daubs8 Posted May 8, 2009 Posted May 8, 2009 We changed a faulty monitor in a gatehouse 60m from the main building with a 17" flatscreen. The picture is rubbish, lots of interference. When we put an old CRT in the picture is fine? Possible causes? I am contemplating swapping co-ax for cat5. Thanks.
DannyTheTech Posted May 8, 2009 Posted May 8, 2009 We changed a faulty monitor in a gatehouse 60m from the main building with a 17" flatscreen. The picture is rubbish, lots of interference. When we put an old CRT in the picture is fine? Possible causes? I am contemplating swapping co-ax for cat5. Thanks. Hi Daubs, CRT monitors will display even the worst video signal as a very good sharp picture. However before i re-ran the cable i would have a look a the video level on a scope and make sure that its looking as is should (sharp lines and as close to 1v P2P as possible). You may find that the video level very poor and that somthing like re terminating the cable can push the level up enough. If not and you are still getting poor results then running CAT5e with balun would most prob sort it out. Having said that, IMO CRT's give a much better display and definition than LCD and the use of LCD can be detremental to the final install as you have a great image produced by the camera then you "slug" the final display by putting it on a poorer format. Usually for the sake of asthetics. (anyway im not going to get on this rant as ill be here all day) Hope this helps. Danny
breff Posted May 8, 2009 Posted May 8, 2009 Might be worth trying a video amp. I had a similar problem yesterday, camera approx 120m from dvr, monitor wanted approx 40m from dvr. I used the loopthrough on the dvr as the monitor is only to show a single camera, on my test monitor there was a beautiful colour image, when I fitted the TFT it was black and white. I decided to use the spot monitor output from the dvr and the colour came back. Turns out the video signal was too low after travelling approx 160m. The opinions I express are mine and are usually correct! (Except when I'm wrong)(which I'm not)
digitalwitness Posted May 8, 2009 Posted May 8, 2009 If you are splitting the main monitor output to two locations then it may be a termination issue, the CRT may be properly terminated where the LCD may not, normally not an issue until you split the monitor output with a properly terminated in parrallel with a one that is not. Have seen this with a few of the cheaper monitors.
SUBS Posted May 8, 2009 Posted May 8, 2009 Do the TFT and the CRT monitor both have 3 core mains leads, in other words is it earthed now, but wasnt before or vice versa ?
Selsport69 Posted May 9, 2009 Posted May 9, 2009 Got a similar problem now. Camera on a gate house cable runs about 60m back to the control room dvr. They wanted the gate house camera to show on a new monitor in the gate house. So we thought easy way to do this is a t-piece from the camera and take it back to the monitor direct with the other cable as is. Nope picture wobbles all over the place etc. Tried the video am dosent make it any different infact as we increase the gain the worse it gets. Its fine on either one monitor on its own but not 2. We are using the Fusion dvr. The monitor in the control is a LG flat screen as the Fusion gives us a vga output. The monitor in the control room is a Vista TFT. So open to suggestions. Kev
breff Posted May 9, 2009 Posted May 9, 2009 Ditch the t-piece and loop through the gatehouse monitor instead The opinions I express are mine and are usually correct! (Except when I'm wrong)(which I'm not)
MattBaker Posted May 9, 2009 Posted May 9, 2009 Ditch the t-piece and loop through the gatehouse monitor instead Just a quick thought, is the DVR on the network ? if so is the guardhouse connected on the network aswell. Can you see where i'm going here ? Remotely view the CCTV on the lan network, no more cable to pull in ! Matt
john@total Posted May 10, 2009 Posted May 10, 2009 Got a similar problem now. Camera on a gate house cable runs about 60m back to the control room dvr. They wanted the gate house camera to show on a new monitor in the gate house. So we thought easy way to do this is a t-piece from the camera and take it back to the monitor direct with the other cable as is. Nope picture wobbles all over the place etc. Tried the video am dosent make it any different infact as we increase the gain the worse it gets. Its fine on either one monitor on its own but not 2. We are using the Fusion dvr. The monitor in the control is a LG flat screen as the Fusion gives us a vga output. The monitor in the control room is a Vista TFT. So open to suggestions. We have found this on most sites we have upgraded a PDM mon from CRT to LCD. What you need is a 2 way video distributor at the cam, input from cam, x2 out puts to dvr and monitor. can get 12v 2 way VD so just install it in the gate house cam. john
SUBS Posted May 10, 2009 Posted May 10, 2009 Got a similar problem now. Camera on a gate house cable runs about 60m back to the control room dvr. They wanted the gate house camera to show on a new monitor in the gate house. So we thought easy way to do this is a t-piece from the camera and take it back to the monitor direct with the other cable as is. Nope picture wobbles all over the place etc. Tried the video am dosent make it any different infact as we increase the gain the worse it gets. Its fine on either one monitor on its own but not 2. We are using the Fusion dvr. The monitor in the control is a LG flat screen as the Fusion gives us a vga output. The monitor in the control room is a Vista TFT. So open to suggestions. As been said, forget the T piece, either loop through from monitor or the DVR whichever is nearest, and make sure you got the termination right, or fit a VDA. If you dont know what I mean about the termination- look, it aint brain surgery - get a CCTV engineer to sort for you.
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