A DPDT switch would enable you to switch both the camera supply and the video signal, to save power and avoid possible conflict.

Alright here I attached the said proposed diagram.

In short, at one moment, only one camera gets 12V DC and its signal wire gets connected to the TV.
And, the other camera has no power supply and its signal wire is disconnected to the TV.
NOTE: The 2 in 1 RCA splitter is no longer necessary here.

When CCTV1 is ON, its video signal by default remains connected to the input video signal wire of the TV.
And, at the same time, the CCTV2 is OFF, and its video signal wire remains disconnected to pin 87 of the DPDT relay.

When CCTV2 is ON, the reverse thing happens.
Its video signal gets connected to pin 87 through to the input video signal wire of the TV.
And, at the same time, the CCTV1 is OFF, and its signal wire gest disconnected.

Is the proposed wiring diagram feasible in the long run? Please help more on this.

 

Hi Tonsing,
Are the two CCTV cameras Indoors or Outside, where are they located?

E
I used a module of this type to select a camera.
https://www.google.com/search?client=firefox-b-d&q=two+relay+module

 

Their location doesn't play a FACTOR here.
Very silly questions

 

Hi,
I find your response offensive.!

I found if an outside mounted camera was left unpowered for periods of time it suffered corrosion problems due to condensation, also the lens tend to mist over as it warmed up.

By keeping it powered, the low level internal heating help protect the camera from moisture problems.

 

The length of the video cable matters because it has an effect on the higher frequency portions of the video signal. The higher frequencies carry the finer details of the image. At least in analog video. I have not studied how that works with digital video.
Of course, the quality of the cable also affects that loss per unit of length. It may not be obvious with the short cables used for connecting the cable box video to the monitor three feet away, but a 50 foot run from an outside camera it will be obvious.

 

just wondering how a DPDT switch could manage that.

By not switching the ground connections. So, one pole for the supply positive, the other pole for the video (providing its a single channel; not RGB on separate channels).

 

Their location doesn't play a FACTOR here.
Very silly questions

See post #25! the location does not matter, but the length of the video cable certainly DOES MATTER. And, as mentioned as well, the ambient temperature can be an issue as well. Parking lot security cameras usually have an internal heater for that reason.

 

Hi tongsing,
I have 4 Security cameras that have been working for many years, 2 in doors and 2 outdoors [under a covered area].

I quickly found out that the outdoors cameras, when powered off when not in use, caused problems with damp, moisture and condensation.
I now keep them continuously powered and over the past few years I have had no repeat of the problems.

E

 

So, in this link, whenever the switch is selected to switch the cameras, does it use relays? When switching takes place, does it power off the other cameras and also cut off the video power wires? Or it cut off the video power wires? What is actually inside this black box? Please kindly elaborate .

My best guess is electronic switching which really matters not. I have seen similar used in commercial applications and those were all solid state.

Ron

 

ALSO! It is simpler to only switch the video signal and leave the power on. PLUS, if the cameras have that little red LED indicating that they are active, that might deter some "bad actors" before they go any farther. AND preventing condensation is certainly a benefit.

 

For a system with only two cameras, it does not make sense to do all electronic switching. I have a few 16 line electronic switchers.they use diode switching. But I have not needed to use 16 cameras, or even three.