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

The triumph of intelligent multipoint-to-multipoint wireless mesh architecture.

The world's longest wireless network based on mesh technology has been deployed in Thailand. The network, built by an American company Firetide, covers a distance of 372 km. It has been conceived as a kind of a gift from Thailand’s Royal Irrigation Department to the 84 year old King of Thailand, Bhumibol Adulyadej. The network is to provide images of the floodplains of the river Chao Phraya. Due to his age, the king is no longer able to oversee the monitored areas in person. The implementation of such a gift turned out to be technically challenging.

The total cost of the world's longest wireless mesh network is about 2 million USD. However, this sum of money is not large considering the fact that during the last monsoon season the network gave the chance to save hundreds of people from flooding. The Thai network belongs to the group of early warning systems for floods.

The entire network has been built based on mesh technology. The main advantages of this type of network architecture include auto-configuration and full redundancy in the case of a node/link failure. The latter feature is guaranteed by an automatic change of the route of data packets, which is particularly important in so large and responsible systems.
The main components of the network are 64 Firetide HotPort 7020 wireless mesh nodes and 27 Panasonic PTZ WV-SW395E cameras. The distances between nodes range from 20 to 45 km. The total throughput of the network is as much as 240 Mbps, with node-to-node latency below 1 ms.

High throughput is achieved by the use of Firetide HotPort 7020 mesh nodes, compliant with 802.11n standard and implementing MIMO multi-antenna technology, with 40 MHz wide channels. The routing of the frames is based on proprietary AutoMesh mechanism, based on the 802.11s standard for wireless mesh networks approved in the last year. [source: firetide.com]

Last year's approval of the 802.11s standard can accelerate the popularization of wireless mesh technology. Until now, mesh networks were mostly implemented as experimental projects, not having much in common with the commercial market. Today, in addition to the large-scale undertaking in Thailand, some more "ordinary" projects are carried out, such as the city video surveillance system in Altanta, with 110 cameras. Time will tell whether mesh technology will be more popular on European markets.

Speakers on the wall? - No problem.

For anyone wishing to use the full benefits of a modern home theater, a good sound system is just as important as a high-end television or projector. The placement of the speakers in the room is a crucial issue.

An excellent organization of the sound system is enabled by Signal speaker mounts/brackets. The SB-32-2 E93810 bracket can hold two speakers on the both sides of the monitor/television. Signal E93805 SB-35 mounts are used to place on walls heavy, powerful speakers. The load capacity of the mounts is 30 kg. The SB-03 E93801 mounts with full freedom of movement enable users to position the speakers in the desired orientation.

Signal mounts include wall, ceiling, and desk hardware, as well as projector mounts.

Fiber-optic SMATV systems.

SMATV systems based on optical technology are becoming an increasingly popular method of distributing television signals in apartment buildings and housing developments. Thanks to fiber-optic solutions, the signals can be easily fed to a number of buildings, even when they are located at considerable distances from one another.

The diagram below presents the idea of a fiber-optic SMATV system.

The idea of a fiber-optic SMATV system distributing satellite and DVB-T signals

Satellite channels (received by the FibSZ-LNBF downconverter of the A9880 kit) and terrestrial DVB-T plus DAB signals are fed through coaxial cables to the FibSZ-ODU32 converter/optical transmitter (the second basic unit of the A9880 kit). Then the output composite optical signal is distributed via a single-mode optical fiber to a cascade of two-way optical splitters A98892. Each of the four paths can feed the optical signal to different locations equipped with optical receivers/converters that convert it into electrical form (RF signal). In the case of several R694100 outlets, the RF signal can be directly provided to them from the A9883 optical receiver, or when the number of outlets should be higher, the A9882 FibSZ-QUATRO converters can form the nodes of subnetworks based on multiswitches. Such subnetworks may contain a single multiswitch or a multiswitch system for a larger building (with taps and amplifiers, for distributing signals up to several hundred outlets).

How to choose the right lens for a security camera?

Camera lenses are important components of CCTV systems. A wrong choice can result in poor image quality, regardless of the quality of the other equipment used in a system. A common mistake is, for example, the application of a lens intended for 1-megapixel cameras with a 2-megapixel device.

Each lens has a limited optical resolution, usually expressed in numbers of line pairs per mm (lp/mm) or directly in pixels. For analog cameras with 1/3" image sensors, the sufficient resolution is 80 lp/mm. The value is calculated by dividing the resolution of the sensor used in such a camera (typically 576 lines) by the actual dimension of the image expressed in mm (3.6 mm in the case of 1/3'' sensor) and dividing the result by 2 (to get the number of line pairs per one millimeter).

For an IP camera with 1/3" 2-megapixel sensor the right lens should have a minimum resolution of 150 lp/mm (1080/3.6/2 = 150 lp/mm), which is nearly twice as high compared with conventional lenses for analog cameras.
In the case of the smaller 1/4" image sensors, also used in many cameras, the pixels are packed tighter. It usually results in lower sensitivity and greater demands for the quality of the optics. For example, an analog camera with 1/4" sensor will require to use a lens with a resolution of 576/2.4/2 = 120 lp/mm, and a 2-megapixel IP camera - with a resolution of 1080/2.4/2 = 216 lp/mm.

ClearHD M2272 lens for cameras with resolutions up to 2 MP

How to inject images from IP cameras into antenna systems?

The injection of video signals from analog CCTV cameras to antenna distribution systems requires only application of RF modulators. IP cameras provide streams of data instead, and when the cameras don't have additional analog outputs, the images cannot be displayed on multiple TVs using methods typical for analog systems.

The problem can be solved by the application of the multifunctional HDMI-COFDM (DVB-T) modulator Signal-751 R86751, connected to the HDMI output of K4416 network video recorder. The HDMI output can provide Full HD video from the IP cameras (e.g. K1680), which modulates the output RF signal of the modulator in the form of a DVB-T multiplex.

Injection of images from IP cameras into antenna system

The Signal K4416 network video recorder can provide the images from the cameras in 2x2 screen division mode, or sequentially, in full-screen mode. In the latter case the dwell time is fully adjustable.

Gigabit VPN router from TP-LINK.

The TL-R600VPN SafeStream™ N3385 gigabit broadband VPN router provides Gigabit Ethernet connections both on WAN and LAN ports. The device supports multiple Virtual Private Networks (VPN) protocols, ensuring high security and excellent performance. This functionality is especially useful in office networks, allowing for remote access to resources while maintaining maximum security. In addition, the security policies used in the TL-R600VPN router, such as SPI firewall, DoS attack protection, and IP-MAC binding help protect the network against the most common attacks. TL-R600VPN is the ideal device for small offices that need cost-effective and reliable VPN solutions.

The VPN tunnels supported by the TL-R600VPN router provide secure links between client terminals through a public network (usually the Internet), with the use of IPsec and PPTP protocols. The router can also handle IPsec/PPTP/L2TP "pass-through" traffic. The hardware-based VPN engine can handle up to 20 IPsec LAN-to-LAN and 16 PPTP VPN connections.

The VPN TP-LINK TL-R600VPN SafeStream N3385 router

Fiber cable management. Splice enclosures or panels provide locations to store all splices/connections safely and efficiently. Any installer of fiber optic cabling has to have the necessary skills to connect/terminate/arrange the cabling in network nodes, interconnection and end points. One of the ways to terminate optical fibers is to connect them with pigtails, adapters and patch cords... more

Ultimode P-6 L5506 fiber optic box with trays holding
Ultimode Fast-MS1 L5550 mechanical splices

DVB-T television and the Internet via one UTP cable. Low-voltage systems in office buildings often do not include TV antenna cables, but are usually fitted with structural cabling based on UTP cables. When some users want to connect televisions to watch DVB-T broadcasts, the lack of an RF distribution system may be a major obstacle (in many locations TV signals cannot be properly received using indoor antennas)... more

Transmission of DVB-T and Ethernet signals over a single UTP cable with the use of R94200 baluns

Gigabit fiber link. Such links solve communication problems in medium-sized and large companies. They can be built with the use of media converters or switches with SFP modules.
A stable fiber optic connection with Gigabit throughput can be based on ULTIMODE M-203G L11025 media converter (placed on the service provider side) and Web Smart Switch TP-Link N29949 equipped with ULTIMODE SFP-203G L1415 SFP transceiver. This set of devices can transmit data through a pair of single mode fibers over distance up to 20 km. The company's network uses TP-Link switches.