RQ0261E Bad picture noise on AV In who can help

[monette]

Dear Forum, Sammy

I have a question to the forum.
I have two cameras installed with a cable lenght of 10m in my camper.
On for the reverse camera, where the picture is okay. The 2nd camera see picture ist waste water dump.

This camera shows diagonal lines. What can be the root for this issue.

AV Signal to low. Damping of cable?

How can I measure the signal amplitude to know what is going on.

Here a picture what is going on.

BR
Bob

[Jammy]

Hi,
About the display problem,it should be the camera problem.You can try to exchange the two camera.
About your another two problem,sorry ,i also don't know them.
Regards

[monette]

Dear Sammy thank you for your response.

I have tried another cam and it showed the same issue. I have a camper using a long cable.
Can be cable damping the root cause?

I have some technical questions.
What transmission protocol is the AV in using. Is it the Composite protocol?
What signal to noise ratio does the pumpkin AV in need to have a clear reception?

Can you ask the engineer what can be the root cause. Any other idea how to analyse the root cause.

Thank you

[barfly]

Monette-

You have noise induced by the length of the poor quality cable. To mitigate the problem get a good quality 75ohm co-axial cable, preferably copper and replace the thin audio cable with this new one. If you can't find suitable plug ends, just cut your old cable 3-4 inches from the ends and solder the two inners together, insulate with heat-shrink or good quality insulating tape (preferably self-amalgaming tape) and then the earth braid to the old earth of the original plug. That will fix it. Caravans and motorhomes have more problems because of the cable run lengths.

Another very common cause of induced noise, audio and video is after body shop repairers have replaced metal panels. They fix them with mastic sometimes to other plastic panels so are left with a floating earth. A simple fix is to use braid to earth all the metal body parts to their neighbour. This usually fixes a multitude of other problems such as one dim headlight, or winkers not working properly.

Hope this helps, Tony (tv engineer/electronics specialist).

[Jammy]

[monette]

Dear All & Barfly, thank you I will go with your proposal and purchase a twisted & shield cable with min 4 and shield.

Signal composiute
Signal GND
Shield (connect to signal GND)
and Supply & GND for 12V

I will use a twisted pair with an outer shield. hope that solves my issues.

Thank you BARFLY

Greetings

[monette]

[monette]

Dear Sammy

are the inputs of AV in & Cam in are having different filters? AV in shows noises effect and the reverse Cam In picture is okay.
I have the concern that the input filter of AV is not as good as for reverse cam in.

Thank you
monette

[barfly]

Dear Barfly
the funny thing is that only the AV in shows this effect and the reverse cam in picture is okay.

I have the concern that the input filter of AV is not as good as for reverse cam in.
This can be only answered by Sammy technicions

What cable do you recomend ? RG175??? or RG59 with a twin line for supply. On the RG59 I have the concern that noise & ripples will be coupled in over supply. IT is not shielded.

http://www.caledonian-cables.co.uk/Coax ... 75_AF.html
http://www.caledonian-cables.co.uk/Coax ... 59_F2.html

Thank you for your help.
monette[/quote]



Monette- I would always use RG59 for this application, you only need about 10 mtrs you said, so it won't be that expensive.

Have you tried swapping the inputs from the 2 cameras? If the reverse cam shows no sign of interference, but the waste does, that is a good diagnostic pointer. Most cheapie reverse cams have pretty ineffective led lights, that can give rise to horizontal line interference on the display at low light levels. That may be a contributing factor. Before doing anything else, get a bright light source onto the waste disposal area, and see what difference that makes.
Cheers, Tony.

[monette]

Hello Barfly,

I have hooked up the camera on a short cable the picture was perfect. I have tried two other cameras as well.
Same result.

If I am using a long cable all cameras a making issues. I assume the low cost cable which is in the pruchase included is not a coax neither twisted.

I will change the cable first.

Thank you
Bob