300m x 300m (1000' x 1000') Fence how to secure

[kao193 0]

Dear Experts,

 

First of all thank you for your past posts, I found this forum invaluable and full of useful tips. Keep up the good work.

 

I have been asked to supply a CCTV system to secure a 300m x 300 m fence against intruders from outside.

The offices where the control room is located are roughly in the middle of the yard and are 10m x 10m

Fence height is 4.5 m and there is some lighting at night (floodlights).

The area is generally remote and outside traffic is minimal. Yard contains large fuel metal tanks.

 

Being a non specialist (electrical power engineer) I read around the subject and so far came the following conclusions:

 

1- Wireless system (which is my preferred option) is not suitable due to the distance between the control room and cameras (over 200m) and the fact that no internet is available.

2- I will need to use a wired DVR system with either RG6 cable or UTP + active Balun. (please advise which is more suitable and easier to install)

3- I will need to use outdoor weatherproof static cameras with IR & motion detection capabilities but I am not sure about number of cameras required, mounting height, pointing direction and whether I need lenses.

 

The site is in Africa, temp is around 50 deg C and atmosphere is generally dusty & dry.

 

Feel free to recommend makes & models.

 

Many thanks

Khalid

[jhonovich 0]

If you are looking to secure the facility from outsiders and want alerts if someone crosses the fence, you are likely going to position cameras on the perimeter.

 

With a 300 x 300 area, I would use 8 cameras on the perimeter. 2 cameras for each side, mounted on the middle of each side, with one camera pointing right and the other left. This will divide the coverage into ( 8 ) 150 meter zones.

 

You may also want to consider using 1 or 2 PTZs positioned inside the facility looking out towards the perimeter to track suspects when alerts are generated.

 

I don't see a problem using wireless. 200m is not a problem for wireless (assuming you don't have obstructions - e.g., buildings or trees in the way). Whether not you should use wireless is a factor of how difficult laying new cable is. Wired is generally preferred because it is certainly more reliable. However, if you need to be trenching, you may be forced to go with wireless.

 

The key challenge here with the motion detection is how many false alarms you are willing to tolerate. Smart cameras that generate low false alarms are usually expensive (2,000 USD or more).

 

I will leave it at that to start. Please let me know what questions or feedback you have.

 

Best,

 

John

[kao193 0]

If you are looking to secure the facility from outsiders and want alerts if someone crosses the fence, you are likely going to position cameras on the perimeter.

 

With a 300 x 300 area, I would use 8 cameras on the perimeter. 2 cameras for each side, mounted on the middle of each side, with one camera pointing right and the other left. This will divide the coverage into ( 8 ) 150 meter zones.

 

You may also want to consider using 1 or 2 PTZs positioned inside the facility looking out towards the perimeter to track suspects when alerts are generated.

 

I don't see a problem using wireless. 200m is not a problem for wireless (assuming you don't have obstructions - e.g., buildings or trees in the way). Whether not you should use wireless is a factor of how difficult laying new cable is. Wired is generally preferred because it is certainly more reliable. However, if you need to be trenching, you may be forced to go with wireless.

 

The key challenge here with the motion detection is how many false alarms you are willing to tolerate. Smart cameras that generate low false alarms are usually expensive (2,000 USD or more).

 

I will leave it at that to start. Please let me know what questions or feedback you have.

 

Best,

 

John

 

 

Dear John,

 

Thank you for taking the time to respond to my post.

I have submitted my design before seeing your post but below is a brief outline.

I have used 4 x Bosch Autodome 500i PTZs with 36 zoom one at each corner (Bosch product no VG4-514-ETS)

I have opted for Pole (roof) mounting (Bosch item no VG4-A-9230). As this will mount the cameras above the fence and enable the cameras to monitor both outside & inside yard (although strictly inside is not a requirement).

Cameras have advanced features including motion detection, guard tours & auto tracking (check autodome on youtube).

 

Re your design

-------------------

I can see the wisdom of using 2 camera /side pointing left & right as this will avoid duplicate coverage. One of the options I offered was to use 3 fixed cameras (Swann Maxi) per side going into a clockwise direction. So thanks I will bear this in mind next time.

 

Re Wireless

--------------

You are right, there are systems upto several kilometers but initially I thought wireless referred to Ieee 802.11g systems. Later on I came across 900Mhz & 5.8GHz systems offered by AvalanWireless and Radio Contact from UK (rdcon) which provide both Line of site & Non LOS systems for up to several kms.

However the presence of large fuel metal tanks can bounce back the signals and hence I am not sure if this will work.

 

 

Transmission Distance

-----------------------

After much research I concluded that max distances per transmission medium are as follows:

RG- 59 cable is suitable for distances upto 800 ft or 250 m

RG-6 not sure but more than RG-59

RG-11 For distances upto 2500 ft or 800m

Twisted Pair up to 3000m (up to 20 km with repeaters) however max resolution can only be 400TVL

Microwave 1km to 30 km depending on how powerful the sender is

 

 

Further questions

---------------------

- I am looking for good quality & value 330ft infra red illuminators any recommendations are welcome.

- If I use an NVT balun and UTP cable with a non IP camera can I still transfer video & PTZ control (pelco compatible)?

- Other than safety are there any advantages in using 24V instead of 230V (our equivalent of your 110V)?

- The autodome has Lens with 36x Zoom (3.4 –122.4 mm) F1.6 to F4.5 What should be my default setting?

- I think I will need some sort of conduit to protect the cable running along the chain link fence, any recommendations would be appreciated.

- The cameras have a guard tour feature what are the best settings / duration to utilize this option.

- Is there a good book/course you would recommend If I need to learn more about CCTV system design (site survey, location of cameras etc..)?

 

Many Thanks,

Khalid

[jhonovich 0]

If you are using PTZs, how will you know when "intruders from outside" cross the perimeter.

 

PTZs are valuable for operators to control manually and scan an environment. However, they are very poor when it comes to generating real time alerts when someone crosses the perimeter. I do not think 4 PTZs are enough, even if you fix each PTZ to look down one side of the perimeter. You also run the risk of the PTZs being moved away from the perimeter and you missing an alert. Also, motion detection in PTZs is generally not that good (especially from Bosch).

 

If you really want to know when intruders cross from the outside, I think you have to use fixed cameras with analytics designed for perimeter violation.

 

Please let me know what you think.

[Thomas 0]

If you are using PTZs, how will you know when "intruders from outside" cross the perimeter.

 

PTZs are valuable for operators to control manually and scan an environment. However, they are very poor when it comes to generating real time alerts when someone crosses the perimeter. I do not think 4 PTZs are enough, even if you fix each PTZ to look down one side of the perimeter. You also run the risk of the PTZs being moved away from the perimeter and you missing an alert. Also, motion detection in PTZs is generally not that good (especially from Bosch).

 

If you really want to know when intruders cross from the outside, I think you have to use fixed cameras with analytics designed for perimeter violation.

 

Please let me know what you think.

 

You can do some tricks with using PTZ's to zoom using presets but that almost always requires having some fixed cameras supporting them as well, and low end software generally doesn't support rules management.

[zmxtech 0]

you should add some microwave long distance perimeter detection. because you wont have enough cams

[MattFisher 0]

Two solutions come to mind for perimeter fence detection with CCTV.

 

(1) Fixed cameras with Motion Detection. (Not my preferred option)

The number of cameras required, placement and lens selection (vertical angles of view) are critical in the design phase to ensure that the entire fence line is covered. Often there will be vulnerable areas along the fence unless you overlap the field of view of each of the cameras, for example the area directly underneath and adjacent to the camera pole. Then the nuisance alarm rate of outdoor motion detection needs to be considered. What is acceptable to your customer?

 

(2) PTZ cameras with alarm presets and fence alarm devices (My preferred option)

There are a couple of fence alarm systems that offer detection zones, acoustic, such as E-flex / Guardwire (ok for chain mesh fences) and Fibre optics, such as Future Fibre Technologies (best for most types of fences). These systems often have a low nuisance alarm rate. The alarm detection zones are then set up with the presets on the PTZ cameras to look at the area of fence in alarm.

 

If you have chosen PTZ cameras then you will need to look at option 2, of course you could also use outdoor beams inside the fence line instead of fence alarms, my preference is a purpose designed fence alarm system particularly the fibre optics.

[MattFisher 0]

RE: IR illuminators, (I cannot post links yet) these are nice.

 

extremecctv(dot)com - dark sky friendly products - Super LED range. 175m and 300m.

 

since you are using dome PTZ, I guess you'll have to set these up to look along the fence line. Sometimes best if using PTZ cameras and IR illumination to use the "old school" PTZ heads so that the illuminators track with the camera.