Interference On Cheap Cctv Cable

[nintenbo]

hi all

I brought a couple of small day/night CCD domes from............. yep you guess it Ebay. actually not bad at all but notice slight wavey lines and the more detailed the image the worse the waves are.

the cable ive used is not coax, as i thought i may as well take advantage of the free AV Lead (RCA)all in one as it come with it i thought it should work fine altho i had reservations due to its size of 4 cm dia.

ive now used coax to test and found no interference

you are prob thinking well "you had a problem, You've found the solution?"

yes but ive already installed one camera and rather not re-run in coax and seperate power.

any ideas what you may do in this situation

i thought hum bar rejecters but thats just for mains?

[Alarm Protection]

I always use 2 core belden and coax seperate. You can use shotgun cable also.

The cheaper he cabl then.............you know the answer.

Where are you taking the power from and what are you using??

[lawandorder]

hi all

I brought a couple of small day/night CCD domes from............. yep you guess it Ebay. actually not bad at all but notice slight wavey lines and the more detailed the image the worse the waves are.

the cable ive used is not coax, as i thought i may as well take advantage of the free AV Lead (RCA)all in one as it come with it i thought it should work fine altho i had reservations due to its size of 4 cm dia.

ive now used coax to test and found no interference

you are prob thinking well "you had a problem, You've found the solution?"

yes but ive already installed one camera and rather not re-run in coax and seperate power.

any ideas what you may do in this situation

i thought hum bar rejecters but thats just for mains?

My initial thoughts are that the power supply is not very well regulated.

The ac component in what should be a dc supply is being induced in to the video. Try running the camera using a battery of the correct voltage and if this cures the problem invest in a better quality supply.

Hope this helps.

[nintenbo]

so with out a fully charged 12v battery i used and old but better quality 12 v mains supply and.............................. Works perfect !! no interferance so i will change the power supply.

So luckly i dont need to undo my handy work too soon

thanks very much you saved me alot of time

guys

[lawandorder]

so with out a fully charged 12v battery i used and old but better quality 12 v mains supply and.............................. Works perfect !! no interferance so i will change the power supply.

So luckly i dont need to undo my handy work too soon

thanks very much you saved me alot of time

guys

Glad you got it sorted.

Never underestimate the value of good power supplies!

[SUBS]

if you can, try disconnecting the LEDs. even in daylight I'v had similar problems. some cheap LEDs radiate for some reason I dont understand.

Its most likely caused by the camera only having 3 wires, ie. the -ve is the same wire as the Video ground, and on a long (high resistance ) cable this inroduces a ripple onto the video signal.

Try it with a battery as close to the camera as you can get, if that cures it see if you cant fit a PSU nearer. and if you have more than 1 camera from the same PSU, try disconnecting some, sometimes you get crosstalk from HF ripple which the PSU cant decouple properly.

Board cameras are designed to be as small as possible, and decoupling capacitors are comaratively large items, so a compromise usually has to be reached somewhere.

My experience with cheap ebay cameras, is that they last all of a month or so, sometimes failing with a burnt PCB, so make sure they are fused, and be wary of the free PSUs that come with some of them.

[ICEbear]

if you can, try disconnecting the LEDs. even in daylight I'v had similar problems. some cheap LEDs radiate for some reason I dont understand.

Its most likely caused by the camera only having 3 wires, ie. the -ve is the same wire as the Video ground, and on a long (high resistance ) cable this inroduces a ripple onto the video signal.

Try it with a battery as close to the camera as you can get, if that cures it see if you cant fit a PSU nearer. and if you have more than 1 camera from the same PSU, try disconnecting some, sometimes you get crosstalk from HF ripple which the PSU cant decouple properly.

Board cameras are designed to be as small as possible, and decoupling capacitors are comaratively large items, so a compromise usually has to be reached somewhere.

My experience with cheap ebay cameras, is that they last all of a month or so, sometimes failing with a burnt PCB, so make sure they are fused, and be wary of the free PSUs that come with some of them.

Respect

[nintenbo]

can disconect the leds without de soldering,

so just when i thought the problem was solved you've hit the nail on the head SUBS, i only checked the day images and they was very good but on looking and the night time image the Interference has come back and im sure its worse? as the LEDs are on. ps cant disconect the leds without de soldering,

so i will need to get even closer to the camera at night and try with a battery. with all this in mind ive already ran coax and seperate power in the form of an 4/8 core to the cameras . never had problems with that before!

moral of the story "its too good to be true"