AHD CCTV is an analog high definition closed-circuit television video surveillance standard that uses coax cable to transmit HD video from security cameras to DVRs. AHD supports 720p and 1080p HD video resolutions.AHD stands for analog high definition. These cameras can support RG59 and CAT5 cable, but the cables have a low transmission distance. Coaxial cable (RG59) can reach up to 1600 feet but CAT5 can only reach 492 feet. AHD provide good pictures but the images are not as sharp and colors are not as accurate as TVI. AHD cameras have won in the price category, where prices are almost as low as analog cameras.AHD cameras do require a compatible HD DVR in order to capture high definition video.