View of the device

HDT-1F-EXT is a high quality balun adapting the impedance of balanced UTP line to the impedance of unbalanced input or output of a CCTV device, combining very efficient surge/overvoltage protection of the connected devices. Thanks to an autotransformer with amorphous core and linear characteristic up to 42 MHz, the device is specially dedicated for CCTV systems transmitting HD video signals (AHD, HD-CVI, HD-TVI), as well as can be used in CVBS systems.

The EXT (extreme) series uses the latest protection means in the form of superfast automatic fuse made in MOSFET technology. The special fuse has a very low electrical resistance during normal operation. When, due to an overvoltage, the current increases above 100 mA, in a very short time it automatically disconnects the line from the part of the protection circuit connected to the input or output of a CCTV device.

The built-in surge protection has three segments operating in the right order during lightning or other incidents of surges and voltage spikes of various levels. During normal operation, the video signal circuit is not galvanically connected to the ground, which eliminates harmful ground loops and the related interference.
An excessive electric charge is discharged to the ground in the initial stage of surge formation (at the rising edge), which lowers the overvoltage to a safe level. In order to discharge the surge current to the ground, the yellow-green wire should be connected straight to a good grounding system. Secondary overvoltages are eliminated by a separate circuit decoupled by a unique solution with the ultra-fast MOSFET fuse and transient voltage suppressor. This results in high durability and efficiency of the device, also in the case of multiple pulses.

The idea of the protection system

Very low capacitance of the protection circuits (4 pF) has a minimal effect on the video signal transmission within 0~100 MHz frequency range, which is especially important in the case of the broadband AHD, HD-CVI and HD-TVI signals

In order to ensure full protection, it is recommended to use the surge protectors and good grounding on two ends of the video transmission line. The application of HDT-1F-EXT device on one side will effectively protect only the neighboring device.

Example of a very effective protection of an HD camera and a receiver (monitor, DVR etc.)
connected via UTP line with the use of two HDT-1F-EXT M17027 devices

Example of effective protection of an HD camera and a receiver (monitor, DVR etc.)
connected via UTP line with the use of HDT-1F-EXT M17027 and HDT-1F-PRO M17012 devices