Shipboard interference in engine room.

[Jburn 0]

Hi, guys, I'm Jay. New to the Fo. My company installs marine electronics onboard large offshore vessels. Recently, they have been asking for more and more cameras installed down in the engine room. The problem with this is the amount of electromagnetic interference in the engine room, and interference in general.

 

The cameras I am using are HD-TVI 1080p cameras. Instead of pulling siamese RG59U, we have been pulling shielded Cat5E and using video and power baluns. The camera wires run in wireways that are just packed with all kinds of other wires. There are high voltage power wires, signal cables, two large generators, thrusters. I'm afraid the shielding on the Cat5 is insufficient.

 

When both generators are running and the thrusters are running, I get massive interference on every camera in the engine room. Green tint, rolling horizontal lines, black outs, it's bad. We even went as far as to pull power from a 12v source close to the cameras, just to make sure voltage drop wasn't the problem (camera runs are 250 ft), no change. I can link photos and video of the interference if anyone wants to see it.

 

The boat that just left keeps having these issues, and they are not going to leave me alone until the issue is fixed. I have been reading about quad shielded RG6, could this be the solution to my problems? I am planning on testing the cameras with a test monitor to eliminate the cabling as a problem, and bringing some cameras from a different distributor to see if the interference is getting in through the cameras instead of the cabling. Pretty sure the issue is the lightly shielded Cat5 crossing over so many cables, though.

 

Too long didn't read, will quad shielded RG6 block most of this interference?

[survtech 0]

Camera cables should never be run close to high voltage cables. Although it is somewhat possible that more shielding would help, it is difficult to find quad shield RG-anything that has a solid copper center conductor and sufficiently low resistance in the shield for return. That affects the distance the cable can transport the signal.

 

One option is fiber. Optical Fiber transport, while expensive, is totally immune to electrical interference.

 

You also might try fully digital cameras (IP or maybe HD-SDI). Digital signals are relatively immune to noise and interference.

[Jburn 0]

Camera cables should never be run close to high voltage cables. Although it is somewhat possible that more shielding would help, it is difficult to find quad shield RG-anything that has a solid copper center conductor and sufficiently low resistance in the shield for return. That affects the distance the cable can transport the signal.

 

One option is fiber. Optical Fiber transport, while expensive, is totally immune to electrical interference.

 

You also might try fully digital cameras (IP or maybe HD-SDI). Digital signals are relatively immune to noise and interference.

 

Thank you for your quick response. So IP cameras aren't bothered by interference? That's good to know. I am trying to switch our camera systems over to IP for simplicity and ease of installation, but I was worried about the interference part.

 

As far as the cable being ran close to high voltage cables, we have no choice. The shipyard provides wireways for out cables, cable trays is what they are. But it's community space. That means that the DP guys run their cable in there, the Caterpillar guys run their cable through there, the thruster power, thruster controls, generator signal and controls.. It's a mess. We try to keep ours to one side, but we end up crossing over these other cables a lot.

[survtech 0]

Camera cables should never be run close to high voltage cables. Although it is somewhat possible that more shielding would help, it is difficult to find quad shield RG-anything that has a solid copper center conductor and sufficiently low resistance in the shield for return. That affects the distance the cable can transport the signal.

 

One option is fiber. Optical Fiber transport, while expensive, is totally immune to electrical interference.

 

You also might try fully digital cameras (IP or maybe HD-SDI). Digital signals are relatively immune to noise and interference.

 

Thank you for your quick response. So IP cameras aren't bothered by interference? That's good to know. I am trying to switch our camera systems over to IP for simplicity and ease of installation, but I was worried about the interference part.

 

As far as the cable being ran close to high voltage cables, we have no choice. The shipyard provides wireways for out cables, cable trays is what they are. But it's community space. That means that the DP guys run their cable in there, the Caterpillar guys run their cable through there, the thruster power, thruster controls, generator signal and controls.. It's a mess. We try to keep ours to one side, but we end up crossing over these other cables a lot.

Oh, they can be bothered, it's just that they're a bit more immune and the signal is typically go/no go; essentially it's either there or it's not.

 

Like I said, the only thing that would be completely immune is optical fiber.

[Jburn 0]

Camera cables should never be run close to high voltage cables. Although it is somewhat possible that more shielding would help, it is difficult to find quad shield RG-anything that has a solid copper center conductor and sufficiently low resistance in the shield for return. That affects the distance the cable can transport the signal.

 

One option is fiber. Optical Fiber transport, while expensive, is totally immune to electrical interference.

 

You also might try fully digital cameras (IP or maybe HD-SDI). Digital signals are relatively immune to noise and interference.

 

Thank you for your quick response. So IP cameras aren't bothered by interference? That's good to know. I am trying to switch our camera systems over to IP for simplicity and ease of installation, but I was worried about the interference part.

 

As far as the cable being ran close to high voltage cables, we have no choice. The shipyard provides wireways for out cables, cable trays is what they are. But it's community space. That means that the DP guys run their cable in there, the Caterpillar guys run their cable through there, the thruster power, thruster controls, generator signal and controls.. It's a mess. We try to keep ours to one side, but we end up crossing over these other cables a lot.

Oh, they can be bothered, it's just that they're a bit more immune and the signal is typically go/no go. Like I said, the only thing that would be completely immune is optical fiber.

 

But isn't HD-TVI digital? Wouldn't that qualify for less interference?

 

Every camera on the vessel looks fantastic, even these three. But when the generators and thrusters are turned on, these three specific cameras go crazy.

[survtech 0]

No, HD-TVI is analog, as is HDCVI and AHD. The only truly digital choices are IP and HD-SDI.

[survtech 0]

HDTVI - New Technology for IP & Analog HD Solution

[jazzar 0]

Ideal if you can separate the cable runs from all the other mains voltages.

Ideal if you can suppress all the electrical noise at the motors sources- is there any suppression devices- is the mains regulated -if so are they working ?

As indicated by others fibre being glass + light is immune to electromagnetic noise- but you need a specialist to fit it.

Ideal is a Bit difficult in your situation.

Using twisted pair cable works on the principle of the difference between the A wire and the B wires being processed and since these would normally pick up an equal amount of noise- when the control point then compares the difference you should be left with just the camera signal since the noise being even on wire A and wire B should cancel itself out.

To try twisted pair you need to use a pair of baluns for each camera (a tx unit and a rx unit) which take the bnc connector at one side and drive/receive twisted pair on the other side. If you use shielded twisted pair you should only tie 1 end to a common ground to stop earth loops -if you tie both ends to earth you could get an earth loop- not sure about earthing on a boat- but this is best practice on land.

You could try this on the worst one and see how you go- cheaper than fibre and more serviceable for onboard techs.

I don't envy you on this one- sounds like a real stinker.

If all else fails -Buy a new boat with the cctv working-- he ho.

[joseph.chen0312 0]

Yes, Fiber is best choice to immune from Electromagnetic but media convertor better use industrial type not normal one.

[ilk 0]

Yes, Fiber is best choice to immune from Electromagnetic but media convertor better use industrial type not normal one.

 

Agreed 100%

 

The correct solution will be multimode fibre utilising transceivers sourced from manufacturers who build for the transport sector.

 

These will be tested for vibration and fluctuations in power.

 

Try Comnet http://www.comnet.net/aboutus/its.html

 

Ilkie