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DC power over coax

Pine Pienaar

Aug 1, 2016
3
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Aug 1, 2016
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I wish to provide DC operating power via the coax cable that feeds the video signal from a remote monochrome video camera. The required circuit is not complex but I have no idea of the frequency components in the video signal and hence the size of choke to use.

Assistance or a pointer in the right direction will be highly appreciated.

73 de Pine, ZS6GST
 

Audioguru

Sep 24, 2016
3,656
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Sep 24, 2016
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3,656
Doesn't an analog video signal need DC coupling for the proper black level?
Many, many years ago I used a DC-restorer circuit and a coupling capacitor.
 

Ylli

Jun 19, 2018
400
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Jun 19, 2018
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Base band video can go all the way from zero to multiple MHz, depending on the sweep rate. I don't think you are going to have much luck trying to feed the DC power down the line.
 

FuZZ1L0G1C

Mar 25, 2014
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Mar 25, 2014
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Hello Pine.
What connector does your video remote video camera use?
USB, AV with separate DC supply? DIN socket?
If you can supply a clear photo of the business end of the connector, then a solution will be easier to work out.
Regards, Clive.
Afterthought:
By 'remote', do you mean 'cabled' as in coax as mentioned (1 coax plug only) or RF link?
 
Last edited:

Pine Pienaar

Aug 1, 2016
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Aug 1, 2016
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3
Hi Clive,
The video output signal is via a BNC connector. I wish to run DC power for the camera down the coax while receiving the video signal via the same coax. I live in a high lightening region and have lost several cameras as a result of a loop being formed with the coax video cable and nearby camera power supply that is tied to the mains. By running one cable to the camera no loop able to pick up induced lightening spikes will be formed.
 

duke37

Jan 9, 2011
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Hi Clive,
. By running one cable to the camera no loop able to pick up induced lightening spikes will be formed.

I have repaired a few electric fencers which have been damaged by lightening. They only have one wire running into them. Of course a loop could be worse.
 

ramussons

Jun 10, 2014
462
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Jun 10, 2014
Messages
462
I wish to provide DC operating power via the coax cable that feeds the video signal from a remote monochrome video camera. The required circuit is not complex but I have no idea of the frequency components in the video signal and hence the size of choke to use.

Assistance or a pointer in the right direction will be highly appreciated.

73 de Pine, ZS6GST

Use a simple video modulator that shifts the video to RF. You can feed DC power to the Camera and the Modulator on the same coax
 
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