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No. 13/2019 (April 1, 2019)
See NASA astronauts walking in space.
On March 22, it took place the first of three space walks planned for the next three weeks, performed by astronauts from the International Space Station in order to replace old batteries used in the solar panels of the station. For the first time in history, it was two female astronauts from NASA, Anne McClain and Christina Koch, who went outside the station. The astronauts were working on improving the space station power system. Twelve old nickel-hydrogen batteries were replaced with six larger lithium-ion batteries. The broadcast from this event could be watched live on YouTube.The batteries on the space station store the energy generated by solar panels and power the station when it is on the dark, night side of the Earth. Just like batteries in cell phones, the aging batteries in the space station were reducing their capacity. The battery pack used so far had been operating at the station for almost 12 years, and the new batteries should last for the rest of the space station's life. NASA plans to end the space station program in 2024.
NASA TV is a YouTube channel where you can often watch live broadcasts from the space station,
from a camera directed to Earth. Live streaming of astronauts' activities is something completely new.
On April 8, the third and last walk of the series will take place, this time staffed by men, also available for viewing online. NASA provides a number of other live reports from press conferences and rocket launches, as well as it broadcasts many educational programs on a regular basis. In the United States, the NASA public transmissions and broadcasts are available from the AMC-3 satellite (87°W, 4 GHz C-band, polarization H, MPEG-2 at 28.1111 Msps).
Two satellites via four cables – Wide Band technology.
Multiswitch SMATV systems with quatro LNBs receiving signals from two satellites (e.g. HotBird 13.0E and Astra 19.2E) have to use 8 coaxial cables (RG-6). A Wide Band LNB (e.g. A98222) has two outputs (H and V polarizations) and the distribution of signals from two satellites requires only four coaxial cables between the LNBs and the suitable multiswitch, reducing by half the number of the cables. With single local oscillators operating at 10.41 GHz, such LNBs provide much wider intermediate frequency band (290...2340 MHz) than conventional (legacy) LNBs.The Wide-band LNB A98222 cooperates with Terra SRM-581 R80581 dSCR multiswitch that has 5 inputs. Two pairs of SAT IF inputs (V1, H1, V2, H2, 290...2340 MHz) should be connected to two Wide-band LNBs A98222, the fifth input (of active terrestrial path) is intended for DVB-T, DAB(+) and FM radio signals. The AGC system ensures stable 84 dBμV output level, and the die-cast housing provides high screening efficiency (class A). In dSCR mode, each of the eight Legacy / dSCR +Terr.TV outputs allows for independent operation of up to 16 SAT dSCR receivers/STBs (EN50607) fed via one coaxial cable, or, in the Legacy mode, can be connected to a legacy SAT TV receiver, in exactly the same way as an output of a Universal LNB or of a standard (legacy) multiswitch.
The SRM-581 R80581 multiswitch has been equipped with efficient AGC system stabilizing the output level at 84 dBμV. This means that the installer does not have to worry about signal level adjustments of the multiswitch - it is sufficient to provide input signals at levels within the required ranges.
An example of SMATV system distributing satellite channels in dSCR/Unicable technology, along with amplified terrestrial broadcasts. In dSCR mode, each of the eight Legacy / dSCR +Terr.TV outputs allows for independent operation of up to 16 SAT dSCR receivers/STBs (EN50607) fed via one coaxial cable. Each satellite receiver in the installation has an assigned User Band (UB) with bandwidth approximately the same as a satellite transponder. The receiver determines which input frequency from the Ku band is selected and converted to the UB. The selection is performed with DiSEqC command from the receiver (from among up to 8 signals that can be delivered by one cable - EN50494, or from among up to 32 signals - EN50607.
Monitoring of an apartment building, based on Hikvision EasyIP 2.0plus cameras.
The following figure shows a concept of a video monitoring system covering such a building, based on a Hikvision NVR and IP cameras from the EasyIP 2.0plus series. The outside area around the building is monitored by eight DS-2CD2043G0-I K17635 compact cameras with 4 MP resolution and 2.8 mm lens with 98° viewing angle. Inside the building there are four ceiling cameras DS-2CD2123G0-I K17321 with 2 MP resolution, equipped with 2.8 mm lenses with 114° viewing angle. Both models of the cameras have IR illuminators with range up to 30 m made in EXIR technology ensuring even lighting of the scene at night. The layout of the cameras allows for good identification of any potential vandals who might destroy the facade of the building.The cameras are powered and connected to the NVR via the N29986 16-port PoE switch. The cameras of the EasyIP 2.0plus series support H265+, H.265, H.264+, H.264 video compression. With the use of two 3 TB hard drives, e.g. M89285, H.265 video compression and continuous recording mode at 25 fps for each camera, the data retention time is 15 days.
Schematic diagram of IP CCTV system based on Hikvision devices in an apartment building
The video streams from the cameras are recorded by 16-channel IP NVR DS-7616NI-K2 K22165. The images can be viewed locally and played back on the M3022 monitor. Additionally, after connecting the NVR to the Internet via the N3259 router, the access to the system is possible via Wi-Fi (within the range of the wireless router) and through the Internet (after forwarding ports or using cloud solution). The cabling is made of the E1408 cable.
How to improve LTE connectivity.
In many cases when a base station is far away from the mobile device, there are problems with the appropriate signal strength. In order to improve it, the best way is to connect to the modem an external antenna.Before choosing an outdoor antenna, the user should check out parameters of the signal received by the LTE modem. Usually it can be done by running a network diagnostic panel offered by the software of the router or modem. The parameters should be compared with the values shown below.
- RSRP (dBm) - (Reference Signal Receive Power) - measure of the signal strength.
- more than -79 dBm - very good signal strength,
- from -80 dBm to -90 dBm - good signal strength,
- from -91 dBm to -100 dBm - poor signal strength. Need for an outdoor antenna or finding a better location of the modem
- less than -100 dBm - very poor signal strength. It is necessary to use an outdoor antenna
- RSRQ (dB) - (Reference Signal Received Quality) - measure of the signal quality.
- more than -9 dB - very good,
- from -10 dB to -15 dB - good,
- from -16 dB to -20 dB - bad. Need for an outdoor antenna or finding a better location of the modem
- less than -20 dB - very bad It is necessary to use an outdoor antenna
- SINR (dB) - (Signal to Interference plus Noise Ratio) - measure of signal quality with respect to interference.
- more than 21 dB - very good,
- from 13 dB to 20 dB - good,
- from 0 dB to 12 dB - bad. It is necessary to use an outdoor antenna
- less than 0 dB - very bad.It is necessary to use an outdoor antenna
- RSSI - Received Signal Strength Indicator
- more than -73 dBm - very good,
- from -75 dBm to -85 dBm - good,
- from -87 dBm to -93 dBm - bad. Need for an outdoor antenna or finding a better location of the modem
- less than -95 dBm - very bad. It is necessary to use an outdoor antenna
A popular broadband antenna improving connectivity in LTE bands
ATK-LOG ALP LTE MIMO 2x2 800-3000MHz A7054
ATK-LOG ALP LTE MIMO 2x2 800-3000MHz A7054
Capacity of a rechargeable battery.
The main parameters of each rechargeable battery are the rated voltage and capacity. Due to the fact that the capacity of a battery depends on the discharge conditions, the value is normally given for a 10-hour full discharge current. For example, if the battery has a capacity of 20 Ah, it means that the load can take 2 A for ten hours. To determine how long the battery can supply a real system, one should know the actual current consumption and compare it with the characteristics of the battery for a similar discharge current.
Discharge time vs. discharge current - Securbat CB 7-12 SB M1883
Discharge time vs. discharge current - Securbat CB 17-12 SB M1885
Beginners should familiarize themselves with the article in order to avoid simple errors that may reduce the quality of splices made, as well as to reduce the time necessary to perform specific tasks. Typical mistakes made by people who do not take the time to get acquainted with the splicer and the principles of its configuration and operation:
- no calibration of the arc before splicing - this may result in splices with increased attenuation, or worse, with reduced durability,
- using an incorrect splicing program for a given type of fiber,
- not disabling functions that are not used, but which discharge the battery (e.g. automatic activation of the heater after 6 seconds after splicing,
- negligence in updating the splicer's software.
 | Compact IP Camera: Hikvision DS-2CD2T46G1-2I K04521 is dedicated for professional IP CCTV systems. The ceiling camera has been equipped with high quality 4 MP 1/2.7" CMOS sensor providing good video coverage even in very low-light conditions. Along with IR illuminator with range up to 50 m, the camera can also operate in complete darkness. The built-in 2.7 mm lens has 104° viewing angle. The IP67-rated housing of the camera protects the electronics against adverse weather conditions. The camera can be powered conventionally with a 12 VDC source or with the use of PoE option (802.3af). | |
 | F-female to quick F-male adapter (straight) E8247 can be a useful item in the pocket of any antenna installer. | |
 | Ceiling IP Camera: Hikvision DS-2CD2126G1-I K00413 is dedicated for professional IP CCTV systems. The ceiling camera has been equipped with high quality 2 MP 1/2.8" CMOS sensor providing good video coverage even in very low-light conditions. Along with IR illuminator with range up to 30 m, the camera can also operate in complete darkness. The built-in 2.8 mm lens has 108° viewing angle. The IP67-rated housing of the camera protects the electronics against adverse weather conditions. The camera can be powered conventionally with a 12 VDC source or with the use of PoE option (802.3af). | |
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