1. What is the difference between Analog, HDCVI, TVI and AHD?
|720P/1080P specification supported||25fps||25fps||25fps||25fps||25fps|
|Primary Cable Type||Coaxial||Coaxial||Coaxial||Coaxial||Net|
|Transmission Distance||Coaxial Cable (RG59)||300m/500m||300/500m||300/500m||300m||N/A|
|Twisted Pair (Cat5/e)||200m w/balun||200m w/balun||200m w/balun||200m w/balun||100m|
|DVR Input Compatibility||Analog||Support||Support||Support||Support||N/A|
|IP||N/A||All channels convertible to IP||On selected channel only||On selected channel only||Support|
|Format Compatibility||Open standard, mainstream technology used by all manufacturers, reaching
the end of product lifecycle
|Proprietary technology with outstanding R&D and expanding product
range, supported by world recognized manufacturer – Dahua
|Open standard, currently supported mainly by Hikvision||Open standard, currently supported mainly by Hikvision||Open standard under ONVIF, many manufacturers|
2. How do I choose the correct camera for my application? (Type, Indoor/Outdoor, Lens, IR)
Wired vs Wireless
One of the most common questions asked is about wireless camera. Everyone wants to have a wireless camera. While wireless cameras in the movies make people think that there’s such thing as a completely wireless camera system, in reality the wireless camera still requires a power source. Basically, a normal wired camera will need 2 cables, 1 for video transmission and another for power. Wireless camera is able to transmit the video wireless through WiFi, but it will still need power cabling. Hence, if it’s not entirely wireless, unless there’s a power source close to the wireless camera, otherwise cabling is still a necessity. Other than that, lost signal, dropped signals or worst yet lost video is possible with wireless camera. Unless it’s necessary to use wireless camera, otherwise wired camera will still be the better choice.
Indoor vs Outdoor
With all the choices of cameras out there, when considering a security camera, one of the first things is to understand where the camera is going to be installed. Dome cameras are common for indoor application and it is smaller and more lightweight. Bullet cameras are designed for outdoor application, typically made with more durable materials like metal, or even housed in an outdoor casing in order to discourage easy removal.
Depending on the purpose of the camera, there are generally 2 ways in judging a need for higher resolution camera. We often ask our customer if they need to identify or just to clarify, if the camera is installed in a premise to monitor the staffs or perhaps maid, the familiar faces is easily clarified by recognizing the hair style or clothing and so on, thus a lower resolution camera is still acceptable. If the purpose of the camera is to identify the facial feature of a stranger in order to facilitate investigation for the police authority, then a higher resolution camera is highly recommended. Besides, a higher resolution camera is also commonly deployed to capture details of the smallest varying shapes and colors such as money in the counter for retail stores.
Infrared or commonly known as IR is a light source generated by the camera that can be seen by the camera lens but not the human eyes. Comparing to the white led light, infrared is very efficient on power thus it can be powered by extra low 12VDC voltage. CCTV cameras are required to function 24hrs throughout the day and night, therefore energy efficiency is not only crucial for the lifespan of the camera, but at the same time cost effective for owner as well. The footage captured with an IR camera will typically be black and white.
Depending on where the camera is located, it is vital to understand the lighting condition exposed to the camera. Standard surveillance cameras (without WDR) will have difficulties in scenes with different lighting contrast. As an example, camera installed in indoor focusing on the outdoor area will have a light exposure problem.
The image on the left shows the details that were lost in the darker environment, such as the bike and also the person standing near the corner. The image on the right shows the missing entrance that was overexposed.
Both images lack the full information of the contrasted lighting condition, thus a WDR camera can capture these two extremes in a single image. It clearly shows the details in both the bright entrance as well as the dark indoor environment.
When choosing a CCTV camera, the lens sizes is often avoided due to common standardization (3.6mm). Serious consideration should be taking into account during selection of cameras. While a short focal length (eg: 2.8mm) provides a wide angle view, while the viewing angle is larger, the objects are smaller, suitable to be used for office with low ceiling height. On the other hand, a long focal length (eg: 12mm) gives a narrow angle of view, meaning the viewing angle is reduced but the image is zoomed in, thus a lot more detail for one area is achieved at the cost of losing a wide angle view.
3. Why do I have a clear sharp picture during the day and it is out of focus at night?
If you have such a problem, then it’s probably the IR LED’s quality, as well as the CCTV camera’s IR cut filter’s fault.As mentioned in the previous post, infrared or IR LED illuminates the area when the environment is dim or low in light source. The cameras supplied by Belco is equipped with a CDS sensor that detects the quantity of light. When the sensor dictates that the light source is low, then the camera board will be instructed to turn on the infrared LED. However, the IR LED’s quality is very important. Generally, the coverage of IR is within 15m. On top of that, all our CMOS chipset cameras also come equipped with high quality IR cut filter as well. Meaning that our cameras can see details in great clarity at night.
4. What is the maximum distance I can run 12vdc when powering a camera?
Typically, the recommended distance is within 30m with aluminium VDE cable, 50m with full copper VDE cable. Ultimately it depends on the resistance of the cable used.
5. How do I choose the correct power supply for my CCTV camera? (explain also DVR has its own power supply, do not share)
Depending on the model of the camera, please refer to the wattage or also abbreviated as (w) required by the camera. Volt multiply by ampere results in wattage, or v*a = w. Standard cameras require 12v, thus if the spec sheet indicates that the camera requires 4w, meaning that 12v*a = 4w, or 4w/12v = a, therefore the camera requires 0.33a. As a rule of thumb, it’s almost safe to assume that each camera requires 1amp or 1a. Therefore, when you purchase a power supply, if you plan to have a 4 camera system, simply get the 4a power supply. It’s also safe to get a higher amp power supply as it won’t damage the equipment.
The higher range power supply comes with a metal casing as well as PTC fuse board. As an example, PSD12095A power supply provides 12v, with 9 individual channels protected by PTC fuse, with a total of 5a, suitable to be used for a 4-8 camera system. Nonetheless, please take note that each PTC fuse comes with a 1.1amp rating, meaning that each channel is limited to 1.1a output, therefore it’s not recommended to use this power supply for your recorder.
6. Do I need a backup power for my CCTV system?
Like any other equipment that requires electrical power, in the event that there’s a power outage, the CCTV system will also cease to operate because there’s no electricity. Therefore an uninterruptible power supply such as FORMULA80 or S100EL is recommended for the recorder. On the other, PSB series power supply with a 12v 7Ah backup battery is suggested for the camera’s use.
7. Do I need to purchase a lightning/surge protection for my CCTV system?
Complete lightning isolation for your CCTV equipment is recommended, but it’s quite costly to implement a full range lightning protection.
MDSC0039(5A) protects your recorder as well as your power supply from the 230VAC plug point. In the event that there’s a frequent fuse box trip when it’s raining, then it’s highly recommended to get this lightning isolator.
MD-BNC-0E protects the coaxial cable from lightning. Each camera requires 2 units of MD-BNC-0E, reason is because the the coaxial cable is wired from the camera to the recorder. When lightning strikes, there’s a possibility of it going both ways, hence if the lightning isolator is only installed on the camera end, then the recorder will be jeopardized. Vice versa, if the MD-BNC-0E is only installed on the recorder end, then there’s a chance that the camera will be damaged. All in all, if the camera is exposed to outdoor weather, or requires underground cabling, then it’s highly recommended to install lightning isolator the camera and the recorder.
DCJ-cu(12V1A) protects the VDE cable from lightning. DCJ-cu(12V1A) is installed on the camera end to protect the camera from being damaged in the event that the lightning strikes from the VDE cable.
It’s best to consult our sales consultant’s advise for the most appropriate use of the lightning isolator.
8. What is a ground loop?
An AC current that can be produced in a cable. This is usually caused by parts of the system being fed from different electrical sources resulting in different earth potentials at each end. The result is interference on the signal, usually in the form of dark bands across the monitor and on occasion tearing in the top third of the image.
9. How can I eliminate ground loop faults?
This can be achieved in a number of ways, the easiest of which is the installation of a Ground Loop Isolation Transformer. This is best installed at the monitor or recording end of the system.
10. What type of video and power cable I should use for CCTV Camera? (explain also about full copper power cable vs normal ones)
It is common to find cables that are made of either aluminum (LC) or full copper. While aluminum oxidizes readily when exposed to air, copper also oxidizes when exposed to air, but to a much lesser extent. Therefore, A128 full copper coaxial cable and VDE100BC full copper VDE cable are more recommended for concealed cabling. Should there be any problem in the future, concealed wiring requires more effort to conduct another wiring session.
11. How do I choose the correct Hard Drive size?
Traditional, desktop hard drives are made to operate only for 8 hours a day and 6 days a week. So, the overall work load will be at the most 10%-20% and their performance will be low to moderate.
While a surveillance hard drive forms a central component to the digital storage of surveillance video. It can be used in a DVR, NVR, Video Server or a Video Management System in order to work 24 hours a day and 7 days week.
WD Purple drives have been engineered specifically for surveillance, so they’re able to withstand the extreme heat fluctuations and equipment vibrations within an DVR environment. An average desktop drive is built to run for only short intervals, not the harsh 24/7 always-on environment of a high-definition surveillance system.
As a rule of thumb, a 720P camera with continuous recording using 25fps setting will consume 16Gb/day. 1080P camera with 12fps require 21Gb/day, lastly 1080P camera with 25fps require 42Gb/day. As an example, if you have a 4ch 720P system, 16*4 = 64Gb/day, thus if you have a 1000Gb Hard Disk Drive, it will record around 14 days (24/7).
Please kindly consult our sales to help calculate the appropriate hard disk required for your system.