Showing posts with label Video Loss. Show all posts
Showing posts with label Video Loss. Show all posts

Tuesday, December 2, 2014

Basic Things to Know About CCTV as a Technician

Some Basic Things to Know About CCTV as a Technician, If you are manager just share this with your team.

Cable Running
Many facilities use closed circuit television (CCTV) as part of an overall security system. Cameras mounted on buildings or ceilings transmit signals to a central monitoring room. CCTV takes two forms ---hard-wired or wireless. A technician just starting out in CCTV has to gain a knowledge base of how CCTV works, so he will be able to install, test and troubleshoot systems. Do not run 3+1/4+1 CCTV Cable, use RG11, RG6, RG59 only. Find-out the length of Video Cable from DVR to Camera, it should be on limit. Do not overlapping with High voltage wire. Do not join the Video Cable, use complete length ( One drum Video Cable its 305Mtr) of wire. If cable layed in out door use Armour cable.


RG 59 which can transmit signals up to 200 metres. This distances are for a single run of cable with no amplifiers or in-line correctors.

RG 11 which can transmit signals up to 270 metres. It is more expensive because it is thicker. This distance are for a single run of cable with no amplifiers or in-line correctors.

RG 6 which can transmit signals up to 400 metres. It is more expensive because it is thicker. This distances are for a single run of cable with no amplifiers or in-line correctors.

Twisted pair cable is a good alternative to coaxial cable if the length of the run is more than a few hundred metres. With pure cooper twisted pair, runs of up to 600 metres can be used without any in-line repeaters.

Troubleshooting Signal Loss
The picture on the monitor should never be fuzzy or have interference patterns. If it does, signal loss is occurring somewhere in the system. Technicians have specialized testing equipment and know how to use them in order to troubleshoot systems. Usually, a technician starts at the camera and works her way back to the receiver. She/he checks each connection until the test equipment indicates a loss. Some common problems are corrosion due to moisture inside the connectors or cables chewed through by animals.

Camera Installation
CCTV technicians can't be afraid of heights. Cameras are mounted high on the sides of buildings, or high in the ceiling areas of stores. You have to use a boom lift to reach spots to mount cameras. If you suffer from heights, becoming a CCTV Technician may not be a valid career path.
Cables are installed from the camera to the receiver station. You will have to drill through masonry block and below floor to run the cable. Be prepared to navigate through tight cramped quarters to get the cable from the camera to the receiver. Bring along a change of clothes, since you will get dirty in the process.

CCTV Camera Installation Tips:-
1. Test all equipment before installation. Therefore equipment can be replaced before arrival on-site if needed.
2. Ensure the mounting brackets of outdoor speed domes are properly sealed to prevent condensation in the camera housing.
3. Ensure sufficient space for camera, lens and connectors when choosing camera housing.
4. Avoid direct sunlight on equipment as it raises the temperature of the equipment.
5. Position cameras out of reach of vandals or 'curious' people.
6. Mount good quality mounting brackets in a stable location to avoid unstable or vibrating images caused by vibration or wind.
7. CS Mount cameras placed inside, at industrial or dusty/damp installations should be placed into outdoor camera housings.
8. Avoid installing cameras too high above the subject thus preventing 'top-of-head' video images
9. Ensure camera mounting poles are mechanically secure to avoid vibration on camera images
10. Before connecting power, ensure the supply is 12VDC regulated.

CCTV Cabling Tips:
1. Avoid running video cable parallel to AC power cables, especially those carrying high current.
2. RG59U Coax runs should not exceed 180m for colour and 280m for B/W
3.Avoid sharp bends when cabling
4. Avoid cable joins and using BNC barrels
5. Avoid over-tightening cable-ties
6. Ensure use of proper co-ax wire-stripping and crimping tools
7. Ensure BNC Connectors are properly crimped
8. Use Rubber BNC Boots after crimping to protect crimped area and bend radius
9. Mark or label camera and data signal cables
10. Outdoor cable runs should be housed in UV-proof conduit
11. In lightning prone areas, install surge protection devices

Final Testing and Teaching

A technician tests the system after it's installed. This involves knowing how to aim the cameras, knowing how to operate the monitoring equipment in the security room and knowing how to instruct the final operators of the system. You have to be part teacher. You may have to deal with people who have no knowledge of how a CCTV system is operated, so you have to use layperson-friendly language during the training process.

As you are a Engineer / Technician remember this few points:
Visually inspect all major components and connections for signs of deterioration or damage
Check all control equipment (DVRs, VCRs, monitors, multiplexers, video switchers, telemetry units etc) for correct operation
Check mains & power supplies and stand-by batteries including charging rates.
Check environmental conditions for adverse effects, including growth or shrubbery obscuring camera views
Check time and date settings in equipment and update the settings as appropriate
Check integrity of all cabling and sample check external insulation for damage
Clean cable fixings for security
Check auxiliary lighting equipment, infra-red units and photocells (if any) for correct operation
Check air vents are clear in all control equipment including PCs
Clean cameras, lenses and housing surfaces as necessary
Check al glands and seals on external equipment
Clean control equipment surfaces including PC (if applicable)
Establish regular back-ups are taken
Check camera is aligned to user specification, pictures for correct field of view and adjust as necessary
Check brackets, towers and fixings for corrosion or damage. Check clamping bolts/brackets are tightened correctly
Check wash/wipe units and wiper blades (if any) for correct operation and fill washer reservoir where necessary
Check quality of recording during day time and night time modes
Check pan and tilt assembly (if any) including fixings, electrical connections and functions.
Check the satisfactory CCTV transmission of images to remote site (if applicable)
Check warning signs are in place
Check all camera presets
Check all alarm presets