Posts Tagged ‘ coaxial cable’



Security Camera Cables

Written By:
Friday, March 4th, 2011

If you have a “wired” digital video system, you’ll want to make sure you have the correct security camera cables for it.  In this article we’ll take a look at the most common type of security camera cable and its connectors.

Digital video security cameras generally require two types of cable; one for video transmission of the camera to the DVR (Digital Video Recorder) and one for the power supply for the camera from a power supply source.

The most common security camera cable used today is the RG-59/U.  This is a coaxial cable designed specifically for low-power video signals.   Historically speaking, the name of the cable originates from the U.S. military.  RG-59 designated the type of cable and the “U” stood for general utility use.  However, the “RG” (which stood for “Radio, General”) component is no longer part of military standards, however the name use has remained, generally without the “/U” designation.

RG-59 security camera cable has a unique characteristic that makes it a good match for use with video transmissions.  It has the same impedance as an antenna, such as the “rabbit ears” type that was used on televisions.  This impedance of 75 ohms makes the cable a good choice for radio frequency transmissions for televisions, DVRs, and security camera video.  RG-59 is smaller than typical cable television cable, RG-6, and is therefore less obtrusive and easier to manipulate.

However, RG-59 has a tendency toward high-frequency losses over long distances (greater than RG-6 for example) but 750 feet seems to be a generally agreed upon length before significant losses appear.  These can also be corrected with drop amplifiers or active (powered) baluns to boost signals.  For most security camera systems applications, RG-59 coaxial cable works well.

The RG-59 security camera cable consists of an outer plastic sheath (the colored cover or jacket of the cable), followed by a copper braid shield (it looks like a mesh or netting of fine wire), underneath which is an inner dielectric insulator (often looks like a milky white thick plastic material somewhat like a drinking straw) that contains a copper-plated or solid copper (better performance) center wire core.

RG-59 cable is usually fitted with one of three different types of connector; F connectors (used most commonly for cable television applications), RCA plugs (often used by DVD players), and BNC connectors.  By far the most common type of security camera cable connector is the BNC.

The BNC connector provides a means of connection for both the shield and core of the cable.  The connector has “male” and “female” plug types that when inserted together and twisted properly, stay locked together.  In fact “BNC” stands for the bayonet like locking mechanism (B), and Paul Neill (N) and Carl Concelman (C) it’s inventors.

Security Camera King offers three different types of BNC connectors based on how they attach to the RG-59 cable.  Connectors are fastened to the security camera cables either by twisting on, crimping, or compression.  Twisting is the simplest and requires no additional tools once the wire is stripped and trimmed.  Crimping, when done properly, generally holds the connector to the cable better but requires the use of a crimping tool.  The best connection that provides the greatest strength is the compression BNC and it requires a compression tool.

Security cameras also require a power supply cable.  This is normally standard 18 gauge copper wire with plastic insulation.  The power for most security cameras is low voltage DC current of 12 volts or low voltage AC current of only 24 volts and this wire is suitable for carrying the power supply of either.  The power supply cable that terminates at the security camera end usually does so using either screw terminals for each wire (often for AC) or a 2.5 mm female type power plug (often for DC) with a positive center.

Security Camera King offers complete security camera systems that include security camera cables for both power and video transmission.  We offer pre-cut lengths of video and power supply cable with connectors already installed for “plug n play” use.

For applications with differing distances of cameras from the DVR, we offer bulk Siamese RG-59/18-2 cable with twist-on connectors.  This cable consists of both the RG-59 video transmission cable and the 18 gauge 2-wire power supply cable.  One cable means one run per camera saving you time and work.

There also offer other types of less common security camera cables.  Check our Web catalog for more information.

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Outdoor Motion Activated Security Camera System

Written By:
Thursday, July 22nd, 2010

An outdoor motion activated security camera system is an ideal choice for perimeter coverage of a home or business. In addition, motion activation is a conservative, economical choice that produces excellent video surveillance and security results.

What exactly is an outdoor motion activated security camera system? The description sounds fairly complicated but in reality the system is relatively simple. Anytime motion is detected, the digital video cameras switch on and begin recording video images. So if no motion is detected, the cameras shut off. This conserves digital video file storage space on a Digital Video Recorder or DVR since the system only records when motion is detected.

Let’s take a closer look at an outdoor motion activated security camera system. These systems are similar to any other digital video security system in that they consist of one to several cameras, a processor/DVR unit, and a monitor. The camera produces an electronic image and sends it along to the processor/DVR. The processor reads the camera data and uses it to create a digital video file. The digital video file may then be viewed on a monitor and/or stored on the DVR for later use.

Most digital video security systems will record constantly, that is 24 hours a day, 7 days a week. However, an outdoor motion activated security camera system only records when motion has been detected. There are several advantages to this type of system.

Many digital video cameras today are wireless; that is they do not have a coaxial cable that transmits the video signal to the DVR. Instead, these cameras have a built in transmitter and antenna that they use to send the signal via radio waves to a corresponding receiver. The receiver then passes the signal electronically to the processor/DVR. However, these wireless cameras still need a wire for a power supply.

To avoid the necessity of a power supply line and transformer, digital video cameras have been manufactured that can utilize rechargeable batteries. A digital video camera with wireless video transmission and rechargeable batteries is truly wireless. This type of camera is incredibly versatile in that it can be mounted almost anywhere without the concern for any type of cabling or wire attachment. However, continuous video capturing can run down the batteries after several hours making replacement with freshly charged batteries necessary. An outdoor motion activated security camera system can greatly extend the run time of rechargeable batteries, because the camera only captures video when motion is detected. Although a very small amount of energy is needed for the motion detector, the largest amount of drain on the battery is during video capture.

Another advantage of an outdoor motion activated security camera system benefits the DVR. A DVR is basically the same thing as the hard disk drive on a personal computer. DVRs come in a wide variety of storage capacities ranging from gigabytes to terabytes in size. Still, digital video files can take up tremendous amounts of storage space, even when COmpression/DECompression utilities are used to make the files smaller in size filling up the storage disk in a short period of time. A motion activated camera only records when motion is detected, which means the DVR is not required to store video files for a continuous 24 hours, unless motion is present for all of that time. Recording video only when activated by motion can greatly reduce the amount of storage capacity needed on the DVR.

How do outdoor motion activated security camera systems detect motion? These cameras are connected to a special sensor called a Passive InfraRed or PIR sensor. When an object passes in front of the sensor, the sensor can detect the change in infrared radiation. A relay connected to the circuit board of the sensor then switches the camera on. Most cameras turn off either after the motion is no longer detected or for a specified time period after the motion is no longer detected.

Some examples of uses for outdoor motion activated security cameras include parking lot monitoring, building entrance and exits, pet monitoring, and perimeter monitoring of homes, yards, buildings, and industrial areas.

An outdoor motion activated security camera system can save time and money. It can enhance the use of wireless, rechargeable battery operated cameras and it can conserve DVR storage space for use when it is most needed.

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