Interference on a short-run (<8 meters).

[mastertheknife 0]

I have 2 identical cameras i bought from ebay about a year ago. These have 520TVL Sony CCD inside them.

Few days ago i decided to install the 2nd camera (was unused all this time). connecting it to the DVR or TV with a short cable yields great picture.

I mounted the camera at its target location (under a metal roof) and ran temporary cables (12VDC power and RG59 coax, both less than 8 meters) to inside the house.

The temporary cables don't go anywhere near fluorescent or AC cables. the minimum distance from AC is around 30 centimeters.

 

I was getting extreme interference (rolling lines at AC frequency) at first but then isolated the camera from the metal roof by using spacers and it solved the problem. However, i'm now\still getting a different type of interference. a less serve interference and seems to be diagonal.

I tried re-doing the connectors and using different 12VDC power supplies. No luck.

Its important to note that the DVR is actually a PC and is using the same power outlet as the power supply.

The metal roof is grounded, i'm not sure at which point, but when measuring with my multimeter the metal roof to ground, its definitely grounded somewhere.

 

Here is a picture of the interference (the camera on the right is the one) - click to zoom:

 

mastertheknife.

[mastertheknife 0]

2. the power you use is not enough to support it.

 

Not possible. My power supply is 10A 12VDC and only the camera is connected. Voltage is 12.7V. I also tried 13.5V but no difference.

Power cable is 14 gauge.

 

mastertheknife

[rory 0]

Ive seen that with power issues before also, bad cable or too thin, eg. using telco wire to power a camera over 50' or so.

You say its 14 gauge so that counts that out, maybe its just a bad camera.

Have you tried another camera at the same spot?

Also try powering the camera locally at the camera location to be sure, anything is possible.

[mastertheknife 0]

Ive seen that with power issues before also, bad cable or too thin, eg. using telco wire to power a camera over 50' or so.

You say its 14 gauge so that counts that out, maybe its just a bad camera.

Have you tried another camera at the same spot?

Also try powering the camera locally at the camera location to be sure, anything is possible.

 

Yes. I tried the camera next to the DVR prior installing it at the current location. It worked nicely.

Also, when plugging the camera to the TV, this interference is still there, but less noticeable.

I tried powering the camera at the spot with a different power supply (12VDC 1A), same issue.

 

I'm leading to think its interference from the metal roof or something, and perhaps the pieces of paperboard i used to as temporarily isolation from the metal roof are the problem, although it did good job in solving the rolling lines (from bottom to up at AC frequency)

 

mastertheknife

[rory 0]

Try a local plastic shop and have them cut a square piece of thick plastic (to match the color of the pole). Make sure the screws are not long enough to go through that and touch the metal and also recess the screws that hold that to the metal and fill the top of that recess hole with caulk, this way making sure no part of the camera comes into contact with the metal at all.

 

Also check the Camera's cable, if its a bullet or dome make sure its not kinked coming out of the camera.

[mastertheknife 0]

There are no screws at all at this moment. the camera is simply tied strongly to the metal roof.

[mastertheknife 0]

Also, the cable is not kinked. I tried playing with the cable but no difference.

 

How likely is it to be the cable?

[mastertheknife 0]

Here are pictures of the way the camera is currently mounted (click to zoom):

The DVR is right after this window.

 

mastertheknife

[Nimrod 0]

Well i will state the obvious here. Multiple 12 vdc cameras on a single 12vdc supply. Sure sounds like a ground loop issue. Try using a separate 12 volt supply to each camera. Or disconnect one camera at a time and see if the interference goes away.

[mastertheknife 0]

Well i will state the obvious here. Multiple 12 vdc cameras on a single 12vdc supply. Sure sounds like a ground loop issue. Try using a separate 12 volt supply to each camera. Or disconnect one camera at a time and see if the interference goes away.

 

Hi, the other camera has its own power supply, soo each has its own power supply actually. I tried swapping the power supplies but no difference.

Disconnecting the other camera from the DVR doesn't solve the problem

[rory 0]

at this point I would take it down and plug it direct into the DVR and see how it is again. During installation anything can happen. One time I installed a dome camera, i put my portable monitor on it and it was fine, took it on and off a few times as I moved it around and then finally installed it in place. But the BNC got stuck, had a hard twist to get it off - I didnt think anything of it as that has happened many times before with different BNCs, DVRs and Cameras - but when I powered up the DVR that camera was blank - turns out the twist broke or damaged the inside of the camera's BNC cable end, thats how cheap that camera was ... I spliced on a spare BNC end I had and that fixed the problem. So yep anything is possible.

 

And oh yeah, though it voids your warranty, I would cut that power end off and splice it together direct, just us some wire nuts.

 

another thing, that power wire looks like high voltage wire? If so it can be picking up something, try using some 18awg instead, or lamp cord wire.

[mastertheknife 0]

at this point I would take it down and plug it direct into the DVR and see how it is again. During installation anything can happen. One time I installed a dome camera, i put my portable monitor on it and it was fine, took it on and off a few times as I moved it around and then finally installed it in place. But the BNC got stuck, had a hard twist to get it off - I didnt think anything of it as that has happened many times before with different BNCs, DVRs and Cameras - but when I powered up the DVR that camera was blank - turns out the twist broke or damaged the inside of the camera's BNC cable end, thats how cheap that camera was ... I spliced on a spare BNC end I had and that fixed the problem. So yep anything is possible.

 

And oh yeah, though it voids your warranty, I would cut that power end off and splice it together direct, just us some wire nuts.

 

another thing, that power wire looks like high voltage wire? If so it can be picking up something, try using some 18awg instead, or lamp cord wire.

 

Hi thank you i will try that.

No its not a high voltage wire (running it like that would be dangerous!). Its just 12VDC. the power supply is behind the window next to the DVR. This is ~14 gauge and is probably an overkill for this but thats what i had in the backyard.

The cables are currently going through a mess and through the window because the existing hole is full and this is reinforced concrete (30-40cm) so drilling a new hole requires a professional so until then its through the window :/

The cable is RG59 (not the foil type one) and the connectors used are 75ohm BNC from valley-ent: http://www.valley-ent.com/pics/S1B12.jpg

 

Also, theres something funny about this camera. I can't remove the stand without cutting the video and power cables. If i cut those, can i solder a new coaxial (with female connector) cable from inside the camera or is there a better solution to this?

 

Thanks again,

mastertheknife.

[rory 0]

Yes you could splice a new BNC to it, or just join it direct without a connector.

Having the connector is easier for maintenance and adjusting the camera .. and warranty .. but occasionally it has to be done.

[Campbell 0]

I know you were doing it on the cheap... but that mount job is making me cringe.. A LOT!

[mastertheknife 0]

I just tried something.

 

I removed the cable from the electrical duct (had nothing inside except cat5 ethernet, rg59 and 12vdc) and its now running directly from the window to the camera.

 

The interference is now almost non-existant. I guess the cable is bad and picking up interference.

 

mastertheknife

[mastertheknife 0]

I know you were doing it on the cheap... but that mount job is making me cringe.. A LOT!

 

Its pretty strong and long-lasting actually. Although at first i only considered it a temporarily solution, the other camera is mounted like that for about 1-2 years now without any removal or re-tightening.

The cable is a ~12-14 gauge solid core and is hard to bend.

 

mastertheknife

[rory 0]

just spray it all the color of the fence and beam

[mastertheknife 0]

just spray it all the color of the fence and beam

 

hehe.

Need to replace the coax cable with new, attach a small plastic box behind the stand to make the connections inside (this way its weatherproof) and run a PVC between the box and the electrical duct

 

Also, is a dome camera more suitable for this location? Its less visible and can be mounted nicely (with simple drilling to the top of the metal roof).

 

Also, this is the image from the camera after relocating the cable out of the electrical duct. Looks similar to other (identical) camera.

 

mastertheknife

[Campbell 0]

I know you were doing it on the cheap... but that mount job is making me cringe.. A LOT!

 

Its pretty strong and long-lasting actually. Although at first i only considered it a temporarily solution, the other camera is mounted like that for about 1-2 years now without any removal or re-tightening.

The cable is a ~12-14 gauge solid core and is hard to bend.

 

mastertheknife

 

Oh I have no doubt it serves its purpose and does it well. But from an professional installing point of view...

[Tailbone215 0]

Oh I have no doubt it serves its purpose and does it well. But from an professional installing point of view...

 

I have to agree! There are an infinite amount of mounting possibilities in this situation to make a better install with less effort. Hell, a couple self tapping sheet metal screws work wonders.