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DIPOL Týdenní přehled - TV a SAT TV, CCTV, WLAN
No. 07/2015 (Feb. 16, 2015)
From London to New York without an amplifier. Researches from the University College London have found a way to increase the distance over which data can be transmitted via a fiber optic cable without the use of amplifiers and repeaters.
One of the phenomena that limit the useful transmission distance is the Kerr effect, discovered in 1875 by John Kerr, a Scottish physicist. In the Kerr effect, a change in refractive index is proportional to the square of the electric field. Light from lasers can cause the effect by its own electric field, which is called the AC Kerr effect. Additionally, with the use of different frequencies of light creating the data signals, they can interact with each other and distort. To prevent errors, the losses and distortions of the optical signals transmitted over long optical fibers have to be compensated by the use of active devices such as amplifiers or repeaters.
Map showing the distribution of submarine fiber-optic cables
The active devices are the most vulnerable components of the submarine optical links, especially in the case of intercontinental transmission, with cables laid on the ocean floor. By using a new type of receiver and advanced signal processing algorithms developed by the researchers from London, it will be possible to carry out intercontinental transmission without the signal regeneration points.
By eliminating the interaction between optical channels, the maximum distance of error-free transmission can be almost doubled, from 3190 km to 5890 km. This is the largest increase that has ever been recorded in the architecture of these systems.
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.
The supply voltage of MSV multiswitches can vary between 12-18 V, and each of them consumes 90-60 mA. So, one amplifier can power up to 20-30 multiswitches.
Steel Satellite Dish: TRIAX 115 TD (dark gray)Universal QUATRO LNB: Inverto Red Extended 0.3dBAmplifier for 5-input multiswitches: Terra SA 51 SAT/TV TAP: Terra SS-520Multiswitch Terra MV-508 (5-in, 8-out, IF gain adjustment)UHF TV Antenna: DIPOL 44/21-60 Tri Digit
Power supply through H lines
The calculation using Ohm's law shows that at the maximum load of the amplifier (2 A) and with the resistance of the cable of 0.032 ohm/m, there is ca. 6 V voltage drop over a 100 m length of the cable. Incidentally, it is the maximum distance at which one can provide power supply under these conditions (18 V - 6 V = 12 V, the lower voltage limit for the multiswitches).
In practice, the number of multiswitches is usually much lower than that limited by the current capacity of the amplifier. For example, with five MSV-516 R70716 multiswitches, the current consumption from the amplifier is about 0.45 A. For this value the voltage drop over the E1015 cable is around 1.44 V per 100 m, which translates to the maximum distance of about 400 m (taking into account voltage drops in passive components - SS taps - below 0.1 V).
Access point with separate antenna or an integrated device? Until recently, a popular way of the access to the Internet was the use of an external WLAN/Wi-Fi antenna connected via suitable coaxial cable to the router / access point placed inside the building. However, such solutions are effective when the distance between the access point and the antenna does not exceed ca 10 meters. The attenuation of longer cable runs is usually the reason for using other solutions.
Now, the increasingly popular solutions are based on the concept of integrating the antenna and active device (access point). The connection to the rest of the network placed inside the building is made with the use of typical twisted-pair cable (UTP/FTP). This kind of transmission medium does not impose such severe restrictions on the length of the cable from the roof to the next active device. This distance may even exceed 30 m, and the maximum length is mainly dependent on the type of the PoE power supply used to power the access point (AP).
Below there are examples of APs with integrated antennas. One of them operates in the 2.4 GHz, the second in the 5 GHz band.
Access Point TP-LINK TL-WA5210G (outdoor)
Outdoor access point TL-WA5210G High Power 2.4 GHz can operate in AP, AP Router, WISP, or WISP Client mode. The device is equipped with a high gain antenna, which, together with the electronic board, is put in a weather-resistant housing. Thanks to the antenna with 12 dBi gain, high output power of the transmitter (27 dBm) and high sensitivity of the receiver, the device allows to create long-range, stable and efficient wireless connections.
TP-LINK TL-WA5210G N2350
Access Point SEXTANT G-5HnD (5GHz MikroTik 18dBi 25dBm MIMO 2x2 802.11a/n)
RouterBoard SEXTANT G-5HnD uses MIMO 2x2 technology. The AP operates in the 5 GHz band and its dual-chain antenna using MIMO 2x2 technology has 18 dBi gain. The integrated wireless module with 25 dBm output power is compliant with 802.11n standard. The 10/100/1000 Mbps Ethernet interface and Mikrotik RouterOS Level 3 system allow for the effective use of the MIMO 2x2 technology. The platform is consistent with MikroTik NV2 TDMA protocol which allows for higher bandwidth compared to the 802.11n standard.
SEXTANT G-5HnD 5GHz N24113
Building a new house - the choice of structured cabling. Due to technological developments, changes of the offered services, as well as technical innovations emerging on the market, the selection of the cabling for home system is not easier than before. Faced with the task of designing the wiring for the access to the Internet, the designer must take into account several factors that may influence the ultimate layout of the network. Insufficient number of cable links or inadequate kind or category of the of the cables can cause significant limitations in the future. On the other hand, it is necessary to consider the economics of the project and not plan too many cables which may never be used. So, how to wire the house at the current level of technology?
Cable selection. The basic transmission medium used for the construction of a home LAN should be copper twisted-pair cable. The use of fiber optics for home transmission systems seems not to be justified even in the perspective of 10-20 years. In most cases the sufficient medium is a cat. 5e twisted-pair cable. This type of cable supports data transfer speeds of up to 1 Gbps, which should be satisfactory for home users even for decades. More "ambitious" home owners may consider laying twisted pair category 6 cables, which will enable data transmission speeds up to 10 Gbps. Another issue is the choice between the unshielded twisted pair cable (UTP) and the shielded version. It would seem that the more expensive shielded cable is always the better option, but it should be remembered that the use of such a cable imposes shielding of all components such as wall sockets (including grounding) and active devices (which have to be equipped with shielded ports). Considering the higher price of the equipment, additional installation costs, and the fact that the electromagnetic interference from the unshielded cables is not significant in the home environment, the preferred choice is usually the UTP cable.
Cabling solution for a home LAN
Green lines ⇒ E1171 - 50 Ω Tri-Lan 240 coaxial cable
Violet line ⇒ E1410 - NETSET U/UTP 5e gel-filled outdoor cable (black)
Red lines ⇒ E1408 - NETSET U/UTP 5e indoor cable
Blue line ⇒ ISP cable
Topology - the layout of the cables. The optimum solution is when cables are provided to all rooms in the house. This will allow for free selection of the location for a wireless AP in order to ensure access to the Internet throughout the whole house (or, if one AP is insufficient for full coverage, finding a place for a second AP in another room). The possibility of connecting a PC or other device to the wired network in any room is also a great advantage. So far, cable connections provide maximum stability, which may be very important in some applications, such as streaming of high-definition video or online gaming. When planning the wiring, the owner of the house and the designer should remember that today the Internet is used not only on personal computers. The LAN should also be connected to smart televisions, home theater, game consoles. A socket in the kitchen or even in the bathroom is not an exaggeration, either.
Connection to WAN. Creating the home LAN, the owner and designer should take into account all potential Internet service providers (ISPs) in the area. The cabling available on the lowest level of the building will allow for easy connection to services from local ISPs such as telephone or CATV operators. The termination of the LAN on the roof (with one outdoor UTP cable) will allow for the use of services from ISPs providing to the Internet by radio means (after installing on the roof an AP integrated with antenna). Another option is the increasingly more popular LTE technology. Two coaxial cables (50 Ω) provided to the roof will enable installation of an LTE antenna supporting MIMO technology and taking full advantage of high-speed Internet provided by a cellular operator.
Intercom function in Hikvision NVRs. Hikvision DS-7604NI-E1 K2204 is a modern IP network video recorder capable of monitoring, recording and playing back images from four megapixel IP cameras at frame rates up to 25 fps from each camera. The NVR has audio input and output, which enables two-way audio communication between operators or between an operator and anyone by a camera with built-in or external microphone (connected to the audio input on the camera). The video from the IP cameras plus bidirectional audio information is transmitted according to IP protocol as a data stream, thus it can be easily distributed e.g. between buildings (in LAN network) or over longer distances (on the Internet). The intercom functionality can be used by operators for convenient voice communication, for rapid response in the case of incidents etc. To allow the communication, the AUDIO OUT of the NVR has to be connected to an active loudspeaker (with built-in amplifier) and the AUDIO IN to a suitable external microphone. If the monitor connected to the NVR has built-in speakers, there is no need for an external speaker (the monitor can be connected via HDMI cable, or VGA cable and audio cable). Of course, the second surveillance post must also be equipped with a microphone and a speaker. A diagram illustrating voice communication between two posts is presented below.
19PoE Switch: ULTIPOWER 0098af (9xRJ45, 8xPoE 802.3af)Vandal-proof IP Camera: Hikvision DS-2CD2312-I (1.3MP, 2.8 mm, 0.01 lx, IR up to 30m)
The use of intercom function in an IP CCTV system
Visualization of CCTV coverage with E-map. In the case of extensive video surveillance systems the operator should know exactly the layout of the camera points. It is necessary for quick identification of the monitored areas. The IVMS-4200 client software supplied with Hikvision DVRs enables the user to import layouts of buildings and field maps as JPEG/bmp files. The plans will be the backgrounds for placing on camera symbols, in compliance with their actual locations.
E-map window in a CCTV system based on Hikvision DVRs/NVRs
Each camera point can be correlated with specific alarm event, such as motion detection. When the alarm is triggered, a siren symbol by the camera icon informs the operator about the event. Double-click on the camera symbol allows the operator to quickly monitor the area and assess the situation. With a large number of cameras, E-map enables the operator to find out whether the alarms come from neighboring cameras and to follow the intruder. The E-map application is compliant with analog cameras connected to DVRs as well as with IP cameras (can be used in analog, hybrid, and IP CCTV systems).
New products offered by DIPOL
All-in-one Compression Tool MASTER (for BNC, F, IEC, RCA)
All-in-one Compression Tool MASTER E80075 is a multipurpose tool suitable for compressing F, BNC, RCA, and IEC compression connectors. This compact and durable tool is made from the highest quality materials and has been designed with the emphasis on the ease of use.
Building Amplifier: Terra HS-200 (split-band)
Building Amplifier HS-200 TERRA R82309 is designed to amplify FM radio and TV signals in the VHF and UHF bands (split-band structure). It can provide high output levels (118 dBμV for the VHF band and 121 dBμV for the UHF band), suitable even for large passive distribution networks with dozens of outlets. The gain in UHF band can reach 56 dB.
Combination CO and Smoke Alarm Kidde 10SCO
Combination CO and Smoke Alarm Kidde 10SCO G9995 is a battery-powered combination alarm that offers protection from the dual dangers of smoke and carbon monoxide (CO) in a single unit. The detector has two separate sensors, an optical sensor for smoke detection and an electrochemical sensor for carbon monoxide. Its voice alarm feature audibly announces which danger has been detected (in English). This is combined with a loud 85 dB alarm and red-blinking LED alerting the users about the potential danger. A unique feature of the device is End of Life Warning Signal that alerts the users when it’s time to replace the unit after 10-year protection period. Within that period, the user should only change the battery after each low battery alert.
Worth reading
Optical fibers in installation boxes. The transition from copper to fiber optic systems may seem difficult for many installers of low voltage systems. The habits resulting from the experience gained by many years of practice with copper systems often turn out to be a big problem in the case of optical networks. One of the fundamental skills that any FTTx installer must develop, is the due diligence in arranging optical fibers. This applies to running cables through wells, walls, conduits and protective pipes, and their termination in distribution frames and installation boxes. The latter task is usually the most difficult one... more
he arrangement of fibers in and splices L54041 box.
The figure on the left shows the tray with the incoming cable, splices, and pigtail.
The drawing on the right presents the lower part of the box (the tray has been pivoted)
with the cable fitting, adapters and connectors.
Transmission over loooong distances - fiber optic equipment
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