the material costs! Obviously, they did it at a loss but they ain't gonna do it this time. They blamed it on our decision during installation where they had offered to run fibre optics due distances but we opted for the cheaper solution using RG cables. I told them that that was bull****. If we had opted for the RG solution, then they had better make it darn sure that it lasted. But they claim now that it has been almost 6 years. So there is "wear and tear" of the system.

 

Actually, though they verbally tell me they are reheatin the joints, their service reports says they are "resoldering the joints"

 

Somehow I don't buy all of this but I am somewhat stuck because they won't budge and I need to get the system rectified.

[DataAve 0]

Tell them to use BNC connectors (the crimp type). You can get a RG59 to RG11 connector. Soldering (cctv cables) went out with the horse and buggy.

[rory 0]

Tell them to use BNC connectors (the crimp type). You can get a RG59 to RG11 connector. Soldering (cctv cables) went out with the horse and buggy.

 

Yeah I just usually "tape" them

 

I dont know, what is 300m in feet .. and RG11 ...?

[DataAve 0]

Also, you shoud have run Fiber, because now it will cost you-but that is niether here nor there. There should be no need to go from rg11 to rg59. I never heard of such a thing-unless he had wire he wanted to off. Sounds as if you are in need an honest company.

[chewingyu 0]

There isn't really a need to do recabling is there?

What about improving the joints, like installing connectors instead?

Or installing some signal boosters at those joints?

[qman 0]

Honestly, I would just rewire the whole thing with either CAT5 using active balums, or run new RG wire, straight, with no joints.

 

At this point, no matter what you do, the problem is that the joints, if using BNC twistons, which I suspect, will rust out the brading over time, and you will have the same problem again. Fiber is a costly solution, but I really don't see where you have much of a choice.

 

The best thing to do is to just call someone else to do the job if you are unsatisfied with the work that they have done.

[chewingyu 0]

MAN!

[Cooperman 0]

Oh dear chewingyu, problems indeed.

 

First off, cast your mind back to when the system was originally installed - did it work o.k. then, or has there always been problems with the cabling?

 

From what you've described so far, and obviously without the benefit of more detailed information, it would as Data suggested, have been far better if you had gone the slightly more expensive 'fibre' route from the outset.

 

If the cable joints had been done correctly, it is unlikely to have been any less "lossy" than if in-line connectors had been used instead. The obvious problem is that the RG cables are not really suitable for such lengthy unamplified runs, particularly where each cable joint may be the equivalent of an extra 50 - 75 feet of cable, in terms of signal loss.

 

"Sweating" joints is a fairly standard technique for establishing whether a joint is "dry" and therefore not making a proper contact, but the bottom line is, if it had been done properly in the first place, you may get the odd connection failure over a period of many years, but not to the extent you are reporting. Incidentally, using an engineers freezer spray is also a solid technique for cooling (and identifying) dry joints.

 

It is possible that if the cables have sustained minor damage over the years, damp may have got into the cables and either caused the copper to oxidise, or introduced an effective barrier to proper signal propogation, but the fact that the contractor is resoldering the joints with varying effects suggests this may not be the problem.

 

If you can spare the down time and cost to have individual cables isolated and tested particularly at joint locations (both for cable resistance and also signal display), you may be able to look at existing cables or groups of cables, being (re-) routed to a common point where single channel amplifiers can then be used to beef up the signal transmission.

 

In practice, you need to pick a single cable, have it properly tested, and then try a quality amplifier to see if the technique is appropriate for the remaining problem cables.

 

Failing, that, as has already been suggested you're looking at a limited number of expensive but unavoidable options.

 

Incidentally rory, 300 metres is a bit under 1000 feet.

[rory 0]

So each run is around 2000-3000'? Or thats the total run?

If so I kind of see why they used RG11, but being it was how many years ago, they probably should have used fiber, if it was now they could have got away with Twisted Pair and Active Hubs (NOT Baluns). But if its direct bury you could still end up near the Fiber cost!

[DataAve 0]

"Sweating" joints is for plumbers. This ain't pipe.

[chewingyu 0]

Thanks guys. Will have to deliberate on this for a little while.....

[DataAve 0]

If the cash is not available and your butt is on the line, have them put in BNC connectors. Let us know how you make out.

[chewingyu 0]

My butt is on the line alright! Butt, neck, head...all of it!

[chewingyu 0]

Hi guys, I am back. The problem still persists...intermittent failures and contractor is again asking me to recable!

And guess what, they ARE using BNC connectors.

 

So, my dilemma continues......Do I recable or what?

[rory 0]

get rid of the connectors, splice the cable together and tape it up good.

 

Twist center to center and braid to braid, keep the braid away from the center, do the braid first and tape it up good, tape it around the cable .. then do the center, and tape it, then tape the whole splice up. It will look like a kind of "V" when done, do them inside a electric gang box so they cant be seen or touched, and caulk the holes where they go into the box. I never had a problem doing it this way before, and even using RG59 Copper to RG6 Aluminum, and as much as 3 and 4 joints at long distances.

 

If you want to you could also solder them. Either way it beats running new cable, and it works. Any other issues then there is another problem.

 

Rory

[CollinR 0]

If you want to you could also solder them. Either way it beats running new cable, and it works. Any other issues then there is another problem.

 

Rory

 

This organization takes the lowest bidder.

 

http://www.cctvforum.com/viewtopic.php?t=3941

 

You can bet alot of corner cutting is going on, $6 worth of savings $600 worth of PITA.

[rory 0]

yeah, thats how the government is here with bids, which is why i would never deal with them. Plus someone gotta get paid off and i dont work like that.

[JMANOFNVS 0]

Sorry to be blunt and to quote somebodies closer on here but "you get what you pay for" after 5 years running the cables they used and the technology back then not too mention cost of equipment you are lucky you have a picture at all. With that distance fiber should have been your only option in the bid you put up. Trying to bandage it will only prolong your issue. The price difference in equipment now should persuade your company to fork over the bucks to at least run twisted pair, you can get it in 5000' spools and use some NVT magic and smart design and not cost to much.

[chewingyu 0]

Got to raise this topic again as I am still experiencing this problem of intermittent failures. Again, I have been told that recabling is the only way to solving it.

 

I just discovered that my CCTV vendor is using a remote cable tester to establish if the cable is faulty. Does this device really work and is it 100% accurate?

 

My struggle is that recabling is a such a costly option and I have to be dead-sure that it is THE only option.

[chewingyu 0]

Is the following troubleshooting process enough to conclude that the problem is cabling and the solution therefore is to recable (from camera to DVR)??

 

01. At camera end - replaced with a new camera and checked with the control room - no image.

02. At camera end - plug in existing camera into portable monitor - good image

03. At control room end - inter-switched suspected problem cable to other camera input at DVR - no image

04. At control room end - inter-swtiched working cable into suspected problem input - no image