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

No. 5/2021 (Feb. 1, 2021)

Helicopter on Mars.

As early as in February 2021, the large Perseverance rover with the suspended Ingenuity helicopter will land on the Red Planet.
The Ingenuity helicopter is part of the Mars 2020 mission. Together with the rover, it is to verify whether there have ever been conditions for the development of life on Mars. The helicopter will verify whether NASA has the technology in place to fly directly above the surface of another planet. Ingenuity has been under construction since 2014. Interestingly, the helicopter will take off only when the rover moves at least 50 meters away from it. Perseverance will watch the flight with several cameras (the rover is equipped with 23 on-board cameras).

The NASA's helicopter is scheduled to arrive on the Red Planet on February 18, 2021.

Even a single helicopter flight will be a great success (the risk of the Ingenuity mission failure is very high). If the helicopter manages to take off from the surface more than once, it will undoubtedly be a huge success (the optimistic scenario assumes three flights). Due to low pressure, the first helicopter is a lightweight (1.8 kg) cube with a 14 cm long sides, and rotors 120 cm in diameter. The helicopter will fly 3-10 m above the surface and will be able to cover a distance of (as planned) even 300 meters horizontally.

Affordable router for home.

One of the most popular routers for home is the gigabit Archer C6 device supporting the 802.11n or 802.11ac standard at speeds up to 300 Mbps (2.4 GHz ) or 867 Mbps (5 GHz), which makes it possible to create high-speed wired and wireless network connections. It is designed for small enterprise and home use. It uses the MU-MIMO technology ensuring unprecedented transmission efficiency, making it possible to transmit HD video, VoIP communication and online games. The stylish housing of the device has a button that activates the Wi-Fi Protected Setup (WPS) function, activating WPA2 encrypted connections to protect the network from external threats.

Key features:

Support for 802.11ac standard - the latest generation of Wi-Fi networks,
Simultaneous connections up to 300 Mbps at 2.4 GHz and up to 867 Mbps at 5 GHz,
Four integrated external antennas provide stable signal and superior wireless coverage,
Gigabit Ethernet ports ensure high transmission speed in wired network.

Wireless Dual-band Gigabit Router: TP-Link Archer C6 AC1200 (4x10/100/1000 Mbps)

Gigabit Router TP-Link C6 Archer MU-MIMO AC1200 4x10/100/1000 Mbps N3255

Hikvision video intercom system in the 2-Wire standard.

There is often a need to replace the existing intercom (video) system with a newer one, offering greater functionality and quality. Such an upgrade may require replacement of the cabling, e.g. with twisted pair cables for IP systems. The Hikvision video intercom operating in 2-Wire standard is of help. It has the same functionality as the 2nd generation Hikvision IP video intercom. Building a compact system involves connecting of monitors (e.g. G74018 DS-KH6320-WTE2) and the main door station module (G73644 DS-KD8003-IME2) to the G74823 DS-KAD706 distributor via a 2-wire bus. The 2-Wire bus allows for both, powering the devices and establishing communication. After connecting the distributor to the LAN network, each device (monitor, door station) is visible in the network under a separate IP address. The iVMS-4200(v3) application is used for configuration. In addition to the basic functionality, i.e. video calls, the system controls opening the wicket and controlling the entrance gate, also can also be controlled with the Hik-Connect application from a smartphone. It can redirect a call to the phone while the tenant is absent and remotely open the wicket or gate.

Sample diagram of a system using the 2-Wire Hikvision system

Double verification of access rights to recordings.

A monitoring system operator can usually access a DVR througuh an account with limited access rights. It usually allows for a preview of current images from cameras, while viewing archives requires logging in to an account with higher privileges.
Hikvision has introduced the function of double verification of access for a temporary extension of access rights. If the operator wants to access the recordings, additional credentials (specially created for this purpose) are required. He remains logged in to his account, but gains temporary access to view the recordings.
The double verification function works for both local and remote access (via a browser and iVMS-4200). It supports viewing and archiving recordings.

View of the double verification settings window in Hikvision CCTV systems

Optical and copper TV/SAT system in a hotel.

The designer was given three main objectives to meet. First of all, the system has to cover 5 buildings of a large complex. It is supposed to distribute DVB-T/T2 signal from a local transmitter, and 15 satellite programs in the form of digital DVB-T/T2 signal. In order to ensure the best possible terrestrial TV signal and to equalize the signal levels at the input of the system, the contractor decided to use a digitally programmed four-channel TERRA at440 R82511 amplifier. In addition to that, to add the VHF and FM band signal, the multiband FM/VHF/UHF ma400 R82520 amplifier was used.

Diagram of the optical and copper system for 5 hotel facilities with DVB-T/T2 signal distribution (4 digital terrestrial TV multiplexes and 8 multiplexes from the tdx-480 R81621 transmodulator). Part of the source signal was allocated to the local subnet (the building with the service room). Single-mode optical fibers were connected to the remaining buildings.

The satellite channels are received and converted into DVB-T standard by the tdx-480 R81621 transmodulator. The set of the panels used allows for the reception and conversion of 16 satellite Full HD channels from eight transponders.

The DVB-T/T2 signal prepared for distribution is transmitted to other buildings via single-mode optical fiber. The mo418 4D31 R82522 optical transmitter with a laser power of 6 dBm was used to for that purpose. Moreover, the so414 R82527 optical splitter is mounted on the same DIN R82538 rail to divide the signal into four optical paths. The transmitter is powered by the DR-60-12 12V/4.5A R82532 power supply. The inverse conversion of the signal from the optical medium to copper wire is performed in hotel buildings by TERRA OD-005P R81760 optical nodes. The maximum signal level at the output of the node is 107 dBµV which allows the TV signal to be distributed to several dozen R62120 sockets without the need of additional amplifiers. In such a configuration of optical fiber devices, the DVB-T/T2 signal can be transmitted to a distance of up to 12 km.

Fiber optic TV systems – optical signal level vs. RF signal quality.

Optical fiber is increasingly popular in SMATV systems. It is a solution of choice for safe installation (no overvoltages) and as a cure to the transmission limitations of copper cables. The TRIAX TOU 232 A9880 set and TVQ 06 QUATRO A9882 receivers are often used when the main signal bus is based on optical fibers, while the access part of the system (subscribers) is made of standard copper cabling connected to multiswitches.

The installation itself, using this type of equipment, is not difficult. As a rule, ready-made fiber optic patch cables are used. For terminations made individually, single- or double-fiber cables are processed. The workload to make connections in boxes or distribution frames is therefore not significant. Problems, if any, relate to substantial loss of signal quality after copper-optical-copper conversion. There may be several reasons for that:

low quality of the input signal provided to the optical transmitter (improper antenna, insufficient signal parameters) - the conversion of the medium always slightly deteriorates the quality of the digital signal (more on this below), so it is necessary to ensure very good or at fairly good parameters of the input signal to avoid any problems at the input of the system;
too high level of the input signal - very often the optical transmitter is preceded by an RF amplifier built into the antenna or a mast amplifier, in most cases it will result in overdriving the optical transmitter, whose maximum input level for the DVB-T signal is 97 dBuV, and the recommended level is only 70 dBuV. A normal professional DVB-T antenna equipped only with a balun can provide 70 dBuV level at distances up to 15 km from a typical DVB-T transmitter;
too high level of the optical signal at the input of the A9882 receiver, which also results in overloading the optical input and deterioration of the output RF signals that carry an unacceptable numbers of errors.

The last reason mentioned above is the highest percentage of errors made by installers. Often, due to the lack of measuring tools, they are not able to verify the actual signal level at the receiver. In theory, such meters are not necessary, as all the information needed to determine the power budget for a given connection is included in data sheets of the devices and passive components. However, in installation practice, one may face a number of surprises (excessive cable or pigtail bend, dirty connector), and the actual parameters of such elements as attenuators or splitters may differ from the declared specifications. For that reason, it is recommended to use optical power meters such as Grandway L5822 or Signal R10837 (multifunction device with optical power meter) even with simple point-to-point connections.

The example below shows how too high level of optical signal affects the quality of the signal on the receiving side. The measurements were also performed to analyze the overall deterioration of the signal quality caused by the signal conversion (copper - optical fiber - copper) for normal signal levels. The measurements were made for a DVB-T channel at 506 MHz.

The signal level measured directly at the DVB-T antenna is 65.4 dBuV (the recommended range is 67...97 dBuV). So, it is a little less than the minimum given by the manufacturer of the A9880 set, but taking into account very good signal quality parameters (MER 35.3 dB and BER 3x10^-5), no additional amplifier has been used.

The next step is to verify performance of the optical transmitter. Using the GRANDWAY FHP2B04 L5822 meter and the L3233 patch cable, the signal strength at the transmitter output was measured. The meter read 7.11 dBm for a wavelength 1310 nm, which is in line with the manufacturer's specifications. Then, the transmitter was connected to the Quatro A9882 receiver using a previously prepared fiber optic cable. It is the most common installation routine based on this set (no splitters, no attenuators). Signal with a power of approx. 7 dBm was then supplied to the receiver. This is the most common mistake the installers make. The permissible power range is -15 ... 0 dBm. Measurement of the DVB-T signal at the output of the receiver showed the signal strength of 80.9 dBV and the AGC system in the receiver worked, but its quality was virtually immeasurable. The MER and BER indications were very low or immeasurable. Of course, such a signal is not suitable for further distribution in the system.

New products offered by DIPOL

		Hikvision DS-KV6113-WPE1 IP Villa 2 door/gate station G73624. Elegant design and small dimensions allow you to mount the station on a narrow post. Built-in color camera with a resolution of 2 MP with wide viewing angles (129° (H)/75° (V)) and an IR illuminator with the range of 3 m, , ensures proper area observation round the clock. Built-in Mifare (13,56 MHz)+++ transponder reader allows for door opening with cards or key rings.

		TP-Link TL-SG2210MP PoE switch Smart N29965 is an advanced device for network traffic management. Available management options include command-line interface (CLI) and management via web browser. Gigabit managed switches ensure very high stability and performance. Reliable operation of the network is also supported by spanning tree protocol, QoS and robust transmission security features.

		The HDMI to twisted pair converter Signal 4K60 ipcolor H3644 enables the transmission of the HDMI signal over long distances using the twisted pair cable category 6 or higher. The device transmits a lossless image supporting HDMI 2.0, HDR (18 Gbps band), DTS. Additionally, the converter has an integrated remote control extender.

Worth reading

Apartment building monitoring using ColorVu cameras. The diagram below shows the monitoring of an apartment building based on an NVR and Hikvision IP cameras, belonging to the EasyIP4.0 ColorVu series. The key feature of this series is scene monitoring in color mode around the clock, so the color related information is preserved regardless of the prevailing lighting conditions. The outside area around the building is monitored by eight DS-2CD2047G1-L K03114 compact cameras with 4 MP resolution and 2.8 mm lens with 102° viewing angle. Four ceiling cameras DS-2CD2347G1-L K00311 with a resolution of 4 MP were used inside the building... www.dipolnet.com/inf_dipo_2021_04.htm#02***