Wired camera signal doesn't work in different rooms - Page 1
Forum section: electronics / beginners

author: pogchamp
author_rank: Newbie
timestamp: January 09, 2021, 05:35:09 pm
content: So I am trying to wire a security system using FPV cameras and old monitors.This is the set up I am using:So the camera itself has 3 wires. +5v (red), data (yellow), and ground (black). The data wire outputs composite video (the yellow,red,white cables that go into a tv). I then use a little converter box that changes that into VGA, which then goes into the computer monitor.This works just fine when it's all in the same room. However, when I put the camera in a room quite far away from the display, it breaks.So this is the setup:The only difference here is that there are about 10 meters of additional signal cable between the camera and the box. And also, the camera is powered from the room it's in.I thought maybe the set up is not working correctly, but if I get another camera and plug it in the same room as the display, it works.I thought it would be that the signal cannot travel that far. But that's not the case. If I then add 10 meters of cable to the signal wire and trail it down the corridor the same way (I thought perhaps there was interference?), it still works:But if I connect that 10 meter wire to the camera in the other room instead of the second camera I was testing it on in the display room, it miraculously breaks.I know that the main camera works because if I put a second display in the room it's supposed to be in, it is working fine. But I want it to send that signal down the hall.It seems to be something to do with being powered from a different room. And I cannot figure out why.I know that sometimes electronics that are supposed to communicate get upset if they're connected to different grounds (LED strips in particular). Could it be something like that? Is there something really obvious I'm missing?Thanks

author: mikerj
author_rank: Super Contributor
timestamp: January 09, 2021, 05:50:15 pm
content: Do you really only have the single yellow wire connected to the video box, with no ground return? If so I'm amazed it works at all. You need a 75 ohm coax connection from the camera to the box, with the coax screen connected to the black wire at the camera.

author: pogchamp
author_rank: Newbie
timestamp: January 09, 2021, 06:09:46 pm
content: Quote from: mikerj on January 09, 2021, 05:50:15 pmYeah, single wire. The ground of the camera is just going into the ground of the 5v power supply.I've just tried connecting the negative of the camera to the negative of the RCA cable but it still isn't working. I'm going to keep trying with different cables in case I've made a mistake.Also to clarify, you're saying coax cable, but this is using RCA. I wasn't sure if there was a difference, so I googled it and it says that RCA is the connector type and is in a way a 'digital' coax cable, but perhaps I am mistaken.By the way, what do you mean by "with the coax screen connected to the black wire at the camera." ?Just to be sure, is this what you meant?So far it has not worked. The wires are like 1mm hobby wires, with thin coloured plastic insulation, which are connected to a stripped RCA cable.EDIT: It's working?? I didn't change anything... I guess the connections between wires was poor? I just kept trying different combinations of wires and it's now back to how it was at the start, only this time it works...

author: mikerj
author_rank: Super Contributor
timestamp: January 12, 2021, 10:27:56 pm
content: Sorry, forgot all about this. Yes that's what I mean, the black wire from the camera should be split to go to the battery negative and the coax screen.

author: Ed.Kloonk
author_rank: Super Contributor
timestamp: January 12, 2021, 10:50:19 pm
content: Use a video balun.https://www.kogan.com/au/buy/latestbuy-techbrands-video-balun-kit-300m-bnc-co-axial-to-cat5e6-utp-ahd-52029/?utm_source=bing&utm_medium=cpc&utm_campaign=Bing+PLAs&utm_term=1101400107879&utm_content=Ad+group+%231Run cat5 for the signal.