DIPOL Weekly Review – TV and SAT TV, CCTV, WLAN

How to make conductive plastic?

Researchers at the University of Chicago have found a way to make a material that is made like plastic, but conducts electricity like metal. Plastics are considered to be insulators, meaning their electrical conductivity is very low. Metals, on the other hand, conduct electricity very well, but are difficult to form, heavy, opaque and corrode. Already 50 years ago, scientists succeeded in creating conductors made of synthetic polymers, created by a doping process involving the introduction of foreign atoms into the material's crystal lattice. This produces materials with desirable properties: flexible and easy to work with. However, their properties are not stable: moisture and a rapid rise in temperature are a problem, causing a rearrangement of atoms and a consequent loss of electrical conductivity.

The structure of metals and polymer conductors is similar – atoms or molecules are arranged in strictly ordered, straight and interconnected rows. This allows electrons to flow easily through the material, much like cars move along a motorway. It was believed that a material must have straight, ordered rows in order to conduct electricity effectively.

The researchers experimented with materials that were discovered many years ago, but have not been used. Their structure is non-standard – shown above in the right of the image. Initially, the material was made of carbon and sulfur atoms – the scientists doped with nickel atoms and created connections between the individual strings. It turned out that a disordered structure was created, which in theory should not conduct electricity. Despite the lack of a solid foundation explaining how this polymer works, it all works. In addition, regardless of environmental conditions, the moisture and temperature.

The new material can be formed very easily. It does not need high temperatures for this, it behaves similar to plasticine. Conductive parts in computers, TVs or cell phones can be created by a simple industrial process. The material will change the way basically all electrical devices are built. What's more, it can take different forms, for example, scientists are testing porous finishes and both 2D and 3D structures. If everything goes according to plan, a revolution in device construction is in the pipeline.

LTE interference signal in DVB-T2 system.

The 700 MHz band is no longer used for terrestrial TV signals. This band has been made available to mobile network operators for 5G/LTE services. Therefore, the TV channels with the highest frequencies (channels above 40) are the most at risk of interference from LTE transmitters. The image on the TV screen may freeze, colored stripes and squares (picture frameup) may appear. How can such a diagnosis be confirmed? The best way is to hire an installer who is equipped with a professional meter.

Diagnosing the type and levels of signals often requires specialized methods. They will provide the information obtained as a basis for proper analysis and interpretation of making changes to the installation. One of the functionalities that provide such data is a spectrum analyzer (spectrogram), which examines and analyzes the frequency spectrum of all signals in the system in real time. A signal spectrum is the distribution of the intensity of desired signals and interfering signals (especially LTE) as a function of frequency.

Independent video outputs in Hikvision IP DVRs.

Hikvision IP DVRs, depending on the model, have the HDMI and VGA outputs where the image can be displayed independently or in parallel (the same image on both outputs). In the case of independent outputs, each of them can have different view and any camera connected to the DVR can be assigned to a particular window in a given view. Currently, all IP DVRs available in DIPOL's offer have at least two independent outputs, except DS-7600NI-K1 series, e.g. K22044 DS-7604NI-K1(B) and K22045 DS-7604NI-K1/4P(B). Some DVRs have additional BNC output in CVBS standard e.g. K22097 DS-7608NXI-I2/S where the image can also be set independently, but the maximum resolution of this output is limited to 704 x 576 p.

How to terminate fibre optic cables from flats in a multi-family building?

The most common way to terminate fiber optic cabling converging from apartments in a telecommunications room is to use RACK-mounted switches. These distribution frames are installed together with panels designed for copper cabling (twisted pair and coaxial cables).

If the investor wishes the fiber infrastructure to be separated from the copper cabling, it is possible to use a separate RACK cabinet or to use a metal distribution box. Such boxes allow, depending on the version, to terminate from 12 to 144 fibers, which results in 6 to 72 apartments. These boxes have space to accommodate an optical splitter in case the optical infrastructure is connected to a single operator. Otherwise, splitters should be installed in dedicated operator boxes.

For small buildings, where the number of apartments does not exceed 18, it is possible to use a well-thought-out, inexpensive, solidly constructed plastic box GXF6-15N5S, available under code L54036. 3 large-size input/output ports are provided: 2x dia. 25 mm, 1 x 43x13 mm. Additionally, there is space for the installation of up to 4 1/8 mini optical splitters.

Advanced motion detection configuration.

Hikvision IP cameras (except for some design devices) can define 8 independent motion detection zones, where each zone can have different sensitivity and detect objects of different sizes. This can avoid problems which may be caused by moving parts of the scene (e.g. leaves and branches moved by the wind), then the sensitivity in this zone should be reduced. Moreover, detection parameters can be different in each zone for day and night modes. In night mode, cameras often generate noise that can be recognized as motion by analytical algorithms. Therefore, it is recommended to reduce the sensitivity of motion detection in the night.

Video intercom system for an apartment block. A diagram of the Hikvision IP video intercom system for a 10-story (40 apartments) apartment block is shown below. Two identical sets of gate/door stations are installed at the gate and entrance to the block which include: main module with a camera (DS-KD8003-IME1/EU G73652), Mifare tag reader (DS-KD-M G73662), keyboard to control the first relay in the station (opening ) the wicket gate and calling individual tenants (DS-KD-KP G73668), and a display module indicating the door station status and allowing to choose s subscriber from the list (DS-KD-DIS G73670). The door station modules in the fence are enclosed in two surface-mounted frames (DS-KD-ACW2 G74354) with rain shields (DS-KABD8003-RS2 G74373)...>>>more