Cabling is straightforward, the CCTV camera requiring only a 12v power supply and an output composite video feed
Cabling is straightforward, the CCTV camera requiring only a 12v power supply and an output composite video feed.
We have operated meteor monitoring cameras with cables up to 10m in lenght without encountering problems but this will depend on your particular circumstances such as the model of CCTV camera and any local sources of electrical noise.
To minimise the number of cables, video and power in a single cable can be used for the video feed and camera power supply. However, the switching of the heating element can generate noise which interferes with the operation of the camera and causes UFO detect to generate false video clips. Therefore:
CCTV cameras will use 12v supplies at, typically, less than 1A and so only a small PSU is needed. Heating elements will use considerably more than 1A and it is especially important to ensure that enclosure PSU is matched to heating element.
Some enclosures use a 24v or even 240v supply; for safety we do not recommend using any enclosure that requires 240v, and in any case, providing safe external mains supply increases complexity and installation cost.
Mains powered 12v supplies are available from suppliers such as Maplin or RS Components.
To keep power consumption to a minimum, the enclosure heater and CCTV camera should not be powered up in the daytime. This is especially important for the CCTV camera as the iris must be closed in daylight to protect the CCTV from damage. The simplest option is to use timers on the 12v supply.
Several of our installations use mains powered 12v supplies which are controlled by simple timer switches used normally to switch on and off domestic lighting. It is important to ensure that:
The Hampshire Astronomy Group has implemented an innovative solution for its two Clanfield stations. These stations use a pair of light sensitive switches that switch off power in daylight; these switches operate in series so that if one should fail their CCTV cameras are still protected from damage from the Sun.
The weatherproofing of your enclosure will depend on effective seals. Enclosure provide a "gland" through which cables can pass and which provide an effective seal. This is perhaps stating the obvious but BNC video connectors can be large and may not pass through the gland. It may be necessary to fit connectors after cables have been passed through the gland.