What is HD CCTV?25th August 2015
Any signal passing through a coaxial cable was considered analogue and signal passing through a network cable for ip cameras was/is hd.
The experts have been trying to invent hd over coaxial cable as this is more efficient, less costly option to upgrade as users would not need to change existing cables. Sometimes these cables are built into the infrastructure of buildings and replacing them is not an option.
So first came HD SDI. This technology allowed us up to 4 mega pixel on its cameras but was very problematic as engineers struggled with its lack of compatibility with older cameras and its demand for best quality copper core coaxial cable only or it would not work. Even the bnc connectors at the ends would cable could cause a nightmare for engineers.
Now we have hd tvi. This has truly shook up the market. HD TVI is a hybrid meaning you can add older analogue cameras to the same system as the new hd cameras. It also has the benefit of working on cheaper coaxial cable, in fact any coaxial cable that can carry the signal and give you the hd picture. Not only that, if network cable has been run for an existing analogue system, these cables can also be used by adding good quality hd tvi baluns. In my experience i have seen images from both network cable with hd tvi baluns and coaxial cable and i can say the coaxial cable is far superior.
One may ask why bother installing analogue in the first place if you got hd over network cable for ip cameras. Apart from the cost and the extra complexity to setup, the hd image you get from an ip camera carries a stature. In other words when you watch the 25 frames played to you in a second, you will notice a millisecond pause or transition to the next frame. This does not happen with analogue and AHD (hd tvi, hd sdi).
What is the best HD option for CCTV?
HD is when you are looking at dots not lines. It is a clearer picture. It is no longer restricted by cable type. Analogue HD exists and is very popular as its cheaper and more stable than the older ip hd cctv systems. Also with ip, if you do not purchase the same branded camera and nvr the two will have to be paired up. My advice go for hd tvi.
There is 4k cctv out there for the rich. I know very little about 4k cctv at present only that it is twice the sharpness of the best available hd picture. Will keep you posted.