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

Wireless power transmission.

In April 2022, the U.S. Naval Research Laboratory conducted a test of a wireless power transmission system by transmitting 1.6 kW of power over a distance of 1 kilometer. This result was achieved using microwave radiation. The idea of transmitting energy over long distances without wires has been around for over a century. Electricity is converted into microwaves (10 GHz) which are then focused into a narrow beam.

The Safe and Continuous Power Beaming – Microwave (SCOPE-M) project has been tested in two locations. The first is the U.S. Army Research Field at Blossom Point, Maryland, and the second is the Massachusetts Institute of Technology (MIT).

SCOPE-M is built with tens of thousands of X-band (8-12.5 GHz) antennas. Each of these antennas is connected to a small rectifying diode that converts the microwaves it receives into electricity. In Maryland, the team transmitted 1.6 kW of power over just over 1 km. Importantly, the radiation is safe for humans and animals.

The SCOPE-M solution may one day be used to transmit energy from large orbital solar power plants to deliver electricity to earth. However, a more down-to-earth application that the U.S. Department of Defense is interested in is sending energy directly to field bases where soldiers are stationed eliminating the need for troublesome fuel deliveries.

TRI-SHIELD RG-6 A+ coaxial cable with 1.13 mm conductor.

Television systems are multi-cable installations, i.e. the ones where several dozen cables are installed one next to another. Since the cabling covers the whole building, the length of the cables can reach up to 100 meters. In such situations, it is very important to use coaxial cables with high screening class A or A+ and copper conductor of at least 1 mm in diameter. Effective screening eliminates the probability of cable crosstalk. It consists in induction of unwanted signals in neighboring cables. It is manifested on the screen by image interference: pixelosis and freezing of scenes as it occurs in the case of a weak or low quality signal. Quality coaxial cable should ensure low insertion loss and high screening efficiency. Taking the risk of installing cable with untested parameters can result in having to replace the entire cabling shortly after installation and result in missing the delivery date of the project.

DIPOL offers a new, competitively priced Tri-Shield coaxial cable DIPOLNET RG-6 E1215_500 dedicated both, for individual antennas and SMATV systems.

Why is the information about DNS servers important for network devices?

To change public (external) IP addresses from numeric to a domain format, the DNS (Domain Name System) is used. Hence, there is no need to remember the addresses e.g. in the 62.121.130.38 format, but just a much more friendly www.dipolnet.com instead.

Translation of numeric to domain is performed by an appropriate DNS server to which the device sends a translate request. After receiving a response with a numeric address, the host establishes connection with the appropriate server.

Often, when configuring network devices (manually assigning an IP address), the DNS server address is forgotten. Most network devices such as managed switches or access points will work "almost" normally. The problem that may arise in this case is the lack of synchronization. This is due to the fact that the NTP server address is usually given in domain form. The lack of time synchronization results in incorrect time in the logs.

If the DNS server address is not provided in devices such as NVRs, the problems will be much more noticeable. As a rule, they will manifest themselves on the first attempt to connect to the DVR from an external network. This connection will require proper translation of server addresses associated with the implementation of services in the so-called "cloud". Without knowledge of the DNS server, this will not be possible, which in turn will make the connection with the DVR impossible.

How to repair broken optical fiber?

DAC (Direct Access Cables) make a popular group of fiber optic cables that can be laid directly in the ground, without the need for additional protective conduits. These cables are used in practically every kind of fiber optic systems, from local monitoring systems to operator applications, most often as the "last mile" section, i.e. at the direct customer connection.

DAC cables can be damaged (ruptured) due to earth works carried out in the area or spontaneous earth pressure (landslides, freezing of the ground) that exceeds strength parameters of the cable.

It is best to replace the damaged cable. If it is not possible ends of the broken cable can be joined by splicing a piece of new cable in between. Of course, two couplers have to be used to secure the connection point. These couplers should be as tight as possible. A good practice is to use more seals in addition to those offered by default.

The picture below shows an example using a repair couplerL56040 to connect two dual-fiber DAC cables. The coupler has a rubber seal and a bolted cover to ensure a high tightness. It is advisable to protect the rubber covers on the cable entries, especially when using cables with diameters below 5 mm.

Update of expansion modules connected to Hikvision IP/2-Wire video door station.

Expansion modules connected to DS-KD8003-IME1 G73205 or DS-KD8003-IME2 G73304 modular door stations can be upgraded from the main door station using the iVMS-4200 application. After adding the main door station with properly connected modules to the iVMS-4200 client application, go to the main door station settings and then: System -> Maintenance-> Upgrade. Select the Display module tab or Sub modules and provide the link to the previously downloaded firmware and confirming with Upgrade. The upgrade process begins.

How to power an IP device without PoE using twisted-pair cable? When an IP device, e.g. a camera, that does not support PoE 802.3af/at standard needs to be installed in a place where only twisted-pair cable is laid, there is a problem with its power supply...>>>more