Im having problems with 12v cameras, not working. I recently installed some covert cameras from system Q, the 2 furthest cameras from the power supply will not transmit the video signal back to the DVR, I have placed the cameras on my test monitor at the camera end whilst running on the main power supply and they are transmitting a picture, however when i go back to the DVR there is no picture.

• The distance is under 100m and i have other cameras running at the same distance at other sites,
  
• The power is being transmitted down cat5e using one pair.
  
• The same power supply is also powering a couple of other cameras which are working fine
  

COULD IT BE THE CAMERAS ?

There is no local 240v to plug a local transformer into so I have to send the power the full distance.

The voltage at the transformer end is above 12v but at the camera end is below 12v

does anyone have a solution for me???????

if you got spare cores, double pos and neg up

missed that by seconds

Great Minds

Yeah ive got some spare pairs will try that.

At that kind of distance i would always run another cable for power say 8 core and double up all the cores, or even .75 twin flex.

Taylormade

If you are still having problems then up your PSU to a 2amp or a 4amp to really be on the safe side.

Good luck

Kev

If your PSU is adjustable you could send a higher voltage, 18Vdc say, and rely on the transmission loss to drop it to within acceptable limits at the load. That will only work, though, if there is no current demand fluctuation at the load. Otherwise, Ohm's Law applies and the resistance of the cable, being inversely proportional to the cross-sectional area and directly proportional to the length, is your problem. As others have said, use all the conductors you have available. Upping the capacity of the PSU to a higher amperage will only have any effect if the source voltage is too low due to excessive current demand. It will do no harm, though.

There are such things as voltage sensing PSUs where a monitor wire runs between the source and the load, monitors the voltage at the load and dynamically jacks the source up to compensate for the drop. They work with variable loads very well. However, I am not aware of a manufacturer making a PSU of this type for this industry. That's not to say nobody does, it's simply that I don't know.

you could send 24v from the origin, and at the camera end have a 24 to 12v regulator feeding the camera

Im having problems with 12v cameras, not working. I recently installed some covert cameras from system Q, the 2 furthest cameras from the power supply will not transmit the video signal back to the DVR, I have placed the cameras on my test monitor at the camera end whilst running on the main power supply and they are transmitting a picture, however when i go back to the DVR there is no picture.

• The distance is under 100m and i have other cameras running at the same distance at other sites,
  
• The power is being transmitted down cat5e using one pair.
  
• The same power supply is also powering a couple of other cameras which are working fine
  

COULD IT BE THE CAMERAS ?

There is no local 240v to plug a local transformer into so I have to send the power the full distance.

The voltage at the transformer end is above 12v but at the camera end is below 12v

does anyone have a solution for me???????

Maybe i've picked this up wrong by some of the answers but i take it you are using baluns to send the picture back along the cat5?

Seems if your getting a picture out of the camera onto your test monitor ok then the baluns or connections may be faulty as they should work ok over this distance or failing that you could try "Active (powered) baluns" or a line amp to boost the signal back along the cat5 to the DVR.

Only thing is you'll need to 12v them too

I would double up the cores for the 12v anyway and possibly try a 13.8v PSU if it's close on 100m run over cat5.

HTH

Seems if your getting a picture out of the camera onto your test monitor ok then the baluns or connections may be faulty as they should work ok over this distance

I see what you're saying but I've had similar troubles before where some units are pretty strict on the levels it receives and others aren't. I'd perhaps try the test monitor on the DVR end of the cable to rule this out, perhaps on the loopthrough on the DVR if it has one to prove it's actually going into it in the first place.

As you say, wouldn't hurt to double up on the power on that distance anyway, and maybe stick it on its own PSU rather than using a shared one.

We had a problem like this a few months ago using video baluns with cat on arun of about 200m our psu was at the camera.

Turned out we had to fit video amps back at the DVR. I blame cheap video baluns.