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

Sailing in space.

The use of sails in space may sound like a science fiction movie. However, this is no movie or fairy tale but a NASA technology demonstration. The independent agency of the U.S. federal government responsible for the civilian space program, aeronautical research and space exploration is testing new designs and material technologies for spacecraft propulsion systems intended for future low-cost missions. To that end, Rocket Lab's Electron rocket was launched in April 2024 from Māhia Launch Complex 1 in New Zealand. Just as a sailboat uses the wind to drift, solar sails use the pressure of sunlight for propulsion by positioning themselves at the right angle to the sun. In this way, elementary particles of light, called photons, can bounce off the reflective sail and propel the spacecraft, eliminating the need for conventional rocket fuel.

NASA's technology demonstration named the ACS3 (Advanced Composite Solar Sail System) mission uses a twelve-piece CubeSat module built to test a composite boom made of flexible polymer materials and carbon fiber, which is more rigid and lighter than previous designs. The key objective of the ACS3 mission is to test the new sail unfolding boom. The control system positions the solar sail at an angle to achieve the proper drift direction. Solar sails need very large, stable and lightweight booms that can be folded compactly. With a large sail, the spacecraft can be seen from Earth if the lighting conditions are right. When fully unfolded and properly oriented, the reflective material of the sail will be as bright as Sirius, the brightest star in the night sky.

How to find out on which wires power is sent to IP cameras?

In 10/100 BASE-T Ethernet networks, standardized power to cameras is usually implemented according to the 802.3af or 802.3at standard. The way the power will be sent is determined by the PoE switch, which can send power in two ways:

A powered device can provide both, or only one, of the power modes while remaining compliant with the standard. The powered device must therefore support both modes, but as it turns out in practice, not all end devices are fully compliant with the standard. This may be the reason for incompatibility with some power devices.
To check which wire pairs are used for power transmission, you can use the Alpsat AS33-IPCX M3214 meter, which has a function to identify (by measuring voltage) the wire pairs used for PoE (PSE application). Connect the equipment as shown in the diagram below:

Example results:

How to locate damage to a fiber optic cable?

FTTH cables installed in multi-family buildings are frequently exposed to damage. This is due to the fact that they are usually run together (in a corridor, a cable duct) with other cables (twisted-pair cable, coaxial cable), among which fiber optic cable is the most vulnerable to damage. The problem with flat fiber optic cable used in FTTH systems is that it is resistant to crushing and stretching, while if the minimum bending radius is exceeded, the risk of fracture of the FRP rods inside significantly increases, and this in turn leads to excessive bending and even fracture of the optical fibers.

Another reason is that these cables are often run in bundles of dozens or even more units. It is not difficult to damage some of them if this is the case. When pulling such bundles of cables, there is a risk that one or more of them will bend, which, with further pulling, will lead to its breakage.

The earlier the fault is detected the better. Replacing the cable at the laying stage will be much less problematic than replacing or repairing it when all the installation work is complete, and the damage will be made apparent by the measurement, which is necessary for the acceptance of the system.

Installers making FTTH systems, including those who are largely responsible only for laying cables in a building, should get an Ultimode OR-20 L5830 OTDR. This device can be used to generate a measurement report for the finished system, but can often come in handy at an earlier stage of the system to verify cable damage.

If damage to the cabling is suspected during installation, terminate one end of the cable with a pigtail, and then perform a basic reflectometry test with the Ultimode OR-20 using a launch fibre. The OTDR will show the length of the measured cable. If the end of the line occurs at a distance that is significantly different from the expected value (read from the cable markers), it will mean that the cable has been damaged (broken) at the point where the end of the measurement occurred.

Modern backbone network.

A 10 Gbps network is a computer network that allows data to be transmitted at speeds of up to 10 Gbps. Such high bandwidth is currently used in large enterprises, data centers and research laboratories. It allows large amounts of data to be exchanged in a short period of time which is especially important for applications such as cloud computing, high-quality video transmission or transferring large amounts of scientific data.

A backbone network is often used to transfer data between different departments within a company, between branches of a company or between different locations. Such capacity is needed to enable video conferencing, effective management, execution of sales and project processes, allowing the company to operate more efficiently.

In the case of a backbone network, each of the following cases uses fiber optics as the main transmission medium. An important aspect is that active devices support SFP (small form-factor pluggable) modules. Small Form-factor Pluggable (SFP) modules with a capacity of 10 Gbps. Such ports in the devices are labelled SFP+ (in many devices, SFP+ slots also allow connection of 1 Gbps SFP inserts).

The network below is built with a router and three different network switches. The first switch is TP-Link TL-SX3008F 8xSFP+ N30121 which is the most important device in the network. It is the one responsible for switching packets (the packet forwarding rate for this device is 119.04 Mp/s) with a total throughput of 160 Gbps. Two switches are connected to this device via optical ports: N30113 is responsible for connecting access points while N30112 connects computers and other network devices.

Uploading external applications to a Hikvision IP video door entry monitor.

The DS-KH9310-WTE1(B) G74009 and DS-KH9510-WTE1(B) G74011 video door entry monitors running on the Android operating system can install up to 5 external applications with the .apk extension. This makes it possible to operate several different systems with the video door entry monitor. The application to the monitor can be uploaded using iVMS-4200 software. To do this, after adding the monitor to the software, go to the tab: Access Control->Video Intercom->Application Software, select the monitor and use the Upload Application Software tab to indicate the file with .apk extension previously saved on the disk.

Channel amplifiers in SMATV systems.

The key issue in broadcasting the DVB-T2 digital terrestrial television programs is the reception of multiplexes with a large level differences. While in small systems (with 5-10 sockets) such a difference, although not recommended, is usually not an issue, in the larger ones, where the level difference at the input is increased by changing the attenuation of the cables along with frequency, it may cause signal loss in a part of the system. This effect can be eliminated by using channel amplifiers. The role of an amplifier is to selectively amplify one or, in case of receiving digital programs, several television channels. This means that the desired channel is amplified to the highest degree, and the others are attenuated.

DIPOL offers 2 channel amplifiers that are unrivaled in terms of quality and price: the PA320TP R82513 and PA420T R82516 TERRA models. An unquestionable advantage of the amplifiers is a circuit equipped with automatic gain control (AGC) function and ultra-selective SAW (Surface Acoustic Wave) filter for 20 channel tracks.

Export of recordings from Sunell DVR. Recordings from Sunell DVR can be ripped in several ways. The first is to use the local interface of the DVR – just connect a flash drive to the device. Another is to use a web browser or CMS application...>>>more