CZ
PL
EN
DE
IE
HU
PT
RO
SK
ES
No. 20/2015 (May 18, 2015)
Battery-operated homes?
Tesla Motors - US car company, producing, among others, electric sports cars, officially presented its latest product - Powerwall home battery to store surplus solar energy for later use. Tesla proposes the use of solar energy also in the morning and in the evening, when the sunlight is weak, and the demand of household appliances is the greatest. During the day, the solar energy transformed by photo-voltaic panels flows directly to the home appliances, and its excess is charging the Powerwall battery. After sunset and in the morning the accumulated energy is used as domestic power supply.Powerwall can be placed indoors or outdoors and can operate within -20...+40oC temperature range. It can be mounted on any wall in the home or garage and is completely maintenance-free. Such batteries can be installed together, in a set of up to 9 pieces.
Tesla Powerwall lithium-ion battery has dimensions of 130 cm by 85 cm by 18 cm and weights about 100 kilograms. So, it is not the smallest "home appliance", but considering the parameters offered, both the dimensions and the weight should be regarded as relatively small. The battery packs are available in two versions, with a capacity of 7 kWh, for daily cycle applications, and 10 kWh, for backup applications. They can be used to power all appliances in the home or office, and also provide protection in the case of power outages. Powerwall is charged by photovoltaic panels, and if the solar energy supply is insufficient, from the utility grid.
uSwitch company estimates that energy of 1 kWh is sufficient for two-day operation of a laptop, or one economical wash cycle, or for boiling ten times water in the kettle. An important advantage of Powerwall batteries are attractive prices, much lower than in the case of other "mega-batteries". The model with the smaller capacity costs about 3000 USD, and the second 3500 USD.
Masthead DVB-T amplifiers with LTE filters.
TERRA company, the European leader of equipment for TV and FM/DAB antenna systems, has introduced new masthead amplifiers AB010L R82015 and AB011L R82016. These top class devices are dedicated for use in individual and small shared antenna systems (with ten or so outlets). The gain in the whole UHF band used in DVB-T (470-790 MHz) is 14 dB or 26 dB, respectively, with very low noise, below 1 dB. The AB010L R82015 and AB011L R82016 amplifiers have built-in LTE filters (791- 862 MHz), so they can be used in environments where LTE services cause problems with the reception of DVB-T broadcasts. They can be powered from 12 VDC sources, or directly from the inputs of DVB-T receivers (5 VDC, compatibility with DVB-T standard - EN 300 744). All TERRA devices come with a 4-year warranty.
Products marked like above have been equipped with LTE filters,
i.e. they strongly attenuate signals at frequencies above 790 MHz
i.e. they strongly attenuate signals at frequencies above 790 MHz
 |  | |
| Name | AB010L | AB011L |
| Code | R82015 | R82016 |
| Operating band [MHz] | 470-790 | |
| Gain [dB] | 14 | 26 |
| Number of inputs | 1 | |
| Number of outputs | 1 | |
| Noise figure [dB] | 0.8 | < 1 |
| Max output level [dBμV] | 98 | 108 |
| Interstage gain adjustment [dB] | - | 13/26 |
| Return loss [dB] | > 10 | |
| Power consumption [V x mA] | 4.5-12 x 30 | 4.5-12 x 60 |
| Operating temperature range [°C] | -20...+50 | |
| Dimensions / Weight [mm/kg] | 89x107x43 / 0.18 | |
What is the meaning of the symbols on a computer twisted pair cable?
Acronyms for balanced cables are standardized by ISO/IEC 11801:2002 (Annex E). The information contained in the cable description should have the following syntax: xx/yyTP, where the letters yy characterize individual wires/pairs and the letters xx describe the overall construction of the cable.The xx and yy markings can be as follows:
- U – unshielded
- F – foiled (screened with foil)
- S – shielded (screened with braid)
- SF – shielded and foiled
Typical balanced cables:
- U/UTP – unscreened cable
- F/UTP – foil screened cable with unscreened balanced elements
- U/FTP – unscreened cable with foil screened balanced elements
- F/FTP – foil screened cable with foil screened balanced elements
- SF/UTP – overall braid and foil screened cable with unscreened balanced elements
- S/FTP – overall braid screened cable with foil screened balanced elements
- SF/FTP – overall braid and foil screened cable with foil screened balanced elements
DIPOL sells the following range of twisted pair cables:
- CAT 5e UTP Cable NETSET BOX U/UTP 5e, indoor - E1408_305
- CAT 5e FTP Shielded Cable NETSET BOX F/UTP 5e, indoor - E1515_305
- CAT 6 UTP Cable NETSET BOX U/UTP 6, indoor - E1608_305
- CAT 5e UTP Cable: NETSET BOX U/UTP 5e, outdoor - gel-filled, black - E1410_305
- CAT 5e UTP Cable NETSET BOX U/UTP PE, outdoor, black - E1412_305
Welding of optical fibers - preparation of fiber ends.
Regardless of the choice of a welding machine, the fusion splicing process is quite similar, with a series of steps. The first of them is the removal of the fiber coating, 250 μm or sometimes 900 μm. Independently from the type of the spliced fibers, the bare cladding has diameter of 125 μm, the size needed for further operations. Then, it is necessary to clean the fibers with isopropyl alcohol (normally with dust-free wipes or cotton swabs), and cleave them using a suitable cleaver. The latter operation is very critical - it is important to ensure both the appropriate length of the fiber ends (in most cases the installer does not have anything to measure, because the construction of the cleaver allows for easy selection of the suitable length) and perfect angles of the cleavage planes. In practice, the welders accept some deviation from the right angle (about 1 degree), but more precise cleaving will result in better performance of the fusion splices. Low quality cleaver or insufficient accuracy of this operation are the main reasons of lower quality of the splices. |  |
The removal of the 250 μm coating and fiber cleaning
 |  |
Fiber cleaving. The fiber scraps have to be put into dedicated trash can for utilization.
After placing the fibers in the welding machine, the results of the previous operations are verified. In the case of an excessive dirt on a fiber end face or improper cleaving, the device will notify the user to repeat the fiber end preparation process. When everything is in order, the fibers are welded with the use of an electrical arc, and the fusion splice is tested for strength and transmission parameters (loss).
 |  |
Before splicing: inspection of the cleaving angles and the offset of the fibers | After splicing: estimation of the splice loss |
The process of joining fibers usually takes several to about ten seconds. The next and last step is the protection of the splice with a heat-shrinkable sleeve, with the use of a heat oven, which is often integrated with the fusion splicer. Newly made splices are fragile and always require additional protection. Heat-shrinkable sleeves protect them mechanically and allow for easy placement of the connected fibers in splice cassettes.
Connecting analog cameras to IP CCTV system.
In the case of expansion or modernization of CCTV systems, it often happens that they consist of two subsystems: analog (with coaxial cabling) and IP (connected to LAN). The both networks can be integrated using hybrid DVRs. The old analog cameras and DVRs can also be replaced by the Hikvision HD-TVI equipment (HD-TVI cameras, HD-TVI DVRs) that, using the existing coaxial cabling, can provide full HD image resolution. The analog HD-TVI DVR can be used as an expander for an IP NVR, in order to provide the images from the analog cameras to the IP system. The IP NVR should have sufficient number of channels that can be used by the analog subsystem (e.g. a 32-channel IP NVR, with 8 channels reserved for the 8-channel HD-TVI DVR). In the case of Hikvision devices, the analog DVR will not be discovered automatically, so it should be added manually in the camera configuration window of the IP NVR, by entering:- IP address of the analog DVR
- protocol: Hikvision
- port: 8000
- required channel (camera) of the analog DVR
- user name: admin (default)
- password: 12345 (default)
The architecture of an IP CCTV system with HD-TVI subsystem
Each analog channel is assigned to a specific channel of the IP NVR. With 8 analog cameras, the HD-TVI DVR has to be added 8 times, each time with pointing a specific channel (camera). The recordings from the analog cameras can be stored only on the analog DVR or on the IP NVR, or on both devices simultaneously, which guarantees maximum reliability of the system in case of a disk failure. Thanks to the same communication protocol, the administrator of the system can control the functions of the analog DVR directly from the IP NVR interface (e.g. motion detection).
Transmission of HD-TVI signals via twisted pair cables.
The application of a UTP/FTP cable instead of coaxial cable has important advantages. The installation of the twisted pair cables is easier due to their flexibility and versatility - one cable containing four pairs can transmit signals from more than one camera and/or be also used for power supply. The application of the twisted pair for video transmission is connected with the use of impedance matching devices, i.e. matching the 75 Ω unbalanced impedance of analog CCTV systems to the 100 Ω balanced impedance of the twisted pair, located on both sides of each video transmission line. HD-TVI systems require the use of dedicated transformers (baluns) that are capable of operation in a broader frequency band compared with "classic" systems transmitting CVBS signals. The example of an HD-TVI video balun is Hikvision DS-1H18 M16641. In the case of a UTP/FTP cat. 5 cable, the transmission line can reach 150 meters (signals from HD-TVI, HDCVI, AHD cameras) or 400 meters (signals from CVBS cameras).
HD-TVI Video Balun Hikvision DS-1H18 (2 pcs., BNC) M16641
The use of baluns designed for CVBS signals for transmission of video from an HD-TVI camera would cause deterioration of the image quality or even could completely block the transmission. In the case of short transmission lines (up to 100 meters), the "old" baluns can be sometimes "good enough" for connecting HD-TVI cameras with resolutions up to 720p.
 | HD-TVI TURBO HD camera Hikvision DS-2CE16C2T-IT3 M7565 - compact camera designed for use in CCTV systems based on HD-TVI DVRs. The camera provides 720p video. With high sensitivity (0.01 lx) and built-in IR illuminator with range up to 40 m, the camera ensures high quality image in low light or even no-light conditions. | |
 | LTE rejection filter Terra LF002 (pass band 5-790MHz) R82012 is used in TV antenna systems. The filter cuts off the unwanted part of the UHF spectrum (791-862 MHz) reserved for data transmission in mobile networks (LTE). The device is especially recommended for systems with broadband amplifiers covering the whole UHF band (up to 862 MHz). In such systems, the interference from the unwanted signals can completely block the reception of some DVB-T multiplexes. | |
 | HD-TVI TURBO HD DVR Hikvision DS-7208HQHI-SH (8ch) M75308 is a 8-channel tribrid CCTV DVR capable of recording surveillance video provided in HD-TVI, CVBS and IP standards. The maximum recording resolution is 1080p@25fps. In the case of 720p / VGA / WD1 / 4CIF / CIF resolutions, the maximum frame rate is also 25 fps. | |
Worth reading
Cable attenuation compensation in multiswitch systems. The coaxial cable attenuation increases with frequency. This means that higher TV channels and especially satellite broadcasts converted into higher SAT IF frequency ranges are attenuated more than those transmitted in the lower bands. This effect can be compensated by a gradual increase of the gain for higher frequencies - the TERRA SA series of multiswitches has been equipped with adequate mechanisms. Since the attenuation characteristics of various cables can differ, the so called "Slope" parameter is adjustable (it should take values appropriate for specific cable types/brands) with potentiometers or switches. As the result, the gap between the signal levels of the lowest and highest channels or frequencies in subscribers' outlets is minimized. The graphs below show the difference in signal levels in a subscriber outlet (cable length of 70 m) before and after using the compensation mechanisms implemented in the SA-901 R70901 amplifier ... >>>more
The result of the "Slope" correction in the SA-901 R70901 amplifier
(cable length 70 m, on the left - without compensation, on the right - "Slope" set at 12 dB)
(cable length 70 m, on the left - without compensation, on the right - "Slope" set at 12 dB)
DVB-T modulator Signal-400
