2.3. Transmitter Types 3. Typical Radar System Applications and Block Diagrams 1. Magnetron tubes 3.1.2.2.2.4. Basic Characteristics of Receiver 2.2.2. Dual Klystron Radar System 1. General Overview 1.4.4.2.1.1.3.2.2.6.2. General Overview 3. Dual-Polarization Klystron Radar System 2. Low Noise Amplifier (LNA) 2. RECEIVER 3 5 7 9 9 12 12 12 13 13 14 14 15 15 19 20 20 22 22 23 23 24 25 25 28 28 29 30 31 31 32 3 2.2. Travelling Wave Tubes (TWTs) 3.0 / ALANYA 2005 .5.5.MODULE B RADAR HARDWARE RADAR HARDWARE CONTENTS CONTENTS FIGURE LIST TABLE LIST 1.1.2.5.5.1. TRANSMITTER 3. Oscillators 2. Dynamic Range 2. Solid State Power Amplifiers 3. Gyrotrons 3.2. General Overview 2. OPERATION PRINCIPLES OF WEATHER RADAR 1.3.2. RX Gain 2. One dB (1 dB) Compression Point 3.5.3. Duplexer and TR Limiter 2.5. Klystron Tubes 3. Minimum Detectable Signal (MDS) 2.3.2.4. Dual-Polarization Magnetron Radar System 1.2. Dual Magnetron Radar System 1. Single Klystron Radar System 1.5.2.1 Single Magnetron Radar System 1. Modulator TURKEY RADAR TRAINING 1.
Offset Feed Reflectors 4.3.4.4.3. RADOME 5. Antenna Pattern 4. Dual Polarization Units (in Polarimetric Radars) 4. Main Parts of a Radar Antenna 4. General Overview 4.5. General Overview 5. Waveguide and Feed Horn 4. Encoder 5.1.4.1.0 / ALANYA 2005 4 .4.MODULE B RADAR HARDWARE 4.2. Parabolic Reflectors 4.2. Antenna Types 4. Pedestal and Reflector 4.2.4. RADAR CONTROL PROCESSOR(RCP) AND RADAR SIGNAL PROCESSOR (RSP) 6.2. Rotary Joint 4. Control Processor 6. Antenna Gain 4.3.1. Antenna Control Unit. Phased Array Antenna 4.3. Servo Motors.4.3. REFERENCES VIDEO SHOW (APPLICABLE DURING TRAINING COURSE ONLY) 57 57 57 58 63 TURKEY RADAR TRAINING 1. Radome Types 6. Slipring 4. Signal processor 7.2.3.2.1. Basic Characteristics of Antenna 4.1.6. 8.1.4. ANTENNA 37 37 38 38 39 39 40 40 42 43 44 45 46 47 48 51 55 55 56 4.2.4. General Overview 6.2.2.
0 / ALANYA 2005 .MODULE B RADAR HARDWARE FIGURE LIST FIGURE 1: FIGURE 2: FIGURE 3: FIGURE 4: FIGURE 5: FIGURE 6: FIGURE 7: FIGURE 8: FIGURE 9: FIGURE 10: FIGURE 11: FIGURE 12: FIGURE 13: FIGURE 14: FIGURE 15: FIGURE 16: FIGURE 17: FIGURE 18: FIGURE 19: FIGURE 20: FIGURE 21: FIGURE 22: FIGURE 23: FIGURE 24: FIGURE 25: FIGURE 26: FIGURE 27: FIGURE 28: FIGURE 29: FIGURE 30: FIGURE 31: FIGURE 32: FIGURE 33: FIGURE 34: FIGURE 35: FIGURE 36: FIGURE 37: FIGURE 38: FIGURE 39: FIGURE 40: FIGURE 41: FIGURE 42: FIGURE 43: FIGURE 44: FIGURE 45: FIGURE 46: FIGURE 47: General Block Diagram of Doppler Weather Radar General Radar Block Diagram Another Block Diagram of Doppler Weather Radar Single Magnetron Radar System Single Klystron Radar System Dual Magnetron Radar System Dual Klystron Radar System Dual-Polarization Magnetron Radar System Dual-Polarization Klystron Radar System Some Pictures of Sub-Components of Receivers Analog Receiver Block Diagram A Basic Block Diagram of a Receiver for a Klystron Radar System A Basic Block Diagram of a Receiver for A Magnetron Radar System Inside of Receiver Hardware (IF and RF Sections) Low Noise Amplifier TR-Limiter TR-Limiter Typical Dynamic Range Curve a Receiver 1 dB Compression Point Simplified Transmitter Block Diagram Microwave Tube Family Typical Microwave Tube Characteristics and Applications Magnetron Tube Klystron Tube Diagrammatic Representation of Travelling Wave Tube Front Panel of a TX Cabinet Some Klystron Indicators High Voltage Section of aTX Monitoring Points from TX Klystron Tank A Klystron Tube Modulator of a Transmitter Inside of an Air Isolated Tank A Klystron Tube Modulator of a Transmitter Pedestal and Antenna Parabolic Dish Antenna Geometry of Offset Parabolic Dish Antenna An Offset Feed Antenna Antenna Size and Pattern (AZ Angle) Main Beam and Sidelobes Diagram of the Antenna Pedestal and Reflector Rotary Joint Some Sliprings Rotary Joint and Waveguide General Block Diagram of Dual Polarization System with Dual Polarization Switch 5 9 10 11 12 12 13 13 14 14 15 17 18 18 19 20 21 22 23 24 25 26 27 28 29 31 33 33 34 34 34 35 35 35 36 36 38 39 40 40 42 43 44 45 46 46 47 48 TURKEY RADAR TRAINING 1.
Position Resolver of Antenna. TX Cabinet. Obstruction Lights. Servo Motor 53-54 FIGURE 53: Different Types of Radome 56 FIGURE 54: Signal Processor Card 58 FIGURE 55: Signal Processor Card 59 FIGURE 56: Digitizer 59 FIGURE 57: A Radar Control Processor 60 FIGURE 58: Balıkesir Radar Site-Turkey 61 FIGURE 59: Hardware of Zonguldak Radar/Turkey 61 FIGURE 60: Scenic View of Ankara Radar/Turkey 62 FIGURE 61: General View of Radar Hardware 62 TURKEY RADAR TRAINING 1. Controller. 7m Parabolic Antenna. Cable. Antenna Pedestal.0 / ALANYA 2005 6 .MODULE B RADAR HARDWARE FIGURE 48: Dual Polarization Switch 49 FIGURE 49: Dual Polarization Switch 50 FIGURE 50: General Block Diagram of Dual Polarization System without Polarization Switch 50 FIGURE 51: Dual Polarized Parabolic Antenna 51 FIGURE 52: Some Pictures on Dehydrator. Servo Amp. Waveguide and its Tray. Antenna Control Unit and Servo Amp.. Antenna Control PCBs. Angle Detector..
SSPA CCPS SMPS PRF PRT G BW D VSWR : Stable Oscillator : Coherent Oscillator : radio Frequency : In-phase : Quadrature : Alternating Current : Direct Current : Low Noise Amplifier : Transmit-Receive : Minimum Sensitivity : Minimum Detectable Signal : Receiver : Transmitter : Decibel : Decibel Milliwatt : Logarithmic Scale for Measuring Radar Reflectivity Factor : Logarithmic : Linear : Travelling Wave Tube : Radar Control Processor : Radar Signal Processor : Azimuth : Elevation : High Voltage Regulator : Programmable Logic Control : Instantaneous Automatic Gain Control : Automatic Frequency Control : Built In Test Equipment : Antenna Control Unit : Intermediate Frequency : Input Power : Output Power : Hertz : Kilohertz : Megahertz : Gigahertz : Milliwatt : Kilowatt : Megawatt : Second : Microsecond : Solid State Power Amplifier : Capasitor Charging Power Supply : Switch Mode Power Supply : Pulse Repetition Frequency : Pulse Repetition Time : Gain : Bandwidth : Diameter of Antenna : Voltage Standing Wave Ratio 7 TURKEY RADAR TRAINING 1.0 / ALANYA 2005 .MODULE B RADAR HARDWARE ABBREVIATIONS: STALO COHO RF I Q AC DC LNA TR(T/R) Smin MDS RX TX dB dBm dBZ LOG LIN TWT RCP RSP AZ EL HV-REG PLC IAGC AFC BITE ACU IF Pin Pout Hz KHz MHz GHz mW KW MW Sec. µsec.
MODULE B RADAR HARDWARE Radome DSP PPI RHI CAPPI AR Scope : Radar Dome : Digital Signal Processor : Plan Position Indicator : Range Height Indicator : Constant Altitude Plan Position Indicator : Amplitude Range Scope TURKEY RADAR TRAINING 1.0 / ALANYA 2005 8 .
a receiver to detect and process the received signals by means of processors and a display to graphically present the signal in usable form. 1. OPERATION PRINCIPLE OF WEATHER RADAR General Overview Figure 1: General Block Diagram of Doppler Weather Radar. an RF carrier signal is generated in the receiver and fed to the klystron amplifier. The atmosphere around the radar is scanned by moving the antenna in azimuth and elevation following meteorological scanning strategies. The microwave pulse is routed through the duplexer and radiated by the antenna.0 / ALANYA 2005 9 . TURKEY RADAR TRAINING 1. During this transmit phase the receiver is blocked by the T/R limiter of the duplexer which prevents leakage from the circulator of the duplexer to the highly sensitive receiver input stages. an antenna to send the signal out to space and to receive energy scattered (echoes) by targets around. The antenna emits the transmitter pulse in a symmetrical pencil beam. The transmitter generates a microwave pulse by means of pulse-modulated amplification of the carrier signal by the klystron.MODULE B RADAR HARDWARE 1. the radar consists of a transmitter to generate microwave signal. Primarily. In figure 1 of radar with klystron transmitter.1.
After the transmit pulse is terminated. The receive phase starts and the receiver is acquiring the signals scattered by the targets. Due to its high sensitivity and its large dynamic range. receiver is capable of the detection of far clear-air echoes as well as strong signals from close thunderstorms.0 / ALANYA 2005 10 . Main units of a meteorological radar system with their basic functions are shown in the radar block diagram below.MODULE B RADAR HARDWARE Figure 2: General Radar Block Diagram. TURKEY RADAR TRAINING 1. processing units performs the tasks to convert those signals to required products to display on indicators/displays. After receipt of the echoes. the T/R limiter extinguishes and thus connects the receiver via the circulator to the antenna. The units compose the radar system and their functions will be explained in following chapters. This phase lasts until the next pulse is transmitted.
TURKEY RADAR TRAINING 1.MODULE B RADAR HARDWARE Figure 3: Another Block Diagram of Doppler Weather Radar.0 / ALANYA 2005 11 .
2. Figure 5: Single Klystron Radar System.0 / ALANYA 2005 12 . so that digital phase detection can be made with Burst IF (down converted in frequency) in the Signal Processor.2. 1. Transmitted Burst RF is fed into the RX. 1. Figure 4: Single Magnetron Radar System.2.2. Single Klystron Radar System Block diagram of the RX for single Klystron radar system is shown in Figure 5. Reference COHO (having same phase as TX RF) is output for digital phase detection processed in the Signal Processor.1 Typical Radar System Applications and Block Diagrams Single Magnetron Radar System Block diagram of the RX for single Magnetron radar system is shown in Figure 4. TURKEY RADAR TRAINING 1. Exciter TX RF is generated in the RX and fed to Transmitter to be amplified by Klystron.MODULE B RADAR HARDWARE 1.
TURKEY RADAR TRAINING 1.0 / ALANYA 2005 13 .2.MODULE B RADAR HARDWARE 1. Interswitching is performed through Waveguide Switch controlled by radar software.4. Dual Magnetron Radar System Two identical RXs for Magnetron radar are used. 1. Figure 7: Dual Klystron Radar System.3.2. Interswitching is performed through Waveguide Switch controlled by radar software. Dual Klystron Radar System Two identical RXs for Klystron radar are used. Figure 6: Dual Magnetron Radar System.
6. Figure 8: Dual-Polarization Magnetron Radar System. Dual-Polarization Magnetron Radar System Since observation is performed in both horizontal and vertical polarization simultaneously. 1. two reception circuits are composed in the RX.MODULE B RADAR HARDWARE 1. TURKEY RADAR TRAINING 1.2.0 / ALANYA 2005 14 .2.5. Thus. Dual-Polarization Klystron Radar System The system configuration is same as of Dual-Polarization magnetron radar system except a Klystron transmitter is used instead Figure 9: Dual-Polarization Klystron Radar System. COHO is also fed to IF Digitizer so that the digitizing clock is made synchronization. two STALOs (for each horizontal/vertical channel) are synchronized to the reference COHO. Higher phase stability is required for the RX used in Dual-Polarization system since it should be capable to process Differential Phase between horizontal and vertical channel for successful targets.
MODULE B RADAR HARDWARE 2. two receivers. However. Echoes of meteorological relevance span a wide range of the power spectrum say. Modern radar receivers are mostly solid-state super-heterodyne type. TURKEY RADAR TRAINING 1.0 / ALANYA 2005 15 . the information contained therein is filtered out and sent for further processing and display. After waiting for sufficient time (typically a few milliseconds). from – 110 dBm to about 0 dBm. As the signal pulse travels at the speed of light. After down conversion. 2. one with logarithmic output to handle higher power and another with linear output to handle weaker power were used. Till recently. RECEIVER General Overview Pulsed radar sends out a high-power signal for a brief duration (typically a few microseconds) and then waits for the echoes of the signal from the targets around the radar to reach the antenna. A single receiver with such high dynamic range (the difference between the weakest and strongest power that it can handle) was difficult to design. in which the received energy is mixed with a reference signal of different frequency for scaling it down in frequency for ease of processing. it does not take more than a few milliseconds for the signal to cover several hundred kilometres and get back to the radar with a wealth of information.1. the next pulse is sent out. radars with single linear receiver and dynamic range higher than 100 dB have now become available in Digital Receivers.
the STALO and COHO sections as well as the IF section with LOG channel and coherent LIN channel in Analogue Receivers. The generation of transmission frequency occurs through multiplications. The phase coherent COHO output signal serves as reference for the I/O phase demodulator which generates the coherent I and Q video signals which are fed to the signal processor. The RF front end is directly connected to the duplexer.MODULE B RADAR HARDWARE Figure 10: Some Pictures of Sub-Components of Receivers The receiver includes the RF front end. The LOG channel comprises a successive detection logarithmic video amplifier which compresses the signal and feeds it to the signal processor. the down conversion and up conversion chains. conversion and filtering of quartz oscillators signals in order to obtain very low phase noise figure and hence high Doppler performances. TURKEY RADAR TRAINING 1. It preamplifies the received scattered signals by means of a low-noise amplifier and down converts them by mixing them with the Stable Local Oscillator (STALO) to the intermediate frequency (IF).0 / ALANYA 2005 16 . In the IF section of an Analogue Receiver the signal is matched filtered and splitted into the LOG and LIN channel.
The Exciter TX RF is generated from the COHO. For a Magnetron system. the RX has the function to down-convert the Burst RF (transmitted pulse) frequency.0 / ALANYA 2005 17 . The digital approach replaces virtually all of the traditional IF receiver components with flexible software-controlled modules that can be easily optimized to the operational requirements. TURKEY RADAR TRAINING 1. to convert to IF signal with a Stable Local Oscillator (STALO). and to send it to the IF Digitizer for Digital Phase Detection.MODULE B RADAR HARDWARE Figure 11: Analog Receiver Block Diagram. The function of the RX in a Digital Receiver is to amplify the detected RF signal by Low Noise Amplifier (LNA). frequency and phase of the transmitted pulse. there is an another function that to send the exciter TX RF signal to the Transmitter (TX). Digital receiver provides better performance (wide dynamic range. so that the radar signal processor can perform the burst pulse analysis to obtain the amplitude. improved phase stability. For the RX used in a Klystron system. so that the TX transmits coherent RF which the phase is always identical. and is Pulse/Phase modulated and frequency up-converted with the STALO. etc) and higher system availability.
Figure 13: A Basic Block Diagram of a Receiver for a Magnetron Radar System.MODULE B RADAR HARDWARE Figure 12: A Basic Block Diagram of a Receiver for a Klystron Radar System.0 / ALANYA 2005 18 . TURKEY RADAR TRAINING 1.
A stable local oscillator (STALO) is also used that determines the IF frequencies and. The COHO contains a stable phase and frequency relative to the magnetron's output. Where that is achieved the system is referred to as being Coherent. Lets look at coherent on receive. clean RF carrier signal is generated by means of stabilized quartz oscillators. which are up converted by mixing and multiplication processes to form the signal amplified by the transmitter and to serve as local oscillators for the receiver down-conversion chain. To be coherent on receive one must have a COHerent Oscillator (COHO). Oscillators It is very important that the TX/ RX IF difference frequency and phase relationship be maintained within such systems. 2.0 / ALANYA 2005 19 .MODULE B RADAR HARDWARE Figure 14: Inside of Receiver Hardware (IF and RF Sections) Second trip echoes can be a serious problem for applications that require operation at a high PRF. Coherent systems employs a coherent oscillator (COHO) and a series of stages that relate TX and LO frequencies. helps to maintain coherence. therefore. Second trip echoes can appear separately or can be overlaid on first trip echoes. In the Doppler mode out-of-trip echo dealiasing and recovery is achieved by a pulse-to-pulse phase shifting of the TX signal. So. TURKEY RADAR TRAINING 1. The COHO is optionally interpulse phase-shift keyed to provide a means for the radar signal processor to distinguish between different transmit pulses for secondtrip signal recovery purposes. a permanent.2. The COHO signal is used to detect the I and Q elements of the received targets for both weather and clutter relative to Transmitted Frequency.
The LNA is a sensitive device which needs a protective circuit to prevent excess RF input which may leak from Transmitter. On transmission it must protect the receiver from burnout or damage. A duplexer must be designed for operation in the frequency band used by the receiver and transmitter. and must be capable of handling the output power of the transmitter. Solid-state devices are also utilized. Low Noise Amplifier (LNA) LNA is a module to amplify weak signal received and sent from Antenna system with Low Noise Amplifier device (LNA). the frequency separation between the transmitter and receiver.4. The RF Input terminal shall be connected to the TR-Limiter output. or less than. i. 2. directly. and must be designed to operate at.MODULE B RADAR HARDWARE 2. A TR-Limiter is normally used for the protection. sometimes employ a form of gas-discharge device. Duplexers. sometimes called as Transmit/receive switch. Duplexer and TR Limiter A duplexer. Furthermore. a duplexer must provide adequate rejection of transmitter noise occurring at the receive frequency. and on reception it must channel the echo signal to the receiver. Figure 15: Low Noise Amplifier. The duplexer is the device that allows a single antenna to serve both the transmitter and the receiver.e. especially for high-power applications.3. TURKEY RADAR TRAINING 1. is a device that isolates the receiver from the transmitter while permitting them to share a common antenna. TR tube.0 / ALANYA 2005 20 .
One common construction of a TR consists of a section of waveguide containing one or more resonant filters two glass-to-metal windows to seal in the gas at low pressure.MODULE B RADAR HARDWARE Figure 16: TR Limiter TR Limiters (Transmit-Receive Limiters) are used in antenna between the high power transmitter and the receiver. The TR tube. Pure-argon-filled tubes. is the most common receiver protector technology in use today. however. as a gas-discharge device designed to break down and ionize quickly at the onset of high RF power. The life of TR tubes filled with a mixture of a noble gas (argon) and a gas with high electron affinity (water vapour) is less than the life of tubes filled with a noble gas only. The construction of the TR tube includes one or more resonant filter sections in a piece of waveguide which is sealed at both ends with waveguide windows.0 / ALANYA 2005 21 . The deionization process can be speeded up by the addition of water vapour or a halogen. have relatively long deionization times and are not suitable for short-range applications. and offers good receiver protection and relatively long life. and to deionise quickly once the power is removed. Truncated cones form the capacitive element and irises or post the inductive element. TURKEY RADAR TRAINING 1. Each filter section is a relatively high Q parallel L-C circuit. A noble gas like argon in the TR tube has a low breakdown voltage.
this means that a storm weaker than 15 dBZ at 100 km will not be detected by the radar.5. it is the smallest input signal that will a produce a detectable signal at the output. Minimum Detectable Signal (MDS) Due to the noise generated by the receiver itself. 2. In other words in a receiver. TURKEY RADAR TRAINING 1. Those receiver characteristics are explained briefly below: 2. In other words.1. If this is about 15 dBZ for a signal at 100 km. Basic Characteristics of a Receiver The quality and the performance of receivers depend on the some basic characteristics. This is called the minimum detectable signal (MDS) or Sensitivity (Smin).MODULE B RADAR HARDWARE Figure 17: TR-Limiter. weak signals can not be identified.0 / ALANYA 2005 22 . it is the minimal amount of back scattered energy that is required to produce a target on the radar screen. MDS is a measure of the radar's sensitivity.5. In radar terms. There is thus a bottom threshold on the ability to detect echoes.
Figure 18: Typical Dynamic Range Curve a Receiver. Receiver (RX) Gain We can determine the RX gain by using the linear part of the dynamic range curve. So our RX gain= -45 dBm-(-80dBm)= 35 dB TURKEY RADAR TRAINING 1. from the minimum.5.2. RX gain can be calculated by getting the difference between output and input value at any point of that linear part of the curve.0 / ALANYA 2005 23 .PMDS Where the PMDS = Minimum detectable signal 3 dB above the noise floor. Our output is -45 dBm while our input is -80 dBm. 2. Dynamic Range The range. to a maximum input signal level that a component can accept and amplify without distortion.MODULE B RADAR HARDWARE 2.9 of dynamic range. which is at a level 3 dB above the amplifier's internally generated floor.3.5. At the figure-2. Dynamic Range = P1dB .
5. Typically. Figure 19: 1 dB Compression Point.0 / ALANYA 2005 24 .MODULE B RADAR HARDWARE 2. Pin graph. the 1 dB compression point refers to the output power (Pout) at that point.4. One dB (1 dB) Compression Point The 1 dB compression point is the point on a Pout vs. where an increase power input causes the measured gain to decrease from the linear gain by one dB. TURKEY RADAR TRAINING 1. if not explicitly stated.
Each offers advantages for specific applications within the performance domain of radio frequency (RF) systems (see Figure 21). modulators and RF circuits. Following figure 20 shows the general block diagram of a transmitter with klystron tube.0 / ALANYA 2005 25 . A lot of types of transmitters are available for radars depending on type of the radars and the applications. 3. TRANSMITTER General Overview Transmitter is one of the essential components of the radar system with a function of generating high power RF signal which will travel through the atmosphere and echoes of that signal will be received by the antenna after reflected by targets. two technologies (vacuum and solidstate electronics) are used to generate and amplify microwaves. voltage regulators. filters. high voltage power supplies and transformers. processors and control circuits. Within the frequency range of interest.1. Microwave power tubes (the principal product derived from RF vacuum electronics) are preferred for applications requiring both higher frequency and higher power. Figure 20: Simplified Transmitter Block Diagram. blowers.MODULE B RADAR HARDWARE 3. Electron transport in a vacuum conveys as advantages to microwave power tubes such TURKEY RADAR TRAINING 1. Transmitter unit of radar systems consists of microwave tubes (or solid state devices).
Classification and characteristics of microwave tubes are shown below: Figure 21: Microwave Tube Family.0 / ALANYA 2005 26 . and radiation hardness. and competitive efficiency and bandwidth at lower frequency and power. this in turn is governed by what frequency needs to be transmitted or whether the transmitter is to operate on a single spot frequency or be completely frequency agile. Alternatively. They require a lot of prime power and need a lot of cooling. They are used in radar transmitters to produce microwave energy of required wavelength and intensity. Though solid-state transmitters have become available. That is. TURKEY RADAR TRAINING 1. Figure 21 summarizes the various types of microwave power tubes in use today. Solid-state power amplifiers transmit/receive (T/R) modules.25 to 10 MW peak power) are the largest. they have not overtaken the age-old vacuum tube technology so far due to their limited power. solid-state power amplifiers combine the power from many transistors. The advantages of charge transport in a solid-state media yield compact devices with superior reliability. the frequency for each transmitted pulse deviates from the mean carrier frequency. and most costly portions of a radar system.MODULE B RADAR HARDWARE features as wide band performance. Conventional high-power-pulse radar transmitters (rated from 0. and active arrays use a variety of power combining techniques to provide competitive total power. currently with limited applications. Gyrotrons are newly emerging microwave power tubes. efficiency. The design of a transmitter is strongly affected by the type of RF transmitting source selected. Magnetrons. klystrons and travelling wave tubes still continue to be the main powerhouse of most radars. heaviest. thermal robustness.
MODULE B RADAR HARDWARE Figure 22: Typical Microwave Tube Characteristics and Applications. Figure 22 summarizes microwave power tube operating characteristics and applications. TURKEY RADAR TRAINING 1.0 / ALANYA 2005 27 .
in some of the less. as the electrons are released from the cathode. They are used extensively in commercial airliner weather and collision avoidance radar. They also are relatively inexpensive. including the ubiquitous microwave ovens. Whereas the latter tubes use a linear electron beam. Magnetrons are oscillators and usually operate in a pulsed mode. Randall and Boot were working on the development of radar for the British. Magnetron tubes are representative of an entirely different kind of tube than the klystron.expensive medical therapy equipment. Figure 23: Magnetron Tube. Magnetrons proved to be one of the most important developments of radar for World War II.0 / ALANYA 2005 28 . they are directed toward the anode.1. in almost all military and commercial navigation and weather radar systems. the magnetron directs its electron beam in a circular pattern by means of a strong magnetic field: In operation.2. 1996). However. 3. and in various industrial heating applications.MODULE B RADAR HARDWARE 3.2. Magnetrons can generate a lot of power in a small volume and are very efficient. since the electrons are influenced by the magnets in the resonant cavities. Their small size and high power output made them ideal for airborne use. Magnetron transmitters are now used at a variety of radar frequencies and can generate transmitted signals in excess of 500 kW. Transmitter Types Magnetron Tubes The magnetron tube for generating microwaves was invented by John Randall and Henry Boot in November 1939 (Buderi. they flow TURKEY RADAR TRAINING 1.
Figure 24: Klystron Tube.0 / ALANYA 2005 29 . One or more chambers contain collecting antennas that let the generated RF signal flow outside the tube. but at a much higher power level.2. This amplifies the signal. that cavity is excited at the same frequency as the input cavity. The energy distribution of the beam is altered as it travels through a resonant cavity. was invented at Stanford University in 1937 and originally used as the oscillator in radar receivers during World War II by two of the researchers instrumental. The klystron generally is referred to as a "linear beam" device because it utilizes a magnetic field in line with its electric field. the electrons "bunch" as the faster electrons overtakes the slower electrons. Output power can range from 10 kilowatts (continuous) to 10 megawatts (pulsed). Klystrons range in length from less than a foot to over 20 feet and operate with voltages ranging from a few hundred to several thousand.2. some accelerated). a pair of brothers named Sigurd and Russell Varian. These resonating chambers comprise the anode of the magnetron. The resonant cavity is excited by an input signal such that the beam is "velocity modulated" (some electrons are slowed. as a high power amplifier. TURKEY RADAR TRAINING 1. Farther down the tube. As the bunched electrons pass through another resonant cavity. 3. Klystron Tubes The klystron tube. .MODULE B RADAR HARDWARE circularly through the resonant chambers and set up an oscillation based upon their speed through the chambers.
The gain. The transmitter is designed solid-state based including the high-voltage modulator. The most common form of RF circuit used is a simple helix.MODULE B RADAR HARDWARE Amplification klystrons continue to find use in high-power (Radar). Transmitter. Unlike the klystron. 3. For example. therefore. but. the system capability for "Precise Weather Measurement' is absolutely superior to systems using any other type of transmitters. and power levels of TWTs are like those of the klystron. their values are usually slightly less than can be obtained with a klystron of comparable design.0 / ALANYA 2005 30 . Travelling Wave Tubes (TWTs) The TWT is an important member of the linear beam family of microwave power tubes. the interaction occurs continuously as an increasing travelling wave instead of discrete steps in cavities. The TWT's advantage is "bandwidth". in general. bandwidths of the order of 10 to 20 percent are more typical at the power levels required for long-range radar applications. Civilian agencies continue to use klystrons in many of their radar systems. the Federal Aviation Administration's Terminal Doppler Weather Radar uses a klystron amplifier because solid-state devices cannot generate the waveforms needed to detect severe weather and wind-shear conditions. TURKEY RADAR TRAINING 1.Performance of the full-coherent Klystron transmitter is extremely stable compared to a Magnetron transmitter. It is similar to the klystron in that a pencil beam of electrons is generated in an electron gun and kinetic energy is converted into RF energy as the beam interacts with an RF circuit. It can instantaneously amplify signals over a range of frequencies – several octaves. The radiation sound is kept ultra low level so that maintenance can be performed easily and friendly. efficiency. A wide bandwidth is necessary in applications where good range-resolution is required or where it is desired to avoid deliberate jamming or mutual interference with nearby radars. Although low power TWTs are capable of octave bandwidths.2.3. high-frequency radio transmitters and in scientific research applications.
) which determine its useful operating frequency and power output.generate very high.5. expensive. SSPAs are less expensive.power levels at millimetre wavelengths. not vacuum electronic devices.0 / ALANYA 2005 31 . Microwave power TURKEY RADAR TRAINING 1. and inherently quieter than microwave power tubes. Each type of transistor has specific limitations due to its material properties (defect densities. and employs very high voltages and high magnetic fields generated by superconducting solenoids. At lower frequencies and power. 3. thermal conductivity. a more recent development. Gyrotrons A gyrotron.2. more reliable. In transistors of a given material. The gyrotron promises important advances in fusion and because of the high resolution possible with its millimetre wavelengths. Performance depends upon the characteristics of the transistors used and the efficiency of the combining technique. carrier mobility. Solid-State Power Amplifiers Solid-state power amplifiers (SSPAs) use transistors. This prediction appears to be overstated. The assessments by some experts on that issue state that SSPAs soon will replace microwave power tubes in some applications.4. SSPAs for microwave applications are composed of many individual transistors connected in parallel.MODULE B RADAR HARDWARE Figure 25: Diagrammatic Representation of Travelling Wave Tube. It can do what no other microwave power tube can do -. It is large. heavy. their output "summed" in a combining network to achieve power levels useful for radar or telecommunications. looks like a linear beam device but performs like a combined linear beam and crossed-field device. 3. the output power generally varies inversely with the square of the operating frequency. to amplify microwaves. great improvements in radar imaging.2. etc.
That is. Therefore. The modulator applies a high voltage pulse through the pulse transformer to the klystron cathode. It charges a capacitor bank. particularly for mid. where microwave power tube devices are dominant. for mid.and higher. The solid state modulator represents the latest state-of-theart in high power solid state electronics. charging voltage stabilization. TURKEY RADAR TRAINING 1. it will have a storehouse of energy available for its use.and higher-frequency applications. This is mandatory for Doppler operation. (2) the main solid-state progress would be in improved efficiency and lower cost.0 / ALANYA 2005 32 . It is concluded that: (1) microwave solid-state amplifier capability would increase by a few decibels (dB) in the next decade. a capacitor bank and a pulse transformer. The purpose of the modulator is to switch the transmitter on and off and to provide the correct waveform for the transmitted pulse. it is usually controlled by another electronic device called the modulator. The Modulator generates high voltage pulse by switching high DC voltage from the HV REG. a solid-state switch assembly.3. and (3) the new solid-state devices being developed are not expected to improve power performance in the mid. The CCPS is basically a switch-mode power supply. the modulator tells the transmitter when to transmit and for what duration.MODULE B RADAR HARDWARE tubes continue to provide significantly higher power output and efficiencies than SSPAs. 3.and higher-frequency applications. The modulator also serves another function. Some researchers evaluated the current state of the technology and projected evolutionary improvements in the power output of well known microwave SSPAs.frequencies. It is designed to support the inherent high stability of a coherent radar. It stores up energy between transmitter pulses so when it is time for the transmitter to fire. The switching devices are solid state. the applications being served today by microwave tubes will likely continue without significant change. The voltage on the capacitor bank is controlled by means of a sensitive topping electronics resulting in a very high stability. The solid-state modulator comprises a capacitor charging power supply (CCPS). Modulator No matter what kind of transmitter is used in the radar.
Similar to the capacitor charging SMPS the solid state switch assembly is current limited. The pulse width control is provided by the transmitter control processor. TURKEY RADAR TRAINING 1. The selected switch modules provide sufficient margin in their critical parameters to guarantee trouble-free operation over the whole life time of the radar system. high power semiconductors are employed. Therefore if an arc occurs anywhere in the high voltage circuitry. Figure 27: Some Klystron Indicators.0 / ALANYA 2005 33 . Two different pulse durations are pre-programmed. As switches fast.MODULE B RADAR HARDWARE The high-power solid state switch assembly comprises the solid state switches as well as their trigger and protection circuitry. Figure 26: Front Panel of a TX Cabinet. an inherent protection is provided for the solid state switches. The solid state switch assembly is directly triggered from the radar signal processor. The pulse duration is set by a pulse termination trigger.
0 / ALANYA 2005 34 . Figure 29: Monitoring Points from TX.MODULE B RADAR HARDWARE Figure 28: High Voltage Section of aTX. TURKEY RADAR TRAINING 1. Figure 30: Klystron Tank.
Figure 33: Inside of an Air Isolated Tank.MODULE B RADAR HARDWARE Figure 31: A Klystron Tube.0 / ALANYA 2005 35 . TURKEY RADAR TRAINING 1. Figure 32: Modulator of a Transmitter.
Figure 35: Modulator of a Transmitter.MODULE B RADAR HARDWARE Figure 34: A Klystron Tube.0 / ALANYA 2005 36 . TURKEY RADAR TRAINING 1.
During transmission. The antenna performance determines the update rate of radar images. In general. according to the scanning strategy decided by the user. Because a radar antenna may both transmit and receive signals.so to speak . the duplexer determines whether the antenna is connected to the receiver or the transmitter.0 / ALANYA 2005 37 . The receiver determines whether the signal should be reported and often does further analysis before sending the results to the display. ANTENNA General Overview A radar antenna (the British call it aerial) may be thought of as a coupling device between free space propagation and the waveguide from the transmitter. The antenna gathers the weak returning radar signals and converts them into an electric current. On reception. the antenna features the highest acceleration rates and the best step response times available on the market. and the antenna causes the energy to radiate into free space. The display conveys the results to the human operator through a visual display or an audible signal. energy from the transmitter is switched to the antenna by the duplexer. where it is delivered to the receiver. The antenna collimates the microwave energy into a narrow beam while sending it out. the coupling to free space during transmission is identical with the coupling to the transmission line during reception. These two roles were expressed by the transmitting gain and the effective receiving aperture alias receiving gain. it is expected radar antennas to have the following properties: TURKEY RADAR TRAINING 1. The main function of the antenna is to shape the transmitted beam so that the radiated energy is concentrated in the desired direction in space. In order to support the most advanced scan strategies. The antenna is . The larger the size of the antenna.MODULE B RADAR HARDWARE 4. It is also capable of changing its elevation by rotating about a horizontal axis so that probing of the hemispherical volume of the atmosphere with radar as the centre is possible. By reciprocity. 4.the 'eye' of the radar. the better the angular resolution. A radar receiver detects and often analyzes the faint echoes produced when radar waves bounce off of distant objects and return to the radar system. The antenna generally rotates about a vertical axis scanning the atmosphere in azimuth.1. a signal in free space impinges on the antenna and is coupled to the transmission line that is connected to the duplexer.
Such antennas date back to the turn of this century. the technology is advanced.so that the antenna can transmit and receive a radar pulse without distortion and pass all operating frequencies within the allocated frequency band • The beam must be scanned Figure 36: Pedestal and Antenna. 4.1. 4. Antenna Types There are three major types of antenna used in radar applications.0 / ALANYA 2005 38 .MODULE B RADAR HARDWARE • • • • High forward gain or directive gain Narrow beamwidth Low sidelobe level Broad-banding . parabolic reflector antennas and offset feed antennas. Phased Array Antenna Early radar systems used antenna arrays formed by the combination of individual radiators. These are phased array antennas. TURKEY RADAR TRAINING 1.2.2. Better components and not least the advent of computers led to designing well matched apertures. Those types of antennas will be explained briefly. after a long pause. Today.
TURKEY RADAR TRAINING 1. Most of the antennas used in weather radar applications are parabolic reflectors. each element being individually controlled in phase and amplitude. 4. then none of the radiated beam is blocked by the feed antenna and support structure. such as slots or dipoles.0 / ALANYA 2005 39 . For small dishes. teed blockage in an axial-feed dish causes a significant loss in efficiency. Thus. 4.2.MODULE B RADAR HARDWARE The phased array antenna has usually a planar aperture that is assembled from a great many similar radiating elements. Figure 37: Parabolic Dish Antenna. we might expect an offset-feed dish to have higher efficiency than a conventional dish of the same aperture.2. Phased arrays allow scanning the beam electronically to a certain degree which makes the mechanical movement of antennas unnecessary. only a small bit at the edge of the beam is blocked. Otherwise. Accurately predictable radiation patterns and beam pointing directions can be achieved. These types of antennas give a narrow beam which increases performance of weather radars significantly. If the section does not include the centre of the dish.2. Parabolic reflectors Parabolic reflectors emit all radiation at focus emerges in a beam parallel to the axis. Offset Feed Reflectors An offset-feed dish antenna has a reflector which is a section of a normal parabolic reflector as shown in Figure 37 and 38. Parabolic reflectors are suitable mainly at microwave frequencies because it must be large compared with the wavelength.3.
3. because every antenna exhibits some directive properties.0 / ALANYA 2005 40 . and thus the gain or directivity of a given antenna is expressed as the increase in power radiated in a given TURKEY RADAR TRAINING 1. Figure 39: An Offset Feed Antenna. the isotropic antenna is a convenient reference point.MODULE B RADAR HARDWARE Figure 38: Geometry of Offset Parabolic Dish Antenna. 4. However.3. There is no such antenna. sometimes called a spherical radiator.1. 4. Basic Characteristics of Antenna Antenna Gain An antenna which equally radiates in all directions is called an isotropic radiator or source.
assuming the same total power in both cases accepted by the antenna. The ratio of the two is called the efficiency of illumination. G= 4πAg λ2 All points on the antenna do not couple uniformly to the transmission line.0 / ALANYA 2005 41 . The relationship between the gain and the beamwidth of an antenna depends on the distribution of current across the aperture.MODULE B RADAR HARDWARE direction compared to the power radiated by the fictitious isotropic antenna. For a reflector antenna the following expression is sometimes used: G = 20000 θBØB Where θ and Ø are the half-power beam widths. measured in the two principal planes. so that the amount of energy reaching the receiver is reduced. Thus G= Power gain= Maximum field strength radiated from given antenna Field strength radiated from reference antenna The gain is a ratio.e. in degrees. This is a rough rule of thumb that can be used when no other information is available. i. when uniformly coupled to the transmission line. Thus a transmitting antenna with a gain of 30 dB would radiate a signal in the direction in which the signal is maximum 30 dB greater than a signal from an isotropic or reference source which is fed with the same transmitter. The effective area of the antenna is therefore the area of cross section which. delivers the same energy as the actual antenna. and is expressed as K=Ae/A . where A is the physical area. It may be regarded as a measure of the effective area presented by the antenna to the incident wave. a number that is usually converted into dB. Direct measurements of the antenna gain can seldom be made and a gain figure is usually obtained by knowing the effective receiving aperture of the antenna or effective area Ae. TURKEY RADAR TRAINING 1.
Radiated power is focused into the pencil beam. Side lobes are a direct result of diffraction occurring near the edges of a radar antenna. Another benefit of the bigger antenna is narrower beam width which is quite important performance especially for such as the system used in airports. Figure 40: Antenna Size and Pattern (AZ Angle). this "Precise Weather Measurement" is one of the most important functions required to the modern Doppler Weather Radar.3. Beam width of parabolic reflector at half power point is simply given by 70λ θ= D Where θ is the beam width.0 / ALANYA 2005 42 . which surround the main beam (primary lobe) like haloes Side lobes extend outward only a short distance from the radar and contain very low power densities. Since accurate weather information should be correctly delivered to the various users responsible for weather alert management. so that the echoes have more precise information to be detected. λ is the wave length and D is the diameter of the antenna. antennas produce rays of energy called side lobes.MODULE B RADAR HARDWARE but should not be a substitute for more exact expressions that account for the actual aperture illumination 4. In addition to the main beam. TURKEY RADAR TRAINING 1. Antenna Pattern Larger diameter antenna provides more antenna gain which directly affects to the system sensitivity.2.
to concentrate the energy of radio frequency signals scattered due to rainfall particles etc. The microwave circuit is composed of a parabolic reflector and a feed horn which feeds the electromagnetic wave to the parabolic reflector. Drive motor rotates the Antenna on both azimuth (AZ) and elevation (EL). The electric circuit is comprised of drive motors.MODULE B RADAR HARDWARE However. Resolvers detect rotation angle on AZ and EL as an angle detector. Figure 41: Main Beam and Sidelobes. which enable to transfer the radio frequency energy both ways between fixed waveguides and rotating Antenna. The Antenna also includes rotary joints. The function of the microwave circuit is to radiate electromagnetic pulse wave from the Transmitter. This leads to confusion in interpreting close targets because side lobe targets are displayed along with the main beam targets. resolvers and slip ring etc.0 / ALANYA 2005 43 . and to transfer them to the Receiver via drive mechanisms. TURKEY RADAR TRAINING 1. Main Parts of a Radar Antenna Antenna consists of microwave circuit. even though they are weak.4. electric circuit and mechanical system. Slip ring supplies power for AZ and EL axis motor between rotation part and fixed part. 4. side lobes can detect strong non-meteorological targets near the radar and are also disturbed by nearby ground reflections.
0 / ALANYA 2005 44 . Resolver forms servo loop system together with other components for accurate control of rotation speed and positioning of the Antenna. Electric circuit controls rotation and positioning of the Antenna in azimuth and elevation. 4. The pedestal carries the reflector and other equipment. which form the antenna.MODULE B RADAR HARDWARE It also transfers angle data from servo loop system. Figure 42: Diagram of the Antenna.4.1. Mechanical system is structured by driving power transmission system to rotate the Antenna. with a capability of continuous rotation in azimuth and elevation scanning continuously during whole operation period. Pedestal and Reflector The reflector generally consists of a partitioned solid surface dish with a stiffening back structure. TURKEY RADAR TRAINING 1.
MODULE B RADAR HARDWARE Figure 43: Pedestal and Reflector 4.4. coaxial line (upper part) on the output side and the one (lower part) on the input side are electrically joined by means of a choke coupling. the upper part can rotate while the lower part is fixed.1-2(a).2.0 / ALANYA 2005 45 . As illustrated in Fig . Therefore. Rotary Joint Two rotary joints (one each for AZ and EL) are located in the waveguide near the Antenna. TURKEY RADAR TRAINING 1. Rotary joint performs the role to relay between fixed waveguide and the Antenna which rotates and turns both on AZ and EL.
MODULE B RADAR HARDWARE Figure 44: Rotary Joint. TURKEY RADAR TRAINING 1. Both the ring part and the brush are divided for signal and for electric power. and the appearances are different. Slipring The Slip ring sends power and signals to the EL drive mechanism when a ring part on AZ rotation side and a brush installed in a brush holder on the fixed side slide.4.0 / ALANYA 2005 46 . 4.3. The brushes are installed double in order to prevent the generation of electric arc. Figure 45: Some Sliprings.
Waveguides also have some use at optical frequencies.4. where they are formed into pencil beam usually less than 1 degree beam width and radiated into free space. symmetrical cross section beam width is realized.MODULE B RADAR HARDWARE 4. Figure 46: Rotary Joint and Waveguide. typically take the form of rectangular hollow metal tubes but have also been built into integrated circuits. A waveguide of a given dimension will not propagate electromagnetic waves lower than a certain frequency (the cut-off frequency). Each of these arrangements is known as a mode of propagation. Generally speaking. Electromagnetic waves are radiated from Feed horn. TURKEY RADAR TRAINING 1. which is the main mode of a rectangular waveguide.4. is applied to the pyramidal horn and also because of optimization of the aperture. The pyramidal horn is adopted to feed the parabolic reflector with electromagnetic wave. Waveguides.0 / ALANYA 2005 47 . Since TE10 mode. the electric and magnetic fields of an electromagnetic wave have a number of possible arrangements when the wave is travelling through a waveguide. Waveguide and Feed Horn Waveguide is a transmission device that controls the propagation of an electromagnetic wave so that the wave is forced to follow a path defined by the physical structure of the guide. They are sprayed to the parabolic reflector. which are useful chiefly at microwave frequencies in such applications as connecting the output amplifier of radar set to its antenna. The interface between feed horn and waveguide is shielded with a pressure window in order to prevent leakage of pressurized air within waveguide.
In some cases.0 / ALANYA 2005 48 . This component is a very fast switching magnetic type. It is used together with a single receiver/transmitter to connect an antenna with horizontal and vertical waveguide feed. which separates the transmitted and received pulses. The technical principle of this magnetic switch is similar to the circulator. That makes it possible to switch between two normal pulses with a PRF up to 1200Hz.5. Mechanical switches are much slower than this magnetic type. some Doppler weather radars have been developed as Polarimetric System with a capability of detecting the Differential Reflectivity ZDR.4. a dual polarization switch unit is used to make switching between the waveguides for vertically and horizontally polarized waves. TURKEY RADAR TRAINING 1. Figure 47: General Block Diagram of Dual Polarization System with Dual Polarization Switch. so that the transmitter must not generate any pulses during the switching time of a mechanical switch. The dual polarization switch is a special kind of waveguide component.MODULE B RADAR HARDWARE 4. Also the dual polarization switch works as a four port circulator. Dual Polarization Units (in Polarimetric Radars) Recently. This is very important for the understanding of the operation of the whole system.
Figure 48: Dual Polarization Switch.
This kind of circulator has the opportunity to change the direction of the circulation by electrical driven magnets. To change the direction of the circulation does not mean to switch like a normal mechanical switch If direction A was chosen, the electromagnetic waves travel from port 1 to port 2, from port 2 to port 3, from port 3 to port 4 and from port 4 to port 1. If direction B was chosen, the waves travel in the other way : from port 1 to port 4, from port 4 to port 3, from port 3 to port 2 and from port 2 to port 1. Port 3 is terminated with a dummy load due to the reason that normally not all ports are needed.
Figure 49: Dual Polarization Switch. However, the most preferred method in Polarimetric Radar Systems is to divide transmitted power and send to antenna via two separate circulator and collecting received signal by two identical receivers. Signals sent are half powered for each channel here, but radiated simultaneously in contrast to Dual Polarization Switched Type. This allows user to get different Polarimetric Radar Products.
Figure 50: General Block Diagram of Dual Polarization System without Polarization Switch.
Antenna Control Unit Antenna control unit (ACU) performs all functions regarding positioning, scanning, checking and safety control of antenna. It also generates BITE information and send to the radar control processor. ACU reports the actual angle of the antenna dynamically to external devices. Resolver system, as an angle detector, is being used for AZ and EL axis, independently. ACU has another function for safety control that, for example, the servo power commanded from external Servo Processor is cut when any interlock system is activated. This safety control is made with the status signals of ACU itself and those reported from ANT. Servo Motors It is generally required for an antenna used in a Weather Radar System to be capable of scanning its narrow pencil beam in any direction, and reporting accurate position to where the Antenna is facing. So, Servo Motor-Driver system is preferred in both Azimuth and Elevation scanning control.
The constant speed control system of a Servo Motor is a mechanism that monitors any variations in the motor's speed so that it can quickly and automatically return the speed to its correct value. TURKEY RADAR TRAINING 1.MODULE B RADAR HARDWARE Servomechanism is an automatic device for the control of a large power output by means of small power input or for maintaining correct operating conditions in a mechanism. Angle Detector Angle detector. Angle detector forms servo loop system together with other components for accurate control of rotation speed and positioning of the Antenna. Angle detector forms servo loop system together with other components for accurate control of rotation speed and positioning of the Antenna. It is a type of feedback control system. detects rotation angle on AZ and EL.0 / ALANYA 2005 52 . resolver system.
0 / ALANYA 2005 53 .MODULE B RADAR HARDWARE TURKEY RADAR TRAINING 1.
. Cable. Servo Amp. Waveguide and its Tray. TURKEY RADAR TRAINING 1. Controller. 7m Parabolic Antenna.0 / ALANYA 2005 54 . TX Cabinet. Position Resolver of Antenna. Angle Detector.. Antenna Control PCBs. Obstruction Lights. Antenna Pedestal. Servo Motor.MODULE B RADAR HARDWARE Figure 52: Some Pictures on Dehydrator. Antenna Control Unit and Servo Amp.
the heaters do not interfere physically or electrically with the AC of the radio transmission. RADOME General Overview Antennas of ground based radars are often subject to severe weather. and the fact that radomes may be unsightly if near the ground. where it can cause overheating. however. In the case of a spinning radar dish antenna. A radome does however add to the wind load and the ice load. A radome (radar dome) is a weatherproof enclosure used to protect an antenna. the beam width.MODULE B RADAR HARDWARE 5. It is used mainly to prevent ice (especially freezing rain) from accumulating directly onto the metal surface of the antenna. and so must be planned for when considering overall structural load. heaters are often used instead. A radome prevents this by covering the antenna's exposed parts with a sturdy. causing VSWR (Voltage Standing Wave Ratio) to rise as well. reducing its range. the polarisation. side lobe level. A properly designed radome should distort the antenna pattern as little as possible. For stationary antennas. and the direction of the bore sight. which keeps the ice far enough away from the antenna to prevent any serious issues. typically fibreglass. weatherproof material.1. the radome also protects from debris and rotational irregularities due to wind. it causes the station's output power to drop dramatically. 5. the following radome characteristics are specified: TURKEY RADAR TRAINING 1. This reflected power goes back to the transmitter. So some enclosure is needed for antennas to survive and to perform under adverse weather conditions. For this reason. in addition to its own weight. In order to keep the affects as low as possible. A fold back circuit activates to prevent this. The presence of a radome can affect the gain.0 / ALANYA 2005 55 . excessive amounts of ice can de-tune the antenna to the point where its impedance at the input frequency rises drastically. as well as change the VSWR (voltage-standing-wave ratio) and the antenna noise temperature. These enclosures are called as RADOME. Radomes must be mechanically strong if they are to provide the necessary protection and they must not more interfere with the normal operation of the antenna as absolutely necessary. Usually running on DC.
Orange Peel: The radome is subdivided into relatively large vertical pieces with mostly vertical joints. These parameters have a close relation to the antenna that is covered. thus the radome performance can only be estimated on the basis of the antenna characteristics. Radome Types Due to its size the radome has to be subdivided into panels for production and transportation reasons. The latter ones use different types of sandwich panels. Quasi Random Orange Peel Figure 53: Different Types of Radome. Their properties may be adjusted to the antenna and local environment. Out of an infinite number of possible solutions most of them can be assigned to one the following types: Igloo : The radome is subdivided into small regular pieces with either vertical or horizontal joints. Igloo TURKEY RADAR TRAINING 1. Quasi-Random: The radome is subdivided into a number of irregular pieces without preferred joint direction.0 / ALANYA 2005 56 . There are several radome types available as far as the supporting structure and the wall material is concerned.2. 5.MODULE B RADAR HARDWARE • • • • • • One way transmission loss for the dry and wet state Increase of side lobe level Reflected power Cross polarisation degradation Bore sight error Beam width increase. There are foam radomes and space-frame radomes.
Modern radars use computer displays for displaying their products. mean velocity and spectrum width.2. In particular the Built-in Test Equipment (BITE) is controlled by this processor. attenuation and partial beam filling).1. 6. They are generally known as control and signal processors. control of the function of each sub-unit and signal processing are done by dedicated computers incorporated within the system. constant altitude PPI (CAPPI). Plan position indicator (PPI). TURKEY RADAR TRAINING 1. Additionally the control processor interfaces the radar system to the data processing system. Earlier radars used dedicated cathode ray tubes to display the echoes.MODULE B RADAR HARDWARE 6. are a few to mention. Many commercially available off-the-shelf digital signal processors (DSPs) may be linked together to meet the computational requirement. range height indicator (RHI) amplitude range scope (AR scope). quality assurance and applying various corrections to the dataset in addition to performing complex statistical signal-processing jobs. 6. Radar displays are of different types. Control Processors The radar control processor is responsible for the control and supervision of the radar system. RADAR CONTROL AND SIGNAL PROCESSORS General Overview In modern radars. The states of a large number of subsystem parameters are monitored and if a fault is detected the control processor acts according to the severity. described later in the article. The signal processor computes the reflectivity (with and without corrections for clutter. The signal processor unit performs analogue to digital conversion. second trip echo.0 / ALANYA 2005 57 .
The resulting power estimate is corrected for system noise (by subtracting the average system noise level). and optionally for transmitter power. Figure 54: Signal Processor Card. Signal Processor The signal processor is a critical unit of radar system with important functions. The LOG receiver input is only used for an intensity estimation which is used to drive an attenuator which prevents a saturation of the linear channels. intensity estimation consists simply of integrating the power in the linear channel (power = I2 + Q2) over range and azimuth. Since the signal to be processed by signal processor is a complex linear signal. Signal processor accepts analogue linear channel I and Q as well as a LOG receiver input. It performs three main tasks: (1) Triggering of the radar system. as specified by the user.MODULE B RADAR HARDWARE 6. polar coordinate tagging and pre-processing of the received signals. (2) Phase and frequency modulation of the carrier signal and (3) Digitizing.3.0 / ALANYA 2005 58 . especially of the transmitter. for target range (using an R-squared relationship). TURKEY RADAR TRAINING 1. for atmospheric attenuation (using an attenuation factor supplied by the user).
MODULE B RADAR HARDWARE Figure 55: Signal Processor Card. Figure 56: Digitizer. TURKEY RADAR TRAINING 1.0 / ALANYA 2005 59 .
MODULE B RADAR HARDWARE Figure 57: A Radar Control Processor.0 / ALANYA 2005 60 . TURKEY RADAR TRAINING 1.
MODULE B RADAR HARDWARE Some View of Radar Systems: Figure 58: Balıkesir Radar Site-Turkey. Figure 59: Hardware of Zonguldak Radar/Turkey.0 / ALANYA 2005 61 . TURKEY RADAR TRAINING 1.
Figure 61: General View of Radar Hardware.MODULE B RADAR HARDWARE Figure 60: Scenic View of Ankara Radar/Turkey. TURKEY RADAR TRAINING 1.0 / ALANYA 2005 62 .
MODULE B RADAR HARDWARE 7. Merill I. 10. 10 August 2003A. Jeffrey Keeler January. 17. S. TSMS.K. 13.S. Ronald E. 20. FMI Data Quality Improvements on AP Mitigation.2005 Radar Basics. Rajesh Rao. Jeff Haby Doppler Radar. Doppler Weather Radar System. Oguzhan Sireci. 2001 Doppler Weather Radar System. 4. BoM. Kalyanasundorom. National Weather Service. 2.A Radar Training Information.A. TSMS. 2002 Radome Influence on Weather Radar Systems.TECO 2005. S.0 / ALANYA 2005 . 19. U. 18. Range Velocity Mitigation. Suresh and J. Skolnik Doppler Radar and Weather Observations. Department of Defense.Meteor 1000CUser Manuel and DocumentationGematronik GmbH.Mitsubishi Electric Corp.2004 Technical Description TDR Series-C Band Doppler Radar. P. NOAA Detection of ZDR abnormalities on operational polarimetric radar in Turkish weather radar network. 2005 63 TURKEY RADAR TRAINING 1. 23. 12. 12. 16. April 1997 Weather Watch Radar.S. Enterprise Electric Corp. 9. David K.P.May. Thampi. TSMS. Firat Bestepe.May. Australia. 1. 25. Industrial Assessment of the Microwave Power Tube Industry.March .J.July. WMO. Cheng. R. 5. 3. Renato Croci Feasibility Report for Turkey Radar Network. REFERENCES: Radar for Meteorologists. A detecting tool and measuring instrument in meteorology Current Science. Vol. 21. Bhatnagar. Principle and Calibration Issues Gematronik GmbH Alexander Manz Principles of Radar.B. and Zrnic D.2001 RC-57A Weather Radar Training Document and User Manuel. 6. Introduction to Radar System. BoM. 3.S. Radtec Engineering Radar Range Folding and The Doppler Dilemma. Australia Radar Meteorology Doppler. Doviak R.2000 Weather Radar Principles. Heikki Pohjoa.Wolfgang Manz 12. R.2005 Modernization of Observation Network in Turkey. 4th.1983 Weather Radar Calibration. 24. 8. TECO 2005.1999 Radar Meteorology. Rinehart August 1997 Radar Handbook. 7. 14. 22. U. 11. No.Jürg Joss July. Merrill I. Ercan Buyukbas. 4th. 85.Gupta 15. Skolnik Field and Wave Electromagnetics.
Ercan Büyükbas. Cihan Gozubuyuk. 28. M.Sep. 27. Aytac Hazer. Mustafa Kocaman.2004 Radar Basics. 29. Hardware Maintenance of Weather Radars. 34. Training Notes. Aytac Hazer.0 / ALANYA 2005 64 . Abdurrahman Macit. 2002 30.1997 32. 31. Distance Learning Operations Course. Instructional Component 5. Weather Radar Maintenance Procedures and Measurements. TSMS.NOAA Turkish Radar Network.3. Serkan Eminoglu. 23. Radar Training Information.Kemal Aydin. 33. Ver: 0307 Notes on Radar Basics. Oguzhan Sireci. 2005 Operational Use of Radar for Precipitation Measurements in Switzerland Jürg Joss(1)Bruno Schädler(2) Gianmario Galli(1) Remo Cavalli(1) Marco Boscacci(1) Edi Held(1) Guido Della runa(1) Giovanni Kappenberger(1) Vladislav Nespor(3) Roman Spiess(3) Locarno.MODULE B RADAR HARDWARE 26. Ismail Temir. TSMS. reports and guidelines published by WMO Technical Brochures of Radar Manufacturers TURKEY RADAR TRAINING 1. Principles of Meteorological Doppler Radar. Radar Lecture Notes and Articles available in internet Booklets. Cihan Gozubuyuk.


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"Built to Sell" by John Warrillow has been highly recommended by my friend, after reading this book, I would do the same to introduce and recommend to all my friends. No matter you're actively trying to sell your business, or having a dream to start your own business.
Certainly as a business owner, you don't want your business all depends on you, you want your company can run with their founder, can be scaled and grown.
This book is using a fictional story to illustrate the author's tips and points. I have learned a great deal of knowledge from the book. In order for myself to remember I have write this summary and notes about this book. Hope it can be useful to you as well, whenever you need to find a reference or forget some of the points on the book, you can find the information from here.
How to create a business that can thrive without you?
Before you start this process, engage a good accountant experienced in helping business owners with succession planning. Don't wait until have an offer to see an accountant.
Isolate a product or service with the potential to scale.
Once you've isolated what is teachable, what your customers value, and what they need most often, document your process for delivering this type of product and service.
Next, name your scalable product or service. Name your offering, along with each of the steps you take to deliver it, to differentiate your offer so that you can set its price and payment terms.
Revamp all of your customer communications to describe your process in a uniform way.
Create a positive cash flow cycle.
To create a positive cash flow cycle, charge your customer in full or in part for your product or service before you pay the costs of whatever it is you provide.
the second most important number on the page may be the working capital calculation. If your offer does not include details on the working capital calculation, be sure to lock that number down before you agree on anything.
Your job as an entrepreneur is to hire salespeople to sell your products and services so you can spend your time selling your company. As you build your sales team, look for people enjoy selling, and like the product. Avoid hiring salespeople who come from professional services companies.
Visit www.builttosell.com to find a template for a long-term incentive plan.
If your company has less than $2 million in sales, a business broker will best serve you. If it has more than $2 million in sales, a boutique mergers and acquisitions firm is probably you best bet.
Your broker needs to recognize that you have created something special and deserve to be compensated at a higher rate.
Think about it from their perspective and make sure there is something in it for them if the deal goes through.
Own the annual awards program for your category: Ernst & Young created the entrepreneur of the year awards program.
Own the event for your industry.
An earned-out is used by an acquirer to minimize his or her risk in buying your company.
During due diligence period, a professional buyer will dispatch a team of MBA-types to your office who will quickly identify the week spots in your model.
Trick #2: Checking to see if your business is vision impaired.
Trick #3: Asking your customers why they do business with you.
Don't generalize; specialize. If you focus on doing one thing well and hire specialists in that area,the quality of your work will improve and you will stand out among your competitors.
Relaying too heavily on one client is risky and will turn off potential buyers. Make sure that no one client makes up more than 15 percent of your revenue.
Owning a process makes it easier to pitch and puts you in control. Be clear about what you're selling, and potential customers will be more likely to buy your product.
Two sales reps are always better than one. Often competitive types, sales rep will try to outdo each other. And having two on staff will prove to a buyer that you have a scalable sales model, not just one good sales rep.
Ignore your profit-and-loss statement in the year you make the switch to a standardized offering even if it means you and your employees will have to forgo a bonus that year. As long as your cash flow remains consistent and strong. You'll be back in the black in no time.
Build a management team and offer them a long term incentive plan that rewards their personal performance and loyalty.
If you want to be a sellable, product-oriented business, you need to use the language of one. Change words like "client" to "customers" and "firm" to "business". Rid your web site and customer-facing communications of any references that reveal you used to be a generic service business.
Don't issue stock options to retain key employees after an acquisition. Instead, use a simple stay bonus that offers the members of your management team a cash reward if you sell your company. Pay the reward in two or more installments only to those who stay so that you ensure you key staff stays on through the transition.
Below the links are from the books as well, I jogged down the links for the future reference.


Aluminium Shapes was established in the 1980's as an alternative in an extrusions market dominated by large inflexible companies.
Aluminium Shapes was established in the mid 1980's. Its' founder, Nigel Fuller, had identified that the aluminium extrusions industry was dominated by large companies that were inflexible in terms of lead times, batch sizes and capability.
'Ali Shapes' filled a gap in the market by looking to deliver what many customers wanted, when they wanted it. In the early 90's, the mass market was Georgian Bar.
This is the tiny aluminium section you see in double glazed units and in carpet trim. It was a huge market back then but changed with the popularity of wooden flooring.
In the noughties, we focused on the domestic appliances market, predominantly cooker doors (Stoves and Glen Dimplex). This is still an important market for us.
Now one of our big priorities is the air diffusion market. Our ability to produce high volume thin sections for heating and ventilating has seen us corner a significant part of the building sector, along with lighting.
Sector and application neutral, we've always been passionate about helping customers make the aluminium impossible, possible.
So whether it was working in the booming industry of carpet trim through to working in the supply for major uses like Tesco, Bentley and Apple, the team at Ali Shapes remains fully committed to deliver our unique brand of flexibility to the extrusions market.
Thirty years since inception, our multi-press operation in Corby combined with our unique ability to problem solve provides for those must-deliver short lead times; for sections and batch sizes that our customer demand.
We believe that this ethos sets us apart in our industry. We have both direct and indirect presses plus an extensive range of fabrication.
Our customer first attitude that flows through all levels and departments will help us secure our place at the forefront of a demanding market as we continue to work with customers, new and old and challenge the traditional 'rules of extrusion'.


Just purchased a new GTI from Executive VW. Paul and Garret did a great job of making sure everything went smooth. If your in the market for a new VW head directly to executive VW.
Choosing Executive Volkswagen to purchase my first car was the best decision I could have made. When I walked in the door I was immediately greeted by Bill a very professional and friendly salesman. Bill was very down to earth, compassionate and had my best of interest in my purchasing a car that was both reliable and suited my lifestyle. He was very patient and took his time with me answering any questions I had about the Tiguans. He did not rush the process at all with me and he made buying my first car very fun and completely stress free. He was especially patient with my five year old daughter and allowed her to explore the Tiguans and be a part of the process with me. Bill was an amazing salesman and really wanted me to find a car that I fell in love with and that I felt completely comfortable with and that is exactly what he accomplished. It was very clear that he took his profession seriously and wanted me to be 100% satisfied with my purchase. I would hands down recommend Bill as a salesman to anyone looking for their new car. Garret the finance manager and Scott the manager were also wonderful to work with and made the process very simple and stress free. I am so happy with my purchase of my Tiguan and that I chose to purchase my first car from Bill at Executive Volkswagen!
Looking for a new car can be a long and stressful process but this dealership made it quite the opposite. Upon arrival we were quickly greeted by Billy who was very knowledgable and friendly. He was able to answer all of my questions about differences between the models of WV Tiguans I was looking at. Unlike other dealerships I have visited, I did not feel pressured into anything. Instead, I felt as though Billy really cared about what I wanted and tried to accommodate all of the things on my wish list. After finding the perfect car, Garett worked with the finance portion of our purchase and was very friendly, quick and efficient as well - he even helped us get a great deal on out insurance for our vehicle. Within three hours I found the perfect car with an amazing sales person, got the vehicle registered and was able to go home with the car that day which was only possible because the Billy and Garret stayed after hours to complete this process. After working in customer service myself, It is very clear when employees are really there to make the customer happy and do everything in their power to do so. Executive Volkswagen of North Haven is a prime examples of this. I would highly recommend this location because of the wide variety of vehicles they have on the lot and the amazing staff, especially Billy!
By far the simplest and easiest car purchase I have ever made. Garrett and Will made it super easy for my wife and I to get a great price on a GTI and get in and out of the dealership. Thank you so much!
I had a great experience with Executive Volkswagen from start to finish. Everyone I encountered was friendly and helpful and made sure I felt taken care of. Will did a wonderful job introducing me to my Mazda CX-5 - I never felt like I was being sold a car, but rather he answered all of my questions and concerns genuinely and I felt heard and comfortable. I had all the information in front of me with no hidden info or fees when I made my decision to buy. Very confident and stress-free shopping and buying experience. Even the day of pick up went smoothly and finance and registration paperwork were a total breeze. Amazing. I love my new car. Thank you!!
I recently bought a used Eos from Executive VW. Scott was patient answering all my questions through email. Once I arrived at Executive my salesman Chris was a joy to work with. He was very patient and kind! The whole buying process was made super easy. I love my new car! Can't wait to put the top down! Thank you!
Exceptional service from the Salesman David to the Finance Manager Garrett..Top notch team from the test drive to delivery.


Since Donald Trump has just released his plan to completely dismantle and destroy our federal government, I hope this all works out the way Tom Arnold is saying. What kind of reality are we in where the fate of our country is hanging on Tom f*cking Arnold?!
Comedian Tom Arnold said Friday that he and President Trump's former longtime personal lawyer are teaming up to "take down" the president.
Any old port in a storm.
I wouldn't count on this … see the interviews on CNN and The Last Word.


Before we get the party started, a little foodie treat. Remember when I made the Christmas pudding vodka, I had all that boozy fruit left over? Well, Malcolm turned it into a sort of strudel, using filo pastry - delicious!
there were lots more that I didn't manage to get photos of - lots and lots of super work! The evening ended with a lovely supper laid on by the committee, but I was too busy blethering (and eating) to take a photo!
and I had a coronation chicken wrap - delicious!


Soil RequirementTolerant of many soil types and can thrive in heavy clay.
Unique CharactersticsThe drought-tolerant flower will rise in an open spike of star-shaped blossoms. The pale blue to deep blue flowers will grace your garden! Suitable for xeriscaping!


text:
Police 'fed up' with Kearns gang dispute that led to deaths of 2 bystanders
Engaged couple was hit and killed by truck fleeing shootout, officers say
By Pat Reavy @DNewsCrimeTeam
Published: September 20, 2017 11:50 am
Pace family
Lloyd Everett Pace, 55, and Tami Lynn Woodard, 50, both of Kearns, were killed Tuesday, Sept. 19, 2017, when their vehicle was hit by a pickup truck trying to flee the scene of a drive-by shooting, police say. The couple was engaged to be married.
2 dead, 2 injured in Kearns shooting, car crash
KEARNS — Police say an ongoing dispute between two rival gangs has "ramped up" over the past month, and seemingly came to a head this week, resulting in the deaths of two innocent bystanders Tuesday night.
"This is getting absolutely ridiculous," Unified Police Lt. Brian Lohrke said. "I know the citizens in Kearns are absolutely fed up with it. We're fed up with it. We're going to be ramping up our efforts on the gang end. We're absolutely furious about this."
Tami Lynn Woodard, 50, and Lloyd Everett Pace, 55, both of Kearns, were in a Toyota Yaris about 7:30 p.m. Tuesday when they were hit by a Ford F-150 pickup truck with four gang members inside who were trying to flee the scene of a drive-by shooting, Lohrke said.
Woodward and Pace were pronounced dead at the scene. The couple had been engaged since December, according to their Facebook pages.
Investigators believe the truck that smashed into the couple was involved in at least three other shooting incidents on Monday, Lohrke said. Detectives had already been looking for it when the crash was reported.
"We believe this truck was also involved in some shootings in Kearns the night before in this same area, but no one was injured," he said.
In those cases, the occupants of the vehicle were either the aggressors and committed drive-by shootings, or were the targets of retaliation by a rival group, Lohrke said.
The drive-by shootings on Monday are also connected to the shooting of a 17-year-old boy on Sunday near 6200 S. Loder Drive (5155 West), he said.
Another drive-by shooting with no injuries was also reported in Kearns on Sept. 9.
Whether the shootings can also be connected to the killing of 16-year-old Fernando Aranda, of Kearns, was being investigated Wednesday. Fernando was shot and killed May 30 near 4700 W. Thayn Drive (3935 South) following an argument between two groups. That shooting came four hours after a 15-year-old boy was shot in the abdomen at 3810 S. Redwood Road. The boy survived his injuries, according to police.
Tuesday night, the pickup truck drove past a known gang house on the corner of 5240 West and 5400 South about 7:30 p.m., Lohrke said. Witnesses told police that a shootout ensued with both occupants of the vehicle firing at the house and one or more people from inside the house firing back.
As the truck was trying to speed away from the house, it crashed into the Yaris just a short distance away, causing the Yaris to crash into a driveway and the pickup truck to flip over.
When officers arrived, a 19-year-old man was still inside the truck unable to move with a gunshot wound to his back hip. Officers surrounded the area and quickly caught the other three occupants of the truck, according to Lohrke.
Multiple weapons were recovered from that scene, he said. Argenis Daniel Ramirez-Saedt, 19, and Jose Luis Muñoz-Lugo, 24, were each arrested for investigation of two counts of murder and five counts of discharge of a firearm. Rosalio Alvarez, 19, and a 17-year-old were also arrested and expected to be booked into the Salt Lake County Jail and juvenile detention for investigation of the same charges.
Detectives also went back to the house where the shootout occurred and served a search warrant late Tuesday. Although no arrests were made, Lohrke said investigators found 10 to 12 people inside and seized several more guns.
The recent violence in Kearns that appears to be tied to gang rivalry has become a top priority for the Unified Police Department.
"We want to ensure the citizens of Kearns that they are safe here. We not only want to tell them, but we want them to see our presence out there," Lohrke said.
Wednesday morning, 14 Unified police officers were assigned to the Kearns area. Normally, three officers and a supervisor are assigned to the area.
Lohrke said detectives from the Metro Gang Unit, Special Operations and the Motors Division will be used to supplement the usual Kearns patrol units around the clock for the forseeable future.
"We have cops everywhere. We will continue this effort as long as it takes," he said, while also noting that it would be "stupid" for gangs to try any retaliation right now. "We want it to be known we are here."
A town hall meeting to discuss the gang problem is scheduled for 6:30 p.m. Thursday at Kearns High School.
Ramirez-Saedt already faces misdemeanor charges of bringing a loaded gun onto school property a year ago, according to court records. In that case, Ramirez-Saedt went inside Granger High School during school hours and failed to check in with the office. When police caught up with him, they discovered that he was carrying a loaded firearm that "was concealed on his person and was readily accessible for immediate use," the charges state. He also had a knife.
On June 29, a warrant was issued for Ramirez-Saedt for failing to show up to court on that case. He was arrested on Sunday but was released later that day due to jail overcrowding, according to jail and court records.
A GoFundMe account has been set up to support the families of Woodard and Pace.
"Losing a brother and co-worker is something that you never see happening. Lloyd was the most genuine, hard working and down to earth guy out there! It's going to be hard not working with you. I'm going to miss you dogg, Rest In Paradise!" one man who works at Progressive Plumbing and Piping. Inc., wrote on Facebook.
"My heart will remember your name till the day I die my friend. You will be missed!!" wrote another co-worker.
Pace's Facebook page says he attended South Pearl Academy in Draper. Woodard's Facebook page states she is originally from Portola Valley, California. She has also lived in Woods Cross and West Valley City.
Pat Reavy Pat is a veteran police and courts reporter for the Deseret News and KSL.
@DNewsCrimeTeam
preavy@deseretnews.com

redpajama_set_name: RedPajamaCommonCrawl


ARLINGTON, Texas (AP) Albert Pujols isn't reflecting yet. He and the Angels have too much work to do.
Pujols hit a two-run home run, the 569th of his career, and Nick Tropeano threw 6 2/3 strong innings to help Los Angeles beat the Texas Rangers 2-0.
The Angels have won eight of their last 11 games.
Pujols' homer in the third inning tied him for 12th in career homers with Rafael Palmeiro.
Pujols is batting .340 in his last 12 games after hitting only .132 over his first 18. That has raised his season batting average to .228. His lowest figure for a full season is the .244 that he hit last season.
Tropeano (3-2) allowed four hits and one walk while striking out six. He has held opponents to two runs or fewer in seven of nine starts and lowered his ERA to 2.86. He retired 10 straight before Elvis Andrus' two-out single in the seventh inning.
Texas' Derek Holland (3-4) pitched 6 2/3 innings, matching his longest outing of the season, and allowed two runs on seven hits.
Joe Smith got his sixth save of the season. Angels relievers stranded two runners in the seventh inning, three in the eighth and one in the ninth. Texas was 0 for 7 with runners in scoring position.
Pujols' home run followed a double by Mike Trout, who had two hits. Trout is hitting .352 in his last 37 games after opening the season at .185.
Before the game, Texas announced that Yu Darvish would make his first major league start since August 2014 on Saturday against Pittsburgh. Darvish had Tommy John surgery in March 2015.
Angels starters have held opponents to two total runs in their last 27 innings.
This is happening with a rotation that has lacked C.J. Wilson all season, got one start from Andrew Heaney and recently lost Garrett Richards for a prolonged period - all because of injury.
Johnny Giavotella had two hits to extend his hitting streak to a career-high 12 games. Giavotella also made a diving catch on a broken-bat liner hit by Adrian Beltre in the eighth inning with the bases loaded.
Angels: Closer Huston Street (oblique) is scheduled to throw in an extended spring training game on Friday after pitching a simulated inning at Globe Life Park on Monday.
Rangers: LF Josh Hamilton (knee), sidelined since March, will have another surgery on June 8 and will miss the entire season. OFs Shin-Soo Choo (hamstring) and Drew Stubbs (toe) were placed on the 15-day disabled list on Monday, Choo retroactive to Saturday.
Angels RHP Jhoulys Chacin (1-2) has two no-decisions since being acquired from Atlanta. He allowed four earned runs in 4 1/3 innings in the Angels' win over the Dodgers on Thursday. The four May starts made by Rangers LHP Martin Perez (1-4) have resulted in two losses and two no-decisions despite a 2.59 ERA. In Perez's nine starts this season, the Rangers have scored one run or fewer five times.


text:
Moscow Metro launches biometric Face Pay across entire network
The Moscow Metro has announced the full launch of its new Face Pay service, which enables passengers to pay their fares using facial biometrics at all metro stations.
The news was announced by the deputy mayor of Moscow for Transport, Maksim Liksutov, in his personal column on October 15. The new system has been fully tested by passengers and employees of Moscow for Transport since the beginning of 2021.
To use the new payment technology, passengers connect their Troika transport card and bank card to the Moscow Metro mobile app, and then upload their image. The payment procedure works the same as when passengers pass through a turnstile using a bank card. Passengers approach the turnstile, a camera captures their image, verifies it and then the passenger can pass through.
According to the Moscow Metro, all data is securely encrypted. The live technology also distinguishes a real face from a photograph making it impossible for passengers to pay for rides using images of other people.
In his column, Liksutov said that at some stations, which have less light, the system might operate a little slower, "much like a smartphone camera that needs more time to recognize a person in the dark or in a poorly lit place," he wrote.
According to Liksutov, Moscow city is the largest user of biometric payments in the world. Due to the variety of payment methods, over the past 10 years, the queues at the metro ticket offices have decreased by 3.3 times, and with the launch of Face Pay, they are set to reduce even more.
According to the forecasts of the Moscow Department of Transport, in the next two to three years, 10-15% of passengers will regularly use Face Pay. The Moscow Metro will adjust the number of turnstiles for Face Pay if the demand for the new service grows. Currently, at least one turnstile has been installed at each station entrance, with some stations having up to three.
Within a day after the launch, about 25,000 people registered for the Face Pay service.
Maksim Liksutov, the deputy mayor of Moscow for Transport using Face Pay:
https://www.traffictechnologytoday.com/wp-content/uploads/2021/10/Face-Pay-launched.mp4
The post Moscow Metro launches biometric Face Pay across entire network appeared first on megapolisnews.com.