Loose BNC connection problem

[todd2 0]

Have DVR with several BNC terminals on the back. Bought several 25' BNC to BNC siamese

cables to connect cameras. I've found that I get occasional problems from loose connections

between the connectors on the back and the cables. Occasional meaning that in practice

it only happens once in a while but I can reproduce the issue by touching the cable end.

(Yes the connectors are locked, give me some credit.)

 

I don't believe its a loose connection inside the DVR since the BNC terminals themselves

are not loose and the problem seems to happen equally between all the terminals (not just one or two).

 

So, naturally, I assume the cable, right? However, testing the cable at home, it seems

OK with the connectors I try. So all I can make of the issue is that the diameters or

natural manufacturing tolerances between the cable and terminals must be off enough

to cause the issue. I do find that if I connect an RCA cable with a RCA to BNC adapter

(about 1 inch long) that connection doesn't have the problem, again seemingly implicating

a terminal/connector sizing issue. Comparing the back of the RCA adapter and cable does

show the gap is different between the shield and center piece of the BNC connector.

 

So, just try some new cables? Cheapest cables that don't look like the same (probably

Chinese) manufacturer are like $15 a piece (for 25' cable), so if it's something else

I guess I'm tossing that money away.

 

Anyone face this issue before? Is there a good name brand 25' siamese cable? (I'd prefer

not longer since for my application the cable would have to be tucked away and longer

cable just has more potential for voltage drop and other issues.)

[bpzle 0]

25' Siamese cable? Sounds like cheap pre-made stuff. You get what you pay for. I only buy RG59 Siamese in bulk (500' or 1000') and make my own ends (compression BNC). I say only... but it's been a while since I've used RG59 at all... Ran out of my last roll about 6 months ago and been using UTP ever since...

[rory 0]

Well you have a couple choices:

 

1-Splice the existing cable and add a short piece of RG59.

 

2-Change the cable for Rg59 Siamese one time, just visit your local electrical store and they should carry it, ask them for video cable, Siamese, they even sell it down here now, and its not that expensive (40 cents a foot but we are 3-4 times the US cost).

 

In both cases make certain the cable is copper in and out and solid center, should be with the siamese but who knows what RG59 they have lying around.

 

then add a twist on BNC connector done properly, you might find them at the same electrical store or even a local computer store.

 

Bottom line is that all in one cable is a problem, cheaper in some cases but can cost more in the long run. If you have a local source for really good Cat5 Baluns then you could also look at going that route now, if you might want to upgrade to IP/Megapixel cameras at some point in the future. OR, if you can afford it, and if you are going to rerun Rg59 Siamese cable now, then perhaps pull some cat5 along with it one time. If the runs are short and easy though then dont even worry about it, just pull the RG59 Siamese, you could always use that to pull new wire later.

 

Oh yeah, I ONLY use Rg59 Siamese cable right now ... but eventually cat5 might be the way to go. Either way, even for budget jobs, I use RG59 Siamese instead of the all in one budget cables, its just cheaper and twist on BNCs are more accessible here. If you do the twist on BNC right, that will last for years.

[todd2 0]

Actually, I don't want the RG59 style because the cables are thicker. I need to run it

through the interior panels of a vehicle, so I need the thinner cable. I'm ok with a little

degradation, but that's not what I'm seeing. I'm seeing an issue at the cable end

(when I jiggle it around).

[rory 0]

Ok sorry my bad.

Could try to simply tape them to make sure they are not grounding out (touching each other)

Or splice them so there is no connector at all, ground to ground, center to center.

they are most likely going to both be RCA type braid cable so look for some crimp type connectors that alarm companies use, called beenies. Or goto Radio Shack and pick up some heat shrink tubing and use that instead.

[bpzle 0]

Should have mentioned it was going in a car to start with...

There's going to be a lot more issues at play in a car... how are you powering the DVR and cameras? Is the DVR designed for automotive use? Does this signal problem happen with or without the car running, or both?

 

Cheap cable ran next to other wires in a car will definetly pick up noise.

 

It's also possible that the noise isn't coming from the cable at all but the power source. DC/ AC inverters tend to create pretty dirty signals... It may just be that jiggling the cables isn't related to the real problem... Kinda like touching a radio antenna when it's tuned into a weak signal. You'll notice that you seem to be interfering with the signal...

[Tailbone215 0]

If you are doing mobile installations, especially ones you don't want to revisit because of quality issues, you might want to consider using RG-179 cable as it is extremely thin. You can get the good stuff, silver plated copper shielding and center conductor which reduces loss considerable. This stuff is MIL spec and is extremely durable. You can also get this stuff in RG-59 as well. I wouldn't use the cheap stuff in mobile installations and I would avoid twist-on BNC connectors at all costs in this environment. Here's a link to some RG-179 cables with BNC on both ends.

 

http://www.stonewallcable.com/product.asp?dept_id=3013&pf_id=SC-7232

[bpzle 0]

I would avoid twist-on BNC connectors at all costs in this environment. [/url]

 

+1

[survtech 0]

+ 2 - and I would avoid them for any installations. They do tend to come loose!

[Guest]

If you are doing mobile installations, especially ones you don't want to revisit because of quality issues, you might want to consider using RG-179 cable as it is extremely thin. You can get the good stuff, silver plated copper shielding and center conductor which reduces loss considerable. This stuff is MIL spec and is extremely durable. You can also get this stuff in RG-59 as well. I wouldn't use the cheap stuff in mobile installations and I would avoid twist-on BNC connectors at all costs in this environment. Here's a link to some RG-179 cables with BNC on both ends.

 

http://www.stonewallcable.com/product.asp?dept_id=3013&pf_id=SC-7232

 

I agree.

 

We use RG179 for all our rack and vehicle work.

 

Also to manage the transition from large coax to the kit as you damge kit by connecting heavy cables like CT125 or RG11.

 

Limit the run to less than 10m though as it is very lossy.

 

RG179 cable is also available as a 5 core from the broadcast TV industry.

 

It does not pay to try to save money on cable or connectors.

 

Indentify suppliers who supply good quality cable and connectors and stick to them!.

 

You will always be able to buy cheaper, but it will come back to bite you eventually.

 

I am sure the old hands on this forum will back me up on this.

 

Ilkie

[rory 0]

+ 2 - and I would avoid them for any installations. They do tend to come loose!

That is incorrect.

If one uses RG59 connectors on RG59 cable, and puts it on properly, one can literally hang from it, and it will never come off. But we have gone over this topic before.

[Tailbone215 0]

+ 2 - and I would avoid them for any installations. They do tend to come loose!

 

I must admit I kinda like them as I get to clean up the previous installer's mess and make some quick pocket change. In fairness twist-ons can be good if properly installed. The issue is finding a tech that actually knows how to correctly install them is the real challenge.

[rory 0]

I must admit I kinda like them as I get to clean up the previous installer's mess and make some quick pocket change. In fairness twist-ons can be good if properly installed. The issue is finding a tech that actually knows how to correctly install them is the real challenge.

 

That is correct, however the same could be said about Crimp Ons. It really is up to how good the installer is, regardless of which connector is used.

[Tailbone215 0]

If one uses RG59 connectors on RG59 cable, and puts it on properly, one can literally hang from it, and it will never come off. But we have gone over this topic before.

 

True, but I think one must distinguish between a quality install vs a quick and convenient get your butt out of there install. They have the same idea in the electrical trade, at least in the US. One can properly wire receptacles a switches by using the screws. The quick and dirty way is to use the push-in wiring holes. While it is NEC accepted they make a great fail point, especially when under load since they can't carry the current because of lack of surface area between wire and device. I've seen to many of them fail, especially when receptacles are wired in series. I would rather waste a few more seconds doing the right instead of wasting time and embarrassment of a callback.

[rory 0]

True, but I think one must distinguish between a quality install vs a quick and convenient get your butt out of there install. They have the same idea in the electrical trade, at least in the US. One can properly wire receptacles a switches by using the screws. The quick and dirty way is to use the push-in wiring holes. While it is NEC accepted they make a great fail point, especially when under load since they can't carry the current because of lack of surface area between wire and device. I've seen to many of them fail, especially when receptacles are wired in series. I would rather waste a few more seconds doing the right instead of wasting time and embarrassment of a callback.

 

There is no reason why a twist on would fail more then a crimp on once both are done correctly. If that is what you are suggesting? Anyone that says a quality install can not be done using twist on BNCs is simply wrong, but they are certainly entitled to their opinion.

[bpzle 0]

I'd have to disagree Rory. Compression is all I use. I've not once had to go back to fix a compression fitting. But I've seen way too many fail points over the years with twist and crimp ons. As a matter of fact, if I ever see twist ons in the field I just go ahead and cut them off regardless if they're working or not. I just don't want to get blamed for something I know will fail eventually, maybe even 5 minutes after I leave.

 

They just fail over time from wiggling. It would only be worse in a car...

 

Imagine having a CATV guy come to your house and breaking out some RG6 twist ons! hahaha I'd kick him out.

 

Twist ons only have one purpose IMO... They're for DIY'ers that need or want to save money and don't need to invest in the tools for a one time use.

 

Think about it... its a device that's attached and secured using nothing but hand strength. I don't hand tighten anything. Why would I for critical security connections?

[Tailbone215 0]

There is no reason why a twist on would fail more then a crimp on once both are done correctly. If that is what you are suggesting? Anyone that says a quality install can not be done using twist on BNCs is simply wrong, but they are certainly entitled to their opinion.

 

Don't get me wrong, I do agree that a properly installed twist-on is reliable and secure when the tech knows how to do it. I have no problems installing them because I know it will be done right. I don't use them because it might give the appearance of a hack job. Throughout the years I've seen and corrected more twist-on disasters than crimp or compression. If I'm going to charge to correct someone else's slop I'm not going to reuse their connectors. It looks tacky and takes more time explaining to the customer. Snip, trash, and replace is the logical way to go. The bottom line is if an installer can't get something as basic and elemental as terminating a cable end right the first time it looks bad for the industry as a whole.

[rory 0]

I'd have to disagree Rory. Compression is all I use. I've not once had to go back to fix a compression fitting. But I've seen way too many fail points over the years with twist and crimp ons. As a matter of fact, if I ever see twist ons in the field I just go ahead and cut them off regardless if they're working or not. I just don't want to get blamed for something I know will fail eventually, maybe even 5 minutes after I leave.

 

They just fail over time from wiggling. It would only be worse in a car...

 

Imagine having a CATV guy come to your house and breaking out some RG6 twist ons! hahaha I'd kick him out.

 

Twist ons only have one purpose IMO... They're for DIY'ers that need or want to save money and don't need to invest in the tools for a one time use.

 

Think about it... its a device that's attached and secured using nothing but hand strength. I don't hand tighten anything. Why would I for critical security connections?

 

We will have to agree to disagree then. I have never EVER had to fix any of my connections, ever. One cannot compare Cat TV twist ons to BNC twist ons, they are completely different.

 

Twist on BNCs are used by CCTV professionals, anyone that says otherwise is simply out to tarnish the reputation of other installers and it is not a good idea. Also, while you are cutting off connectors (and shortening the cable) why not change the cameras to some Professional Box cameras, get rid of those little toy domes and bullet cameras that so many DIYs use. Also, pull out all that flimsy cat5 cable and baluns and put in some solid siamese cable. And place the DVR in an air cooled lockbox, fire proof. Dont connect that DVR to the network either or it can get hacked.

[rory 0]

I don't use them because it might give the appearance of a hack job.

It will only give that appearance to someone that knows nothing about CCTV.

So I would not worry about them.

[bpzle 0]

Maybe I just don't have the crazy hand strength you do Rory. Your hands must be ripped from all those.... uhhh.... posts... 15 thousand something and counting? lol

[Tailbone215 0]

It will only give that appearance to someone that knows nothing about CCTV. So I would not worry about them.

 

One other area to ponder. What if you the installer leave the job site knowing you did all your twist-on connectors perfectly and get a call from the customer that some have failed? You scratch your head and ask yourself how can that be? You get there and see braid hanging out the sides of a few. Who tampered with them? The customer or another contractor? Who do you blame? Is it worth asking the customer? Since compression connectors are one-time deals you remove all doubt. From a price point and labor factor I see no reason to use twist-ons. Deliver quality and finality to your customers.

[Tailbone215 0]

Twist on BNCs are used by CCTV professionals, anyone that says otherwise is simply out to tarnish the reputation of other installers and it is not a good idea. Also, while you are cutting off connectors (and shortening the cable) why not change the cameras to some Professional Box cameras, get rid of those little toy domes and bullet cameras that so many DIYs use. Also, pull out all that flimsy cat5 cable and baluns and put in some solid siamese cable. And place the DVR in an air cooled lockbox, fire proof. Dont connect that DVR to the network either or it can get hacked.

 

Serious question. Why would you want to use twist-on connectors over the newer compression connectors? Both are quick and take little labor to install. Only reason I see is the installer not having the proper tools to get the job done.

[rory 0]

One other area to ponder. What if you the installer leave the job site knowing you did all your twist-on connectors perfectly and get a call from the customer that some have failed? You scratch your head and ask yourself how can that be? You get there and see braid hanging out the sides of a few. Who tampered with them? The customer or another contractor? Who do you blame? Is it worth asking the customer? Since compression connectors are one-time deals you remove all doubt. From a price point and labor factor I see no reason to use twist-ons. Deliver quality and finality to your customers.

 

If they can remove my twist ons, then they are good. I dont even bother, I end up cutting the cable. But If it were to happen they get charged for a service call, just as if they messed with anything else. Additionally BNC compression connectors are hardly available in this country, Twist On BNC Connectors can be bought from pretty much anywhere these days. As mentioned, I have NEVER had to go back to any of my connections, EVER. I mean if they are messing with things, they could just as easy pull the plug on the DVR or Mess up the camera.

 

Arguing over this is the same as saying never put the DVR on the network, it makes no sense. The customer IS getting quality with Twist On BNCs no matter what anyone says, but still, we should look beyond that, are these installers that are using Compression connectors, also using Professional Box cameras, or are they using Toy Domes and Bullets?? One could ponder this in all different directions.

[rory 0]

Serious question. Why would you want to use twist-on connectors over the newer compression connectors? Both are quick and take little labor to install. Only reason I see is the installer not having the proper tools to get the job done.

 

Does the installer have the Camera Master?

Are they incorrectly focusing using an LCD?

Does the installer drive a truck or a van?

Did the installer quote the job in the day and at night?

Did the installer use a viewfinder?

 

These are all silly questions really, except for quoting the job in the day and night, depending on the camera placement. And ofcourse is using an LCD to focus cameras then it is not being done right at all.

 

But you seem to be suggesting that by not having a tool to do compression connectors, which are not necessary hardware for CCTV, that they dont have the tools to do the CCTV job, and if so that is totally incorrect.

 

Forget connectors for a second, just tie the cables together and then this entire debate means nothing, cause that is better then any connector can ever be!

[Soundy 1]

One job, I had nothing but twist-ons to use. After less than a dozen of them, my wrist was sore, my fingertips were getting raw from the knurled barrels, and fingers on both hands were cramping.

 

Why anyone would WILLINGLY choose twist-ons is just beyond me. I guess they prefer manual screwdrivers over screwguns for driving 3" deck screws into hardwood, too... 20' extension ladder over a lift... parking a half-block away from site so they can carry everything farther...

 

You're just too hardcore for us, Rory.