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No. 16/2020 (April 20, 2020)
A radio telescope in outer space.
NASA has announced plans to use a crater on the surface of the moon to deploy a giant 1 km radio telescope. The lunar crater radio telescope (LCRT) would rely on wavelengths greater than 10 m (e.g. frequencies below 30 MHz) to peek into outer space. This would not be possible down on Earth since these wavelengths are reflected by its ionosphere.
Notional view of LCRT on the far-side of the Moon.
According to NASA's proposal, a 1km-diameter wire-mesh would be deployed using wallclimbing DuAxel robots in a crater (with a diameter of up to 5 km) on the far-side of the moon, and a receiver would be suspended above the crater floor. Importantly, the entire building process would be completed remotely (without the need to transport people to the moon).
The proposal is now at an early review stage and no particular crater has been chosen for the purpose. It is worth noting that the largest radio telescope currently in use on Earth has a diameter of 500 m, i.e. half the size of the projected LCRT. It is located near the Chinese city of Pingtang.
Hikvision IP cameras with the RTMP protocol.
Selected models of Hikvision's IP cameras come with a direct YouTube streaming function. In order to send audio and video directly, the camera must support the RTMP protocol and have a built-in microphone or audio input that can be connected to an external audio source. Streaming is also possible with cameras that do not support RTMP, provided that the stream is converted using a dedicated software, such as eg. OBS Studio. An updated list of cameras that support the RTMP protocol after an upgrade to the dedicated firmware, available from DIPOL in the "Download files" tab, can be found here.
RTMP stream configuration window in a DS-2CD2643G0-IZS K17856 camera
How does lens aperture affect camera image?
The iris is the part of the lens through which light reaches the camera's sensor. The larger its aperture, the more light can reach the light-sensitive components. This allows for the image to be captured even in reduced lighting conditions. The size of the aperture is given by a figure expressed as f/x or Fx (x is the shutter number).CCTV cameras are usually equipped with F1.0, F1.4, or F2.0 lenses. F1.0 responds to the largest aperture, F1.4 – half of it, and F2.0 – four times smaller.
An F1.0 lens admits the greatest amount of light and is used in Hikvision products from the ColorVu line as part of the TurboHD 5.0 offer. ColorVu cameras stand out for their high sensitivity (0.0005 lx) and can generate a color image even in low-light conditions: all they need is light from street lamps or the moon.
Why, then, is F1.0 not used across the board? The manufacturing costs of F1.0 are higher than those of the most common F1.4. But that is not all: another important parameter is the depth of field (DOF), which defines the distance range, within which object are in sharp focus in the image (i.e. have clear, not blurry contours). The higher the f-number, the smaller the opening through which the light filters in and the greater the DOF. In ColorVu cameras, the depth of field is slightly reduced.
Remote PoE switch power supply.
The ULTIPOWER 352SFP N299707 PoE switch is equipped with a PD (Powered Device) function, which allows it to be powered from another PoE switch. The feature is extremely useful especially when the switch (or cameras, if they are mounted in the same spot, e.g. on a pole) is located in places linked only by a twisted pair cable.
A PoE switch with the PD function
In addition, the switch has the following functions:
- Extended mode, which allows for connecting PoE devices over distances up to 250 m,
- PoE Auto Check function for the automatic power restart of a non-responsive device.
HDMI to DVB-C conversion.
Modulators can be divided into categories based on a number of criteria. One of the most basic is the type of signal at the RF output. The criterion allows to distinguish between DVB-T and DVB-C digital modulators. Further criteria have to do with e.g. the number of sources that can be connected to a single device, output RF channels, and, for DVB-T modulators, the number and type of inputs.DIPOL's portfolio of digital modulators has recently been expanded to include two new models: TERRA MHD003P HDMI-1xQAM (DVB-C) R86105 and TERRA MHD004P HDMI-1xQAM (DVB-C) R86106 with the HDCP protocol. The devices stand out for the high quality typical of the brand's products, low cost, and a small size that facilitates installation.
MHD003P R86105 and MHD004P R86106 modulators are multifunctional devices that encode and modulate input HDMI signals with a Full HD resolution (1920x1080-30p) into the DVB-C QAM channel. The modulators have an HDMI input, an RF input, a 12 VDC input (a DC jack inside an F-like socket - the device cannot be powered via a coaxial cable). In addition, the MHD004P R86106 model features an HDMI output.
Why should you bet on ULTIMODE quick connectors?
Many installers fear using optical fibers because of the challenges of their termination, i.e. the need to buy a fusion splicer or contract a company that provides such services. A quick, cheap, and reliable solution is offered by DIPOL's ULTIMODE quick connectors.Easy to mount and reliable, ULTIMODE connectors are characterized by two structural features:
- advanced positioning of the inserted fiber end by V-shaped grooves - the face of the fiber with a diameter of 125 microns is exactly matched with the face of the fiber section integrated into the connector,
- fiber locking in two points - the precisely matched fiber is blocked at two points, which ensures the stability and durability of the connection.
ULTIMODE FAST connectors
A: fiber positioning in V-grooves
B: 2-point fiber locking system
A: fiber positioning in V-grooves
B: 2-point fiber locking system
 | Rechargeable battery: Acumax AML 18-12 M18867 uses cutting-edge AGM technology, where the electrolyte is absorbed in highly porous fiber glass separators placed between the plates. This eliminates the risk of leakage and allows the batteries to work in any position. | |
 | Ceiling IP Camera: Hikvision DS-2CD2347G1-L K00311 is an ideal solution for all those who wish to expand their CCTV systems to include a camera that allows to monitor the scene in the color mode around the clock and thus detect all the necessary details. The camera has been fitted with a 4 MP 1/1.8" Progressive Scan CMOS sensor manufactured in the BSI (Backside Illumination) technology, which stands out for its ultra high sensitivity and ability to capture the image even in very low-light conditions. | |
 | Thermographic Turret Camera: Hikvision DS-2TD1217B-3/PA(B) K01848 is a thermographic turret camera dedicated for the real-time measurement of body temperature with high accuracy (+/- 0.5°C and +/- 0.3°C using a blackbody calibrator) within the 30°C to 45°C range. Thanks to its high accuracy, the camera can be used to detect individuals with elevated body temperature caused by e.g. a fever-inducing infection. | |
Worth reading
Fever-screening cameras. In response to the current coronavirus threat, Hikvision has prepared a number of solutions that use thermal cameras to carry out precise temperature measurements in the 30° - 45°C range, with up to 0.5°C or 0.3°C accuracy (using a blackbody calibrator)...>>>more
All bodies with temperatures above absolute zero (0 K = -273.15 °C) emit infrared radiation. Based on the relationship that exists between radiation intensity and temperature, a thermal camera that picks up infrared rays is able to use their wavelengths to calculate the temperature of an object. The devices allow users to see the distribution of temperatures on the surface of a given body and meausre their values.
Vertical mounting system in 19" RACK cabinets
