Frequently Asked Questions
Should I install a DVR or NVR?
NVR stands for network video recorder.
As the name suggests, these record images via a network using Cat5 or Cat6 ethernet cables.
The NVR system uses IP (Internet Protocol) cameras, these cameras capture digital Images at source and use the NVR for recording these images.
DVR stands for digital video recorder.
These record uncompressed images using coaxial cable, they compress these images to a digital signal to enable viewing on your devices.
The DVR system uses analogue cameras.
N.B. you can use ethernet cables with the addition of balun's instead of coaxial cable, but you will still only own an analogue system.
In the past the video quality of DVR systems lagged behind NVRs, today this gap is significantly less due to the advancement in analouge technology, this improved picture quality is achived at the sacrifice of realtime recordings, with most DVRs only recording at 12 FPS or less. Although this is still normally good enough for video playback in most applications.
NVR systems still have better picture quality and normally record at 25 FPS or greater, they have more flexibility and are more 'future protected' than DVRs.
In our opinion, we would install a NVR and IP cameras if you are installing a new system and a would only install a DVR with 2MP analouge cameras or greater if you are upgrading a system that is already cabled over coax to save the cost and labour of replacing the cables.
Do you really need 4K security cameras? Probably not!
A good rule of thumb is to use the right amount of resolution versus the purpose of the camera and not use the highest resolution simply because it's available.
If you want to capture number plates and recognise people’s faces, use a minimum of 2MP cameras for distances of upto and around 6 meters, but this calculation doesn't allow for the lighting, position of the camera and the angle of view which could all make reading number plates or identifiying people more difficult.
If you want to monitor a larger area of your property or identify number plates at greater distances, use at least 4MP cameras, using higher definition cameras may also require a higher definition DVR or NVR.
One of the main advantages of 4MP and greater cameras is the combination of larger field of view and better quality images, however if you just need to monitor a smaller area or somewhere close by, such as the entrance or approach to your property a 2MP camera is perfect.
In summary the the greater the number of megapixels, the larger the field of view and the better & sharper the images are, these can be 'overkill' if you are capturing something nearby.
What cameras should I install?
Your choice of DVR or NVR will decide if you need analogue or IP cameras. Following this you will need to consider the quality of camera you need, this is normally measured in image resolution or megapixels. Megapixels is actually a measurement of the quantity of pixels displayed in your image & not necessarily the quality of it.
So do more megapixels in a camera mean better image quality? Not always!
The lens choice, the quality of the components used in the camera, including the image sensors & image processors all play important roles in producing superior images.
If these components are equal in quality to the higher quantity of megapixels in your camera, the images recorded will definately be higher quality.
What cables should I use?
Analogue over Coax.
RG59 coax cable is the industry standard and the best choice for CCTV systems over coax, however, not all RG59 cable is equal.
Coax cable is available in 50 ohm, 75ohm and 93 ohm. The impedance of CCTV cameras is 75 ohms. So it is important to only use 75 ohm cable In order to have minimum video loss. (Impedance is a measure of resistance, in the cable).
Some RG59 coax cable, especially the ones used for Cable TV have a steel or copper plated steel conductor instead of pure cooper, steel has a much higher resistance than pure copper which leads to poorer image quality and/or video loss.
Steel costs less than copper, which makes this an attractive option for some installers who don't fully understand the implications of what they are installing.
Analogue over Ethernet with Baluns.
See Digital below for the overview on Ethernet cables.
These can be used with the addition of Baluns to transfer your analogue signal, the one downside of this method is the Ethernet cable is designed for RJ45 connectors and not a baluns, for this reason you may find that the wires are easily broken when connected to a standard balun, leading to signal or power loss. The upside to this type of cabling is that you are future protecting your installation should you be thinking of upgrading to an IP system in the future, Although we would recommend (budget allowing) you always install the latest equipment available.
What cables should I use?
Digital / IP over Ethernet.
There are lots of options when it comes to Ethernet cables:
Which version - CAT5, 5e, 6 or 6a, Shielded or Unshielded, Gauge, Stranded or solid, Cooper or CCA (cooper clad aluminium)?
In short, unshielded CAT6 with a solid copper core and a gauge of 23AWG is the best choice of Ethernet cable for professional security installers in most cases, but read on for the full explanation.
Shielding is used around each of the 4 pairs of cables within the Ethernet cable to further protect the cables from interference and is designed for use in areas with high interference, such as running cables along the same routes as electrical cables, along steel frames or metal clad buildings. For most installations we can choose routes that have minimal impact from these types of interference meaning the extra expense of sheilded cabled can be avoided. These cables are described as FTP - Shielded and UTP Unshielded.
The gauge of the wire is a measurement of it's conductors thickness and this is measured in AWG's.
A 23AWG cable is 0.57mm wide, while a 24AWG cable is 0.52mm wide, so the lower the gauge the thicker the cable, this is very important for your CCTV installation, as the wider the cable the easier it is for the signal to pass through it, meaning less resistance leading to less interference, better quality images and more fluent viewing, plus with thicker cables there is a lower risk of poor termination in the connectors and the cables breaking.
Stranded cable is more flexible and would typically be used at your desk or anywhere there may be potential of a lot of movement on the cable. Where as solid cable is not as flexible, but this means its more durable, which makes it ideal for permanent installations as well as outdoor and in walls.
Copper Clad Aluminium (CCA) or full copper cables? CCA cables are designed with an aluminium conductor at the core which is coated in copper. This production technique uses less copper, offering a low-cost way for companies to produce Ethernet cables, but what are the hidden costs? CCA cables do not comply with industry standard specifications, therefore officially there is no such thing as a CCA Cat5e, 6 or 6a cable, although they are advertised as these cables.
More importantly CCA cables are not designed to withstand Power Over Ethernet (POE), POE allows network cables to carry electrical power to power you cameras. If these cables are used for POE, the cables can overheat, with the initial temperature increase being twice the increase seen from a pure copper lead and if the cables contain stranded CCA conductors, the impact of the heating will be greater still, at best this may cause your CCTV to fail, at worst it's a FIRE RISK.
Also aluminium has a much higher resistance than pure copper which leads to poorer image quality, video lag and/or video loss. Plus, aluminium is also very reactive and is prone to oxidizing when exposed to air. This may cause failed terminations and broken wires and even without this issue the CCA conductors are brittle and break easily, the wires may break as a result of pulling or moving them, It’s also important to note that the bend radius of CCA cabling is limited, creating a higher risk of breakage during installation.
What lens do my CCTV cameras need?
What lens you need is determined by what you want to view, this is called the optical range and it's the distance at which detail can be captured. Not to be confused with the IR range, this is the distance that the Infa red night vision works effectively.
Below is an approximate guide to the optical range of different lens on a 2MP camera, this is the distance at which a number plate or a person should be identifiable.
2.8mm lens 3 meters : 3.6mm lens 6 meters : 6mm lens 10 meters : 9mm lens 12 metres
12mm lens 14 metres : 22mm lens 24 metres : 60mm lens 70 metres
For most homes a wide angle lens of 2.8mm or 3.6mm is more appropiate as you are only monitoring images in the immediate area and these lens also give you a greater field of view, avoiding the expense of needing extra cameras to give you the same coverage.
Although fixed and variable lens cameras once fitted have a fixed field of view, most systems allow you to zoom in on the image using your viewing device, this in simple terms is 'blowing up' the image and if done with lower definition cameras or zoomed too much, the image will start to pixilate.
You can see an example of a professional 2MP camera with its normal view and the image 'blown up' in the pictures above showing how good the image quality is at approximately 6 meters.
How does infra red work on my CCTV?
The ability to film in low light conditions or even complete darkness is essential for CCTV.
Most modern cameras have built in IR (infa-red) lights. Getting good qality cameras, with good quality components is important and always gives you better results in low light.
The infra-red light isn't visible to the human eye, however you will notice a ring of red dots / lights on most cameras when you look directly at your camera. The IR CCTV cameras change to black & white as light levels fall and the IR bounces off the first surface in its direct line of sight to reflect the infra-red light so your camera is able to see in the dark, so it's important not to obscure the view and keep your cameras clean. Spider webs have a habbit of appearing on your lens and it's important to keep foilage cut back etc.
If you have motion floodlights in your garden or street lights outside, these will all help improve your images.
How does motion detection work with CCTV?
Motion detection recording is a feature on most DVR and NVR recorders. The recorder monitors camera images and decides if there is movement. To do this it reviews individual image frames and compares them to the previous frame, if it sees differences then motion is assumed to have taken place. It is the recorder and not the camera which is looking for movement.
The recorders aren't as intelligent as humans & can't differentiate between background movement, changes in light or someone coming to break into your home. To help minimise false triggers it's possible to select areas on the screen to detect movement, you can set up the trigger areas by navigating the menus on the DVR / NVR.
Some people only record footage when motion is detected in an attempt to extend the length of time their footage is stored. We are not in favour of doing this as it's better to install a larger memory and use motion triggering to create bookmarks within your 24/7 recording, using it to identify which sections may be important but still have constant footage.
Operators who use only motion detection are usually trying to compensate for too little memory. We recommend allowing a minimum of 500GB of hard drive space per camera which should give you about 2 weeks footage based on Cameras up to 5MP & you will need to consider using 1TB per camera if you're installing 4K cameras.
What size memory do I need & how many days footage will I have?
Modern CCTV Systems store their footage on an internal hard drive similar to computers, but DVRs and computers are different. Unlike a computer, your DVR is designed to run 24 hours a day with a continous data transfer. For this reason it is important that your hard drive is specifically designed for CCTV systems rather than standard computer drives which have a tendency to fail prematurely.
There are a number of factors that will determine how many days footage your CCTV hard drive store.
The main things to consider are:
Higher definition & quality Images will use more memory meaning less footage, for example a 4MP camera will use twice the memory versus a HD 1080P (2MP) definition camera. It is possible to lower the recording quality of your recordings to increase your saved footage i.e. a 4MP camera could be set to record at 2MP, but we would always recommend you consider a larger memory rather than sacrifice your image quality.
The number of frames per second you record will effect the amount of memory used, your recorder will have a default setting and this can normally be amended. If you record at 25FPS this would give you approximately twice the recording compared to recording at 12FPS. However you would loose 13 frames of detail in your recordings. 'Realtime' is 25 FPS and you should ideally be aiming for this as a minimum.
Each camera you have on your system requires space for its footage to be stored. Two cameras will take up twice the storage versus one camera, three cameras will take up 3 times the storage versus one camera and so on.
We recommend a minimum of 500MB per camera, which should give you about two weeks footage based on a HD camera with around 2MP to 4MP quality, meaning a two camera system will have 1TB hard drive to give around two weeks worth of footage, a four camera system will have a 2TB hard drive and so on
What is a PTZ camera?
PTZ stands for pan, tilt, zoom.
A PTZ camera can be remotely controlled allowing it to move up, down, left, right and zoom in & out.
In theory PTZ cameras sound great, they can cover large areas and even zoom in when more detail is required.
Rather than using a PTZ camera, consider fitting extra fixed cameras. For the same cost as a single PTZ camera you will normally find multiple fixed cameras will offer better value and give greater coverage.
PTZ cameras do have their uses but in the vast majority of cases you are better off using more fixed cameras.
The downsides to PTZ cameras are that they are expensive, certainly the good ones. There are plenty of low quality products on the market aimed at the DIY market, but these should be avoided. The biggest problem with PTZ cameras is that you need a full time operator to control them, otherwise when you leave them looking in one direction they will miss what happens in the other direction.
When remote accessing PTZ cameras to operate them, there can be a delay between you asking a camera to move and seeing the result of that movement on your remote monitor or computer. This is known as latency and it can make it difficult to accurately control PTZ cameras remotely over the internet.
What happens if my cameras film my neighbour's property?
Can I film the public space outside my house?
New legislation came in to effect on the 25th May 2018 and this effects everyone who already has CCTV installed or anyone considering installing CCTV. You can refer to the Information Commissioners website for more information.
The main considerations are as follows :
If your camera covers, even partially, any areas beyond the boundaries of your property, such as neighbouring gardens or the street and road, then it will no longer be exempt from the Data Protection Act (DPA) under the Domestic Purposes Exemption. This does not mean that you are breaching the DPA but it does mean that you might need to take some steps to comply with it.
If you are recording and storing data on property not owned by yourself, you are considered to be a Data Handler and as such you need to store and use this data in a responsible manor, not keeping it for longer than is reasonably reqiured.
You need to display signage stating that CCTV is being used, the purpose of its recording and who is responsible for the CCTV if it's not obvious.
It is fairly straight forward to comply with this legistation and you shouldn't be put off owning a CCTV system if you believe you have a requirment to install it, but make sure you are aware of your legal responsibilities.
Wireless CCTV cameras
In theory, wireless CCTV cameras offer the perfect solution, no cables to run, easy & quick installation, with very little mess & disruption.
So why don't we Install wireless CCTV?
Before you buy a wireless CCTV camera system read the information below and do your own research on the internet.
There are a number of problems with wireless CCTV :
Firstly they aren't actually wireless, you still need to power the cameras, normally by plugging them into the mains. Meaning you are restricted to mounting your cameras near a socket and for external cameras you will need to drill through your wall with holes large enough for the power leads to pass through. Be careful not to drill through your electrical cables drilling that close to a socket!
Wireless cameras also tend to be fairly poor quality aimed at the DIY market. The components aren't great and you only have a limited choice of lens options.
The wireless connection often causes problems. In the UK lots of other devices share the same frequency bands used by your wireless CCTV, items like routers which stream the internet around your home, microwaves, portable home telephones, baby monitors and bluetooth devices etc. In addition to these items, walls & other solid objects can also interfere with your CCTV signal, which is normally required to stream 24/7 and needs a constant uninterupted connection.