CCTV + pOE problems

[Joe Shmoe]

Any Cat5e/POE experts here?

I'm having issues with a new CCTV camera.

It's powered via POE from the NVR. Basically it all works fine when using a short 5m cat5e cable. As soon as I use the 50m cable that Ive wired myself, it doesn't work. The camera turns on and the IR LEDs illuminate, but the NVR just won't detect it. (it does when using the short cable).

I've used good quality cable and RJ45 connectors. I've checked that I've wired it the same both ends using a cheap Cat5e checker that you connect both ends and the 8 little LEDs light up in sequence.

I've even used a POE injector incase the NVR wasn't up to the job, but that didn't help either.

It's obviously something to do with my cable, but I can't see what as the tester says I've wired each end the same. Any tips?

 

[Steliz]

I would agree that it seems the problem is with your 50m cable. I have a camera on a 50m cable and I don't have any problem with it although mine was pre-terminated when I bought it. The cable should be UTP (untwisted pair) which means the same connections at each end.
I use a swann NVR and cameras.

 

[RichardG]

Some ramblings which may help....

Logically there are 2 things to confirm, first is the PoE supplying enough power, second are the Ethernet signals at sufficient level. The fact that the camera shows lights indicates that the PoE is working but it may not be completing its power up cycle if the power is lacking. Does your camera support local powering, if it does try using a local PSU and confirm than the camera signal works over the 50m cable. If not when the camera is working on the 5m cable can you disable the IR LEDS (they draw a lot of power), then try the 50m cable, again may help.

Does the camera specify a max PoE distance, I use Hikvision cameras which state 100m but they do also have local power for longer distance. Highly recommended by the way.

Is the camera using DHCP, if so has it requested an IP address?

Can you sniff packets to see what’s going on?

What model camera/nvr is it, I have a look to see if there’s anything else I can suggest.

Richard

 

[Racers]

+1 for the local psu it could be voltage drop across the cable, or too long a distance for the video signal.

UTP is unscreened twisted pair, it needs to be twisted to screen the signals.

Pete

 

[sunnybob]

I had a 75 foot cat 5 extension cable on my wi fi router last year, it needed another power supply to work properly. It was so much hassle I rewired to do away with the run.
If you cant make the line shorter, i think another PSu will do the trick

 

[Sheffield Tony]

Bit surprised if the cable length is a problem. The spec from a data transmission point of view is <=100m. PoE can come in different flavours; is the connection to the camera 100Mb or 1Gb. If the former, only 2 pairs are used for data and (most commonly) the two spare pairs for power. If the latter, all 4 pairs are used for data and power. Cat5e is usually 24 AWG, which is ~0.07 ohm/metre, so even if only over 2 pairs you have 3.5 ohm (2 cores, 100m there and back), and at a heavy load of 1A (48v PoE, 48W towards the upper end of what is available) you should have an adequate >44v at the camera.

Sure you have the right cable, with well fitted connectors, of the right sort for the cable (solid / stranded) ? Also some poor quality crimpers can damage the plastic body of the RJ45 connector so not all circuits are made reliably.

Cheap power injectors normally just supply power via two unused pairs and don't work at 1Gb.

You may be better using screened / shielded cable and RJ45 connectors for PoE applications; switching power supply noise can radiate nicely with unshielded cables.

Finally, why make your own cables ? is it so it passes through a small hole ?

 

[Eric The Viking]

Richard G and Pete M have both made some good points.

Despite passing on the cable tester, I'd double check the correct pairs are twisted together in the cable (cable testers don't test this, and it's very important), by removing the outer sleeving from an off-cut.

I'd also check if it's solid or stranded wire. The latter is really only for wall-to-desk connections, for example in the office, and doesn't work well with the IDC connectors used for CAT5. I have professional tooling for both patch leads and wall plates, but stranded CAT5 (as opposed to the solid-core stuff) has caused no end of poor connections here because some fool (me) bought a cheap 500m box for the house before he realised it wasn't suitable for Krone block connectors. It's OK-ish for patch leads, but you have to make them really carefully, and make sure the cores go right to the ends of their little guides in the plugs, before you squeeze the tool. If in any doubt, it's worth re-making the ends (snip the plugs off and use fresh) just in case.

The issue related to having the right pairs twisted together is external interference. Twisted-pair on its own is far from bomb-proof. CAT6 has an extra overall screen, which really helps, and that's why it's specified for longer runs. You may get a handshake with a hub/switch showing it's a gigabit link, but if there is interference, operational data rates can be a lot lower.

Is there any way you can borrow an equivalent length (or slightly longer) of CAT 6, and try it instead of what you've put in? If it does work, there's probably a source of interference somewhere that's causing the CAT 5 to not work.

Interference would be my first guess, followed by PoE not being able to deliver the necessary current over that distance via the cable you are using. If your camera works correctly with the PoE injector right on the back of the camera unit (i.e. with a short patch cord, and the link to the NVR still going down your long run), that's most probably it.

By the way, these cameras often have an earth point (a screw) on the case somewhere. If you use it you will most probably make matters worse over that sort of cable run, so don't, unless the instructions give you a reason why.

HTH, E.

 

[Dibs-h]

Joe,

What kind of cable are you using? Solid copper or the cheaper aluminium one? I've got something like a 30 odd metre run between an NVR and an IP camera and it runs fine - admittedly it's solid copper, not stranded. I've used the same cable and connectors to flood wire a building for wall sockets and a patch panel with lengths approaching 50m and not had any issues there either.

Also have you wired it A or B?

Have you tried the cable in a laptop\desktop?

Daft as it may sound - I'd be tempted to make a something like a 1m cable with your cable and connectors and test that things work.

If the cable isn't fixed in position - perhaps use a multimeter on continuity setting to double check that the cable is fine and there are no intermittent "breaks" in the cable.

HIH

Dibs

 

[Robbo3]

I also doubt it's the cable length that's causing the problem. Although mine are on 15m runs & ready made leads I know of several people who run POE IP cameras on runs at least as long as yours.
I've found that my eyesight & finger strength are not what they were & terminating some Cat6 cable (because I was given it) I failed to make a sufficiently good connection twice. I then purchased some open ended/pass through RJ45s which allows you to see that the wires are correctly located. That solved my problem.

 

[Sheffield Tony]

Heaven knows why RJ45s aren't all made that way, it removes all the fiddling getting the wires exactly the right length, and the uncertainty. Equally, why is it so hard to find a reasonable hand tool - so much cheap rubbish with mild steel dies.

 

[Dibs-h]

Heaven knows why RJ45s aren't all made that way, it removes all the fiddling getting the wires exactly the right length, and the uncertainty. Equally, why is it so hard to find a reasonable hand tool - so much cheap rubbish with mild steel dies.

TBH Tony, I've got a couple (only because one got put in a super safe place & I couldn't find it when I needed, so bought another one, then #1 turned up) and they don't strike me as remotely expensive - done 100's of crimps with both and never had any issues. What kinds have you had?

Joe - any update with your cable\camera problems?

Dibs

 

[Sheffield Tony]

With the cheap crimpers where the dies are not hardened, the pins that press the contacts home gradually splay, then start scraping a slither of plastic from the sides of the shell. Being clear plastic, very hard to see even with a magnifier, but stops usually the outer 2 circuits making reliable connection. It being usually the outer 2, the resulting cables work fine at 100Mb, but not 1Gb. Correction by taking a file to the die did work at least temporarily.

Forgot to say - generic no-name, maybe CK. Cheap ones.

 

[Dibs-h]

With the cheap crimpers where the dies are not hardened, the pins that press the contacts home gradually splay, then start scraping a slither of plastic from the sides of the shell. Being clear plastic, very hard to see even with a magnifier, but stops usually the outer 2 circuits making reliable connection. It being usually the outer 2, the resulting cables work fine at 100Mb, but not 1Gb. Correction by taking a file to the die did work at least temporarily.

Forgot to say - generic no-name, maybe CK. Cheap ones.

Cheers for pointing that out - something to keep an eye out for.

I've just looked at one of my el-cheapo ones and the outer 2 pins are perfect. Maybe get "better" quality plugs or maybe less brute force? LOL