TV-SAT, CCTV, WLAN Dipol Weekly Review

Laser data transmission unaffected by atmospheric turbulence.

Researchers from the University of the Witwatersrand and the University of Bordeaux have unveiled a technology that could revolutionise the way free-space optical links are built. They have demonstrated that information carried by a laser beam can withstand severe atmospheric turbulence without the need for any optical correction. This approach is completely different from all previous FSO systems, which must measure distortions, compensate for them using adaptive optics, and perform complex calculations to recover the data. Here, the information remains intact, even when the light beam itself is severely distorted. The key to this effect lies in the way the data is encoded. Instead of using colour, intensity or the polarisation of light – parameters that are highly susceptible to interference – the researchers encoded the information in the beam’s topological structure. Topology describes characteristics that remain unchanged despite deformation. Just as a mug and a doughnut each have a single hole, even though they look completely different, so too can certain properties of light remain unchanged, even when the beam is ‘ripped apart’ by the atmosphere. It is precisely this property that was utilised for data transmission. In an experiment conducted on the Wits campus in Johannesburg, laser beams were transmitted over a distance of several hundred metres under entirely natural conditions. The atmosphere distorted the light very significantly (the shape of the beam at the receiver was completely different from that at the transmitter), but the information encoded in its topology remained fully intact. This is the first demonstration of such resilience in a real-world environment, outside the laboratory.

Optical skyrmions and stably rotating light field structures, which retain their properties even under severe distortions, were used to encode the data. A skyrmion can be thought of as an ordered vortex in a light field, the configuration of which remains unchanged no matter how much external conditions try to distort it. It is precisely this stability that makes skyrmions an ideal carrier of information in challenging transmission conditions. This technology has the potential to significantly simplify future optical communication systems. The absence of the need for beam correction means less electronics, less adaptive optics, lower costs and greater reliability. Applications include satellite communications, links to spacecraft, transmission in adverse atmospheric conditions, and improved connectivity in underdeveloped regions. Applications in quantum communication, where maintaining the integrity of information is crucial, are also particularly promising. Optical skyrmions are currently the subject of intensive research in photonics, as they could become a new, exceptionally robust data carrier. Thanks to their topological properties, they are unaffected by distortions caused by the atmosphere, so the information remains intact even when the light beam itself undergoes severe distortions. This approach is changing the way we think about free-space optical transmission, as rather than fighting turbulence, it allows us to bypass it entirely. Whether the technology will find practical applications remains to be seen in subsequent stages of research, but all the signs suggest that we are witnessing the birth of a solution that could become one of the greatest breakthroughs in optical communication since the advent of fibre optics.

Why is it important to calibrate a fibre-optic splicer?

Calibration of a fibre optic fusion splicer involves adjusting the power and temperature of the electric arc generated to suit the current environmental conditions. A correctly adjusted arc enables the production of sound splices – both in terms of attenuation and strength. Calibration should therefore always be carried out before the actual welding begins – at the start of work or when conditions change drastically (e.g. a sudden drop in temperature resulting from finishing welding indoors and continuing work outdoors).

The most expensive models of fusion splicers are equipped with pressure and temperature sensors that allow for an automatic calibration in real time. Most popular devices, however, require manual calibration, which will take several minutes. Skipping calibration will not always result in bad splices. However, there is a risk that some, even those indicating low attenuation, will be very weak and unstable mechanically (e.g. if the splicing temperature is too low, they may sometimes crack after an hour).

Signal Fire fibre optic fusion splicers: AI-5 Pro L5872, AI-9 L5875 and AI-12 L5876 are based on a popular calibration method – the fibres, placed in the splicing chamber, are subjected to successive electric arcs. The fibres melt, and the splicer’s software measures and analyses the distance by which the fibre ends retreat. The appropriate electrical arc parameters are determined on the basis of this measurement.

The Signal Fire calibration process is carried out by selecting the ‘Arc Calibration’ option in the management application (AI-5 Pro) or in the on-screen menu (AI-9, AI-12). Once the fibres have been inserted into the fusion chamber and the lid has been closed, the calibration process starts automatically. Once it is complete, the fusion splicer switches to Normal mode, i.e. fibre splicing.

During the autumn and winter months, installers should pay particular attention to preparing their equipment properly before starting work. A welder that has spent the night in a car parked outside, when brought into a room with room temperature, is unsuitable for immediate work: fogged camera lenses can affect erroneous verification of fibre position and autofocus problems. To avoid this problem, the splicer should not be allowed to cool down.

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Model	Signal Fire AI-5 Pro	Signal Fire AI-9	Signal Fire AI-12
Code	L5872	L5875	L5876
Number of motors	6	6	6
Magnification	x300	x300	x320
Min. splicing time	8	5	5
Min. splicer cover heating time	18	15	15
Mobile app	Yes	Yes	Yes
Number of splices per full charge	160	240	260
Built-in OPM and VFL	No	Yes	Yes
Presets for splicing different fibre standards	No	No	No
Touchscreen	No	Yes	Yes
Spare set of electrodes	No	Yes	Yes
Self-closing furnace	No	Yes	Yes
Holder for heated splice covers	No	Yes	Yes
Guillotine with automatic blade rotation	No	No	No
Storage and transport	Bag	Case / Case	Case / Box
USB port	No	No	No
LED	Yes	No	No
Smart Lock features (app)	Yes	Yes	Yes
Warranty period	3 years	4 years	4 years

Ballast masts for low-voltage installations.

Ballast masts are structures designed for the installation of antennas, lighting, signalling or other equipment on roofs and other flat surfaces, without the need to interfere with the structure of the ground. Their stability is ensured by appropriately selected ballast (usually concrete weight plates), which prevents the mast from toppling under the influence of wind or vibrations. Ballast masts are widely used in temporary and permanent installations, particularly where permanent anchoring of the mast is not possible or where the integrity of the roofing is required. A variety of mast heights are available as required and the ballast weight is selected to meet the safety requirements of the wind zone. The size of the ballast frames / ballast has been selected so that they can be lifted onto the roof even through a small roof hatch.

DIPOL offers 5 models of ATLAS brand ballast masts, designed for various installation applications. Each is characterised by different design features, such as height, load capacity, number of sections or installation method, allowing the solution to be tailored precisely to the individual user's needs.

Features and benefits of ballast masts:

Which SD cards are suitable for use in CCTV systems?

SD cards are a key component of CCTV systems and are used in both IP cameras and mobile recorders. Choosing the right card is crucial for stable recording, high-quality footage and reliable operation. In the context of CCTV, the card’s technical specifications – such as capacity, speed class and durability – are particularly important.

SD cards are divided into SDHC and SDXC. SDHC includes smaller capacities and is compatible with older devices. These cards use the FAT32 file system and have a maximum capacity of 32 GB.
SDXC offers a larger capacity and is designed for modern camcorders and long-term high-definition video recording. The file system is exFAT, allowing for large video files and long-term recording sessions, and the capacity of these cards can range from 64 GB to 2 TB.

Data write speed The standard ‘C’ class (e.g. Class 10) and the newer ‘U’ class (e.g. U1 or U3) specify the minimum guaranteed write speed in megabytes per second. For example, U3 indicates a guaranteed 30 MB/s. There are also classifications with the letter A (A1, A2), which indicate how efficiently the card supports applications on a mobile phone.

For cameras and recorders, the most important rating is the ‘V’ symbol (standing for Video Speed Class), e.g. V10, V30 or V90. The number following the letter V indicates the minimum continuous write speed in megabytes per second. This ensures that such a card correctly supports the writing of large files at a high bitrate.

Selection and installation of an antenna for LTE MIMO.

When selecting an antenna, it is necessary to obtain information on the location of the nearest transmitters that emit a signal in a specific standard. Such information is provided by customer service offices of the respective operators. It is also worth to verify the frequency of emission assigned to a particular service.

If the base station supports several bands, e.g. LTE800, LTE180, LTE2100, and the router has an aggregation function, a broadband antenna should be used. The antenna should be chosen according to the distance between the reception site and the operator's transmitter.

The video below shows a solution to a “slow” Internet problem caused by a weak LTE network signal. Replacing the factory antennas in the router with professional, external ones significantly improves the level of the received LTE signal, so that data transmission speeds up. The video uses a TP-Link Archer MR200 N3263 LTE router with a set of ATK-LOG LTE MIMO A7054 antennas connected to it.

Which Signal Fire fusion splicer should you choose? Choosing the right fibre-optic splicer is one of the key decisions for telecoms companies, network installers and fibre-optic infrastructure maintenance engineers. There are many models available on the market, which differ not only in price but also in splicing precision, operating speed, durability and additional features such as automatic calibration or advanced diagnostics. The choice of the right device should depend on the specific nature of the work to be carried out, the frequency of use and the expected quality of the connections. In this article, we’ll look at the most important parameters to consider before purchasing a fibre optic splicer...>>>more