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No. 12/2015 (March 23, 2015)
Porto Smart City - the world's largest Wi-Fi network on the move.
The free of charge Wi-Fi network has been implemented in the second largest city in Portugal, Porto, in the form of over 600 routers installed in city buses and taxis. The "STCP Free WiFi" (STCP stands for Sociedade de Transportes Colectivos do Porto) is the world's largest Wi-Fi network on the move. The experimental service, provided by six months, ensures not only free Internet access for commuters but also gathers bus data that may help in the optimization of energy consumption, mitigation of environmental impact, and management of road and public transport. The technology of the network has been developed by Veniam – a spin-off company of the Universities of Porto and Aveiro, based in Porto and Aveiro in Portugal and in Mountain View in California. Porto is the first testing ground, but the company hopes to conduct such experiments in several American cities later this year.
It is well known that Wi-Fi technology has some drawbacks. Due to its limited range of several hundred meter, it would seem that the use of the technology in extensive urban infrastructure is meaningless. But the solution implemented in Porto contradicts this belief. The key to success is the use of suitable access points, also placed in vehicles of public transport, connecting to road side units or fiber access points scattered across the city and this way having access to the Internet. The process of switching between the devices is automatic and transparent to the user, just like it happens in the case of cellular networks.
NetRider units operate as roadside units and wireless routers in vehicles, depending on configuration
Both residents and the city government of Porto are satisfied with the pilot solution. Just in opposite to mobile phone companies - even the short tests of the mobile Wi-Fi network resulted in visible decrease in the amount of data transferred over cellular networks.
Signal-350 R86350 DVB-T modulators in series.
Thanks to the RF loop implemented in the devices, the signals from two or more such modulators can be physically combined by connecting them in series. Due to the fact that digital DVB-T signals are described by a number of parameters identifying each broadcast and channel, an additional device configuration has to be done to setup independent channels. The injection of two or more television signals from the Signal-450 DVB-T modulators requires to change the Program number parameter. The device configuration can be done by entering the menu and selecting Menu->Encoder->Program Info->Program number. The default value is "101". If the default settings were not changed, the televisions in the network would not be able to find and store some channels, even if they were distributed on different RF channels.
Signal-350 A/V-COFDM (DVB-T) R86350 encodes input analog audio-video signal into MPEG-2 stream that modulates RF signal in compliance with DVB-T standard (COFDM). The output signal can be distributed to hundreds of televisions connected to the antenna system.
In the diagram above, the video signals from two compact security cameras n-cam 670 M11284 are converted into two digital channels by two Signal-350 R86350 DVB-T modulators. The output signals, together with terrestrial DVB-T broadcasts received by the Tri Digit A2670 UHF antenna, are provided to a number of televisions via passive distribution network composed of R-3 R60103 splitter, Signal taps, and cable connections made of the Triset-113 E1015 cable.
The ATK-10 antenna has been further refined!
The the staff of the AGH University of Science and Technology in Krakow (from the Department of Electronics) has developed a new version of the ATK-10 A7015 antenna. The new ATK-10 is 10-element, outdoor directional antenna designed for receiving and transmitting cellular signals. The gain of the antenna is above 10 dBi, up to 12.8 dBi in the upper part of its 800 MHz to 980 MHz operating band. The features make it ideal for use with cellular Internet modems. The antenna is short-circuited for DC/LF current, which strongly reduces voltage surges caused by lightning strikes.
View of the new ATK 10 800-980 MHz A7015 antenna
Key features:
- Operating band: 800-980 MHz
- Gain: up to 12.8 dBi
- VSWR: max 1.8
- Short-circuited for DC/LF
- Number of elements: 10
The engineers have also tested the antenna and measured its characteristics. More details can be found on the catalog page.
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3D imaging of radiation pattern for 800 MHz | E-plane radiation pattern for 970 MHz |
FTTH - building cabling methods (part 3/3).
The previous issues of the Newsletter presented two ways of installing FTTH systems. The former one involved implementation of the entire system at the installation stage, regardless of the current needs, the latter method allowed for the expansion of the system along with the increasing demands of its users. The third FTTH technology, in a sense combining the two approaches described earlier, is the implementation of the cabling based on so-called "easy access cables". This method seems to be the most versatile and flexible way to bring fiber to apartments in multifamily buildings. | 1. Window cut marker on the sheath 2. Loose central tube with fibers 3. Aramid rod 4. LSZH sheath 5. 900 μm tight buffer fiber |
The structure of an easy access cable
Easy access cable is a fiber optic cable consisting of multiple fibers (e.g. 12, 24, 36 or 48) with 0.9 mm tight buffer coatings, located in LSZH tube. The fibers can be branched directly to individual subscribers without the need for splicing within the riser of the building. They are easily extracted from breaking windows in the gel-free tube. The breaking windows are protected by breakout units, the branch fibers are pulled out of the cable and conducted inside protective tubes to the subscribers' outlets. Any installation work connected with pulling out fibers can be carried out only after unwinding the cable reserve from the rack that is usually placed on the top floor of the building.
The installation of the cabling can be done in stages, first of the cable in the riser(s), then of the protective tubes, and finally - the pulling out of the fibers for selected apartments and splicing them with pigtails.
More information on easy access cable: "Fiber optics in homes in a few simple steps", as well as in the video below (so far with Polish soundtrack).
How to quickly add cameras to a Sunell NVR.
Sunell NVRs have simple and clear menu allowing for quick setup. The process of searching and adding network cameras should not cause a problem even for a novice installer. To add a camera to the DVR remotely via a web browser, the user should take the following steps:- search for cameras in the network and set the appropriate IP addresses, via dedicated software applications (Sunell - IPSearch , Signal - IPCSearcher, Hikvision - SADP)
- log in to the discovered cameras and change the passwords (factory logins and passwords: Sunell, Signal - login:admin, password:admin, Hikvision - login: admin, password:12345)
- log in to the Sunell NVR (login: admin, password: admin)
- select Quick Setup tab
- in the Authentication Accounts field create user/s with login/s and password/s identical with those in the cameras
- enter Camera Search tab and scan the network
- move to the next tab, add the appropriate cameras and accept all the settings
Sunell SN-NVR10/02E2/008NSE K2508 - adding IP cameras via Internet Explorer
If the Authentication Accounts field contains user/s with login/s and password/s identical with those of the cameras, then the added cameras will be automatically connected. Otherwise, the user should enter the authorization data for each camera.
HD-TVI systems - transmission of multiple signals over a single cable.
Hikvision TURBO HD cameras and DVRs represent a new category of CCTV equipment on the market. The transmission medium is the typical 75 Ω coaxial cable. Despite the analog form of the HD video signal, there is a possibility of transmitting additional data:- audio signal from the camera
- PTZ data
- camera OSD data
HD-TVI systems allow for sending additional signals over the video cable
The integration of so many different signals greatly simplifies the installation process - due to the reduction of the camera cabling to one transmission cable, the number of connections in the system is minimized. The configuration of HD-TVI systems is seamless and almost automatic. The installer does not need to set any addresses, transmission parameters etc. Optionally, using the menu of a HD-TVI DVR, the installer has access to the camera settings. So, the HD-TVI platform provides video quality and flexibility similar to IP systems, without the need for experience in network administration.
 | AC Transformer Pulsar AWT8172430 M18311 can supply various devices requiring 17 VAC, 24 VAC, or 30 VAC voltage, from 230 VAC power network, with power limit of 80 VA. The transformer is protected in the 230 VAC primary circuit by 0.63 A time-delay fuse (short-circuit protection) and thermal fuse (against overload/overheating, 130°C, not resettable). | |
 | Vibration Detector with Magnetic Contact SATEL VD-1 G3458 is designed for use in burglary and panic alarm systems. The detector employs two independent sensors, piezoelectric vibration sensor and magnetic contact, which makes it ideal for protecting a window or door against any intrusion attempts. The detector also has anti-tamper protection and NC relay output that can cooperate with any alarm control panel. Despite advanced electronics, the device features low current consumption. | |
 | UTP Patch Cable Cat.6 (1m, blue) J21111 with RJ45 connectors (8P8C modular plugs) is mainly used for connecting computers and other devices to Ethernet networks (LANs). | |
Worth reading
Remote power feeding of MV multiswitches in SMATV systems. Power supply over a coaxial cable is limited by the resistance of the cable. The voltage drop is directly proportional to the intensity of the current flowing through the cable. The total resistance (inner plus outer conductor) of the TRISET-113 E1015 cable is about 30 Ω/km. The H (18 V) lines of the SA-51 R70501 and SA-901 R70901 amplifiers can feed multiswitches with currents up to 2 A... more
Power supply through H lines
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