Guest tanknet Posted June 21, 2004 Posted June 21, 2004 Hi Chaps, 1st post (Glad I found this place) we are new in the cctv business (Qwik run I hear you shout) and I have basically been giving the task of installing camera's and DVR's. Now the DVR is no problem as I have a PC background. We have just installed a system in a school and seem to be having a few problems. 1) We have a camera (vantage Dome) point to a door with a window - unfortunatly mid day the sun can cause such glare that the image is unviewable. Have played about with contrast etc on dvr and can get a better picture but it is darker. 2) Would you use External Domes outside?? Yes I know the word external sort of gives it away but have never seen domes used. 3) There seems to be a haze on some of the pictures. sorry all the info I have at the mo as I am going on site tomorrow. 4) I have a couple of pics that jump. Any idea's 5) Thanks for any help. Paul
TSS Posted June 21, 2004 Posted June 21, 2004 check all cameras are on the same electrical phase, as this can make some pics scroll. Some more expensive cams (Baxall in particular) have a phase adjust pot on the back/side, this can cure that, else use a ground loop isolator or humbug. sounds like you are using cheap internal dome cams, get a proper one with back-light compensation, that'll cure the reflected light probs. external domes for outside? pre-requisite, need to be waterproof and have heater/blower or will mist up! If you are a gardiner Security customer ring their helpline (number inside catalogue) and get Vicki or your area rep to come and speak to you before you plan your next project! Good Luck... Hope this helps TSS Communication is "A question asked, and an Opinion given." I offer mine to help you with yours. Statements I make are my personal views only at the time they are posted, if I offend you sorry, must be taken in context and do not neccesarily represent those of my employer.
CompostCORNER Posted June 21, 2004 Posted June 21, 2004 Is it a fixed dome camera? If not, sun glare is a side effect you will get with any PTZ dome camera if the camera is looking into the sun. If it's fixed, could it be positioned higher up to avoid the sunlight blindng it? How about changing it for a conventional camera with a sun guard. Jumping pictures could be caused by several things. Inadequate power, too much power. Ensure the correct voltage is being supplied and make sure the PSU is regulated. Dodgy connections and crimps can cause problems too. I've found out the hard way over the years that supposed CCTV engineers still have problems making decent and correct BNC crimps. Different phases for each camera could be an issue too. You could temporarily disconnect the earth to the cameras if they are mains fed. Remember though, this is strictly for testing only and the earth MUST be replaced when you have finished testing. Alarmbloke mentions adjusting the phase pots. This is great to syncronise the pics through a switcher and on to the monitor. This stops pics rolling as they change from one to the other. It's worth trying that to remedy your picture rolling. Hazy pics.... Incorrect cables can cause this. Even the regulation RG59 coaxial cable can cause haze due to the fine detailed information signal degrading over long distances. How long are the cable runs? Are the cameras properly terminated? The most common fault on CCTV installations is simple incorrect termination. Tony
Guest Secure Eng 1 Posted June 22, 2004 Posted June 22, 2004 A good solution for cameras looking at windows or glass doors is JVC's new WDR (Wide Dynamic Range) camera. Click-through to the demo system on our website to see one on same application as a standard camera with BLC (Back Light Compensation) switched on. WDR works much better. It is made for this application, and it's not expensive. For outdoor domes; some of the vandal-resistant versions perform well and are quite cost-effective. Vista's VVRD4C9 delivers a good colour camera, with a 4-9mm vari-focal, auto-iris lens, in a vandal-resistant, weatherproof housing - ideal for school applications. NB the heater is an optional extra with this model, not always necessary. Haziness - could it be that you've fitted cameras into outdoor housings with heaters and not pre-heated them ? Sometimes the housing heaters cause a heat / chemical haze on the inside of the housing window when they first heat-up; best to 'burn them off' in the workshop before installing - freezer spray again !!
Rich Posted July 13, 2004 Posted July 13, 2004 Hi Tanknet 1) We have a camera (vantage Dome) point to a door with a window - unfortunatly mid day the sun can cause such glare that the image is unviewable. Have played about with contrast etc on dvr and can get a better picture but it is darker.For any camera covering an area that involves sunlight should be fitted with an auto iris lens, Im presuming the vantage dome is one of the small type board cameras that have no settings to twiddle, Could the problem also be light reflecting on the inside of the dome cover? I'd have to agree with Secure Eng 1 and use something like Vista's VVRD4C9 cameras for situations like that.2) Would you use External Domes outside?? Yes I know the word external sort of gives it away but have never seen domes used. External domes are usually ready for external use, the camera and lens combination would have some sort of auto iris and if you are going for budget stick to mono cameras, Also bear in mind that large areas of grass will flare up more due to the IR emitted from the greenery. Basically the camera will be standard but the dome housing will be externally rated, ie IP65. this means that its protected from water/dust, weather etc. 3) There seems to be a haze on some of the pictures. sorry all the info I have at the mo as I am going on site tomorrow.The haze could be due to signal loss down to too long a run of cable, It could also be a lack of light in the area its covering. depending on the type of camera, the shutter speeds, auto electronic shutter would be helpfull to play with.4) I have a couple of pics that jump. Any idea's If you have the cameras looping through different items of equipment then you may need to look into termination, multiplexers with a throughput usually have either a 75ohm termination jumper, or auto termination, depending on equipment. Also its good practice to leave the display setting as they are, dont try and make good a poorly set up cctv system with the monitor. And when installing internal cameras next to windows etc, try and put the natural light source behind the camera instead of directly at it whenever possible. One last thing, when setting up external cameras, use a high density filter/dark sunglasses if setting the cameras up during daylight to mimic nightime, there is a fine line for setting here and if you dont set up your cameras for night and day, you will most likely get called back because the cameras are totally out of focus at night. Sorry my 2 pence worth is late, I have only just joined too Good Luck Rich
Guest tanknet Posted July 13, 2004 Posted July 13, 2004 Rich, Thanks for the info - Must have popped back 4 times already to the job anyhow. - Hopefully they are happy now. They still dont like the grainy picture on the live tft screen - have told them its the agc circuit kicking in and that the recordings are a lot clearer.
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