Testing CCTV Analogue Cable

[leachim 0]

I have a long stretch of monitor cable - probably 140 metres (2 sections - centre signal with earth braid - and also 12v positive and negative)

No signal is getting through to the monitor

It used to work

Cable has been up 10+ years

Have tried various modalities like cleaning contacts

Latterly have disconnected both ends of the video cable - then joined the earth braid and live together at one end

Went to the other end and used an ohms meter to check the reading over approx 280m  (2x140m) - by one probe on the signal centre and another probe on the earth braid- it was 15 ohms

Now, is that what you would expect over that run of cable ?

Thanks

[zapdivvy 0]

I detached the video cable from both ends, united the earth braid, and moved in with my partner at one end. I went to the other end and checked the reading with an ohms meter across a distance of around 280 meters (2x140 meters), and it was 15 meters. Is that what you would anticipate across that cable run, then?

drift hunters

[tomcctv 190]

18 hours ago, zapdivvy said:

I detached the video cable from both ends, united the earth braid, and moved in with my partner at one end. I went to the other end and checked the reading with an ohms meter across a distance of around 280 meters (2x140 meters), and it was 15 meters. Is that what you would anticipate across that cable run, then?

 

All this to post a signature ADD 

you don’t even have a clue how to use a multimeter 

[leachim 0]

On 4/28/2023 at 4:29 AM, zapdivvy said:

I detached the video cable from both ends, united the earth braid, and moved in with my partner at one end. I went to the other end and checked the reading with an ohms meter across a distance of around 280 meters (2x140 meters), and it was 15 meters. Is that what you would anticipate across that cable run, then?

drift hunters

Not sure what planet you are on, or what you are smoking...

What's the point in half quoting my initial query and then messing it up ??


Anyway, anybody got an answer for my original question from March 5th ???

[tomcctv 190]

4 hours ago, leachim said:

Anyway, anybody got an answer for my original question from March 5th ???

Hi what is your coax running … camera feed or dvr feed to your monitor

doing ohms test will show nothing you need a bnc 75ohm resistor plug at one end

but 450ft of coax and power will not run anything at that distance 

[leachim 0]

Coax is running camera feed.

Other part of the cable is the 12v feed.

Used to work fine, but am worried the cable has broken down....

Don't think there are any resistors in the connectors.

[tomcctv 190]

Hi this is more likely to be a power problem 

what amp is your 12v power supply

[leachim 0]

2 hours ago, tomcctv said:

Hi this is more likely to be a power problem 

what amp is your 12v power supply

It is from a box of multiple power outlets

Have a look at the pic

 

[tomcctv 190]

Ok 12v 5amp total 🟰 0.5 amp each

this is pushing you power to the limit if not over

12v 0.5amp can not go 140meters (450ft)

voltage and current drop 

 

but that power supply is adjustable and you can get 14v out of it  which is why it worked 

and it’s not allowing that voltage anymore …. You can try altering the voltage again by turning up the yellow voltage pot  indicated we’re it says 12 adj (hole next to it)

but you are under powered and you always have been for 140 meters

are you in the uk

[leachim 0]

1 hour ago, tomcctv said:

Ok 12v 5amp total 🟰 0.5 amp each

this is pushing you power to the limit if not over

12v 0.5amp can not go 140meters (450ft)

voltage and current drop 

 

but that power supply is adjustable and you can get 14v out of it  which is why it worked 

and it’s not allowing that voltage anymore …. You can try altering the voltage again by turning up the yellow voltage pot  indicated we’re it says 12 adj (hole next to it)

but you are under powered and you always have been for 140 meters

are you in the uk

Yes in Devon

To be fair, we have a camera on FURTHER 50 m than the camera I am on about, and the image is dodgy, but works

Have tried a separate 12v ps in the camera, and still no joy - measuring 12v when plugged in

Also tried a separate camera with the same connections and no good.

Got to be the coax ?

This is what I did initially :

"Latterly have disconnected both ends of the video cable - then joined the earth braid and live together at one end

Went to the other end and used an ohms meter to check the reading over approx 280m  (2x140m) - by one probe on the signal centre and another probe on the earth braid- it was 15 ohms"

Is that good or bad ??

[tomcctv 190]

52 minutes ago, leachim said:

Have tried a separate 12v ps in the camera, and still no joy - measuring 12v when plugged in

That would not help …. Your original power supply may have been set to 14v ….. it’s adjustable 

12v 0.5 amp can’t work at your distance 140 meters to run a camera ….. it is not possible 

you don’t seam to be looking at amps 

 

as far as your ohm readings …. It’s pointless 

you will get different readings down to make of cable … how attached 

this is a 75ohm terminator that you put on one end of coax and then ohm test for 75ohm

 

now for the distance your talking about ….. cat5 with baluns should of been used  

as far as power supply  I would go 24v then knock down to 12 at camera end 

 

and another give away is the camera you have at 190meters is poor …… which also should be done in cat5

[leachim 0]

I used a separate 12v power supply at the camera end to no avail

So it has to be the coax ?

We had a nightmare running the coax 140m through ducting, attics, roofs of buildings, between telegraph poles to get it where it is !

Laying a cat5 similarly is daunting !

OK, There is wireless internet at the camera end   (not same wireless that is near the Hikvision box in our house)

Could I obtain a wireless camera and then somehow tell the Hikvision box to communicate with it..... ?

[tomcctv 190]

So you have power and internet at both locations 

 

while using 12v at camera end (12v what amp ?)

what voltage are you getting at dvr end coax ?

[leachim 0]

On 4/30/2023 at 10:56 AM, tomcctv said:

So you have power and internet at both locations 

 

while using 12v at camera end (12v what amp ?)

what voltage are you getting at dvr end coax ?

I used this at the camera end