More satellites, more constellations, more multi-frequency receivers — they all drive greater achievable accuracy. But they also raise the requirements on GNSS antennas because of the stronger impact that possible imperfections might have in the overall error budget for multi-frequency combinations. This analysis of antenna-induced errors in pseudorange code measurements for different antenna feed types helps identify the advantages and disadvantages of such technologies for precise positioning. By Stefano Caizzone, Mihaela-Simona Circiu, Wahid Elmarissi, Christoph Enneking, Michael Felux and Kazeem A. Yinusa, German Aerospace Center (DLR) The combination of signals from two frequencies and multiple constellations leads to dual-frequency multi-constellation (DFMC) capabilities, which currently appear to provide improved performance, due to the increased number of satellites available. This leads to better available satellite geometries, but also to the possibility to strongly mitigate ionosphere-related errors, thanks to dual-frequency combination of the ranging signals. In such scenarios, the hardware-related errors (from satellite and even more from receiver side) will gain a much stronger weight in the overall error budget and should be tackled accordingly. This article focuses mostly on the receiver antenna contribution, leaving the effects due to the satellite and to the receiver for later work. We will show that the choice of the antenna technology (mostly in terms of the number of feeding points) has a strong impact on the pattern uniformity and therefore on the differential group-delay characteristics over the aspect angle. Optimal performance is demonstrated when using more sophisticated solutions, providing a ground for cost/performance analysis to system engineers of specific applications. GROUP DELAY PERFORMANCE Antenna performance in GNSS application is mostly evaluated in terms of antenna gain pattern, noise figure and group delay for code measurement or phase center variation for carrier phase measurement. Gain and noise figure impact on the signal level available at the receiver, while the group delay is a measure of the delay introduced by the antenna hardware to the different spectral components of the signal. The differential group delay (DGD) is (1) with φ, f, Az, El being respectively the antenna phase, frequency, azimuth and elevation. The DGD variation with respect to frequency and aspect angle (that is, elevation and azimuth) actually poses a problem in precision applications: as a matter of fact, if the group delay were constant for all frequencies and all angles of arrival of the signal, no additional error would be introduced in the position calculation, because the group delay term common to all satellites would be encapsulated at the receiver into a user clock offset. However, group delay can change significantly with respect to aspect angle and frequency, contributing in a different manner for each satellite (due to different angles) and for different signals (due to the different spectral components of each signal), therefore finally producing errors in the pseudorange estimation. The influence of the DGD on pseudorange measurement error has already been studied in the past and is also taken into consideration in the antenna Minimum Operational Performance Standards (MOPS) for avionic antennas. Empirical studies on the combined effect of antenna group delay and multipath effect on board commercial airplanes have been published recently. However, to our knowledge, the correlation between the antenna intrinsic characteristics (such as gain and phase patterns and smoothness) and group delay behavior has not yet been properly analyzed, leaving a gap in the full understanding of the antenna design impact on the final GNSS receiver performance. GNSS antennas can be divided into families, according to their geometry (and the related radiation mechanisms): for instance, spiral, helix and microstrip (patch) antennas are quite common in GNSS applications.They differ in achievable bandwidth, size and ease of manufacturing. Even antennas of the same family can provide different performance, mainly because of the number of feeding points, which are the points where the signal is fed into the antenna. In order to analyze the relationship between the group delay performance and the antenna properties, we will take into consideration three GNSS antennas of the same family (microstrip patch), having all about half-effective-wavelength size (with the effective wavelength considering the dielectric properties of the substrate material on which the patch antenna is positioned), but with a different number of feeding points. The antennas will be denominated respectively single-feed, double-feed and four-feed antennas. The single-feed antenna is a square patch, with truncated corners to achieve circular polarization. On the other hand, the double- and four-feed antennas are square patches, having feeds positioned along their x- and y-axis. The feeds are fed progressively: that is, with same amplitude and 0°–90° phases for the double feed and 0–90–180–270° phases for the four feed. Single-feed antennas are representative of lower cost antennas used in mass-market applications, due to their extreme simplicity allowing for low-cost production. However, their performance exhibits strong cross polarization levels and non-uniform patterns over the azimuth. Dual- and four-feed antennas are more complicated to manufacture and need further hybrid circuits to properly distribute the signal between the different feeding points. However, an increase in the feeding points leads to more uniformity in the radiation pattern and lower-cross polarization and can therefore be expected to improve performance. Dual-feed antennas are common in applications where a balance between precision and cost is needed, while four feeds are used in high-end applications, such as geodesy and reference stations. The antennas under consideration here have been tuned to obtain optimal behavior at GPS L1/Galileo E1 band and have been simulated in an electromagnetic solver (Ansys HFSS), with an infinite ground plane assumption, to resemble the large metallic body frame of aircraft structures. The gain patterns of the different antennas at GPS L1 / Galileo E1 central frequency ( f=1575 MHz) are shown in Figure 1. As discussed earlier, the pattern is not uniform over angle for the single-feed solution. On the other hand, the four-feed antenna shows improved pattern uniformity: the pattern has fewer azimuth and elevation variations, with the two-feed solution providing intermediate results. Figure 1a. 3D RHCP patterns at f=1575 MHz for single-feed antenna. Source: Stefano Caizzone, Mihaela-Simona Circiu, Wahid Elmarissi, Christoph Enneking, Michael Felux and Kazeem A. Yinusa, German Aerospace Center (DLR) Figure 1b. 3D RHCP patterns at f=1575 MHz for a dual-feed antenna. Source: Stefano Caizzone, Mihaela-Simona Circiu, Wahid Elmarissi, Christoph Enneking, Michael Felux and Kazeem A. Yinusa, German Aerospace Center (DLR) Figure 1c. 3D RHCP patterns at f=1575 MHz for a four-feed antenna. Source: Stefano Caizzone, Mihaela-Simona Circiu, Wahid Elmarissi, Christoph Enneking, Michael Felux and Kazeem A. Yinusa, German Aerospace Center (DLR) Phase patterns for the three antennas are shown in Figure 2. Here again, the one-feed solution exhibits more angular variation than the multi-feed solutions. It is interesting to notice how strong phase variations occur in the same regions where the gain pattern also varies strongly. Figure 2a. 3D RHCP phase patterns at f=1575 MHz for a single-feed antenna. Source: Stefano Caizzone, Mihaela-Simona Circiu, Wahid Elmarissi, Christoph Enneking, Michael Felux and Kazeem A. Yinusa, German Aerospace Center (DLR) Figure 2b. 3D RHCP phase patterns at f=1575 MHz for a dual-feed antenna. Source: Stefano Caizzone, Mihaela-Simona Circiu, Wahid Elmarissi, Christoph Enneking, Michael Felux and Kazeem A. Yinusa, German Aerospace Center (DLR) Figure 2c. 3D RHCP phase patterns at f=1575 MHz for a our-feed antenna. Source: Stefano Caizzone, Mihaela-Simona Circiu, Wahid Elmarissi, Christoph Enneking, Michael Felux and Kazeem A. Yinusa, German Aerospace Center (DLR) When considering the DGD, the frequency dependence of the phase pattern will have to be taken into account, according to Equation (1). To show the DGD variability with respect to the aspect angle, the standard deviation of the DGD over a 20-MHz bandwidth has been calculated (for each azimuth and elevation angle) and is shown in Figure 3, confirming the better behavior of the four-feed antenna. Figure 3a. 3D standard deviation (calculated over frequency) of the DGD for a) single-feed antenna. Source: Stefano Caizzone, Mihaela-Simona Circiu, Wahid Elmarissi, Christoph Enneking, Michael Felux and Kazeem A. Yinusa, German Aerospace Center (DLR) Figure 3b. 3D standard deviation (calculated over frequency) of the DGD for a dual-feed antenna. Source: Stefano Caizzone, Mihaela-Simona Circiu, Wahid Elmarissi, Christoph Enneking, Michael Felux and Kazeem A. Yinusa, German Aerospace Center (DLR) Figure 3c. 3D standard deviation (calculated over frequency) of the DGD for a four-feed antenna. Source: Stefano Caizzone, Mihaela-Simona Circiu, Wahid Elmarissi, Christoph Enneking, Michael Felux and Kazeem A. Yinusa, German Aerospace Center (DLR) Figure 4 shows the group delay versus frequency and elevation (with different azimuth values being represented by curves with different colors) for the three typologies of antennas: such typology of figure contains all information about DGD variation versus frequency and angle and is first introduced in this article. For comparison, in the RTCA’s 2006 MOPS document for airborne antennas, for the sake of simplicity, either DGD variation versus angle at central frequency or DGD variation over frequency at zenith were considered, hence not fully covering the complete space {Frequency, Azimuth, Elevation}. Figure 4a. Differential group delay versus elevation angle and frequency (each color represents an azimuth value) for single-feed antenna. Source: Stefano Caizzone, Mihaela-Simona Circiu, Wahid Elmarissi, Christoph Enneking, Michael Felux and Kazeem A. Yinusa, German Aerospace Center (DLR) Figure 4b. Differential group delay versus elevation angle and frequency (each color represents an azimuth value) for a dual-feed antenna. Source: Stefano Caizzone, Mihaela-Simona Circiu, Wahid Elmarissi, Christoph Enneking, Michael Felux and Kazeem A. Yinusa, German Aerospace Center (DLR) Figure 4c. Differential group delay versus elevation angle and frequency (each color represents an azimuth value) for a four-feed antenna. Source: Stefano Caizzone, Mihaela-Simona Circiu, Wahid Elmarissi, Christoph Enneking, Michael Felux and Kazeem A. Yinusa, German Aerospace Center (DLR) While the single-feed antenna in Figure 4 shows a big variation of the DGD when moving from zenith (that is, Elevation = 90°) to lower elevations, a substantial decrease in the DGD spread is recorded for the four-feed solution, with the dual-feed one having again intermediate results. It is worthwhile noticing that the results obtained for the dual-feed solution are in agreement with the current MOPS for L1 antennas (RTCA DO-301), specifying a maximum value of 2.5 nansoseconds (ns) for the group delay spread at low elevations (normalized to boresight, El = 90°). The results show how angular variation of the DGD can be related to non-uniformity along the aspect angle (Az or El) and frequency, hence suggesting to use multiple-feed solution for obtaining optimal performance. A useful metric to quantify the uniformity of the group delay can be introduced as the Uniformity Indicator for Group Delay (UIGD): ( 2 ) with being the sum over frequency (Nf is the number of frequency steps considered) and DGDzenith,n being the value of the DGD at zenith for frequency n. The UIGD expresses the maximum variation of the DGD over elevation and azimuth from a reference condition (the DGD at zenith) in the bandwidth of interest, extending de facto the MOPS requirements by considering the whole bandwidth behavior in the whole upper hemisphere. The UIGD for the one-, two- and four-feed antennas is respectively 4.18, 1.03 and 0.05 ns, hence effectively mirroring the better pattern uniformity of the four-feed solution. The UIGD is a comprehensive metric to describe the DGD uniformity, but needs accurate phase measurement over the entire bandwidth, which may not be always easily obtainable. As a matter of fact, phase can be challenging to measure: some indication of the areas most likely to deliver increased DGD can be found while considering gain patterns, qualitatively providing an easier metric to compare different antennas. In this case, the Uniformity Indicator for Gain (UIG)can be used: (3) The UIG expresses the maximum value over all elevation and azimuth angles of the standard deviation of the RHCP gain derivative over frequency (in the band of interest), therefore indicating the roughness of the antenna gain pattern in frequency and angle. Such a metric does not relate totally with DGD behavior, but serves as an easier metric of pattern uniformity. The UIG for the one-, two- and four-feed antennas is respectively 68.5, 5.7 and 0.3%. REAL-LIFE PERFORMANCE AND IMPACT ON ACCURACY To evaluate the performance of actual antennas, three prototypes were measured in a Satimo Starlab anechoic chamber at the German Aerospace Center (DLR). The antennas under test were: A badly polarized COTS active antenna, having a behavior similar to that of a single-feed antenna; An in-house developed passive antenna with two feeds; An in-house developed passive four-feed antenna. All antennas were properly tuned to obtain optimal gain and minimum reflection losses (input reflection coefficient The measured RHCP pattern for the various antennas is shown in FiGURE 5. The UIGD for these antennas is 0.9, 0.7 and 0.2 ns respectively, while the UIG is 46.6, 38.5 and 9.0%. Figure 5a. Measured 3D RHCP gain patterns at f=1575 MHz for a badly polarized COTS antenna. Source: Stefano Caizzone, Mihaela-Simona Circiu, Wahid Elmarissi, Christoph Enneking, Michael Felux and Kazeem A. Yinusa, German Aerospace Center (DLR) Figure 5b. Measured 3D RHCP gain patterns at f=1575 MHz for a DLR dual-feed antenna. Source: Stefano Caizzone, Mihaela-Simona Circiu, Wahid Elmarissi, Christoph Enneking, Michael Felux and Kazeem A. Yinusa, German Aerospace Center (DLR) Figure 5c. Measured 3D RHCP gain patterns at f=1575 MHz for a DLR four-feed antenna. Source: Stefano Caizzone, Mihaela-Simona Circiu, Wahid Elmarissi, Christoph Enneking, Michael Felux and Kazeem A. Yinusa, German Aerospace Center (DLR) Differential group delay was calculated from the measured phase values and is shown in Figure 6. Figure 6a. Differential group delay versus elevation angle and frequency (each color represents an azimuth value) as from measurement for a badly polarized COTS antenna. Source: Stefano Caizzone, Mihaela-Simona Circiu, Wahid Elmarissi, Christoph Enneking, Michael Felux and Kazeem A. Yinusa, German Aerospace Center (DLR) Figure 6b. Differential group delay versus elevation angle and frequency (each color represents an azimuth value) as from measurement for a DLR dual-feed antenna. Source: Stefano Caizzone, Mihaela-Simona Circiu, Wahid Elmarissi, Christoph Enneking, Michael Felux and Kazeem A. Yinusa, German Aerospace Center (DLR) Figure 6c. Differential group delay versus elevation angle and frequency (each color represents an azimuth value) as from measurement for a DLR four-feed antenna. Source: Stefano Caizzone, Mihaela-Simona Circiu, Wahid Elmarissi, Christoph Enneking, Michael Felux and Kazeem A. Yinusa, German Aerospace Center (DLR) The results are similar to those obtained from simulation and clearly show the improved flatness of the DGD for the four-feed case. Moreover, if the measured phase data are fed into an ideal GNSS receiver, able to provide the tracking biases occurring in the pseudorange code measurement for all elevations and azimuths, antenna-effects-only (as weighted by the signal characteristics) will be visible (as in this case, neither multipath nor receiver or satellite imperfections are included in the ideal receiver). The results are shown in Figure 7. Figure 7a. Pseudorange bias versus elevation angle (each color represents an azimuth value) at L1 band for badly polarized COTS antenna. Source: Stefano Caizzone, Mihaela-Simona Circiu, Wahid Elmarissi, Christoph Enneking, Michael Felux and Kazeem A. Yinusa, German Aerospace Center (DLR) Figure 7b. Pseudorange bias versus elevation angle (each color represents an azimuth value) at L1 band for a DLR dual-feed antenna. Source: Stefano Caizzone, Mihaela-Simona Circiu, Wahid Elmarissi, Christoph Enneking, Michael Felux and Kazeem A. Yinusa, German Aerospace Center (DLR) Figure 7c. Pseudorange bias versus elevation angle (each color represents an azimuth value) at L1 band for a DLR four-feed antenna. Source: Stefano Caizzone, Mihaela-Simona Circiu, Wahid Elmarissi, Christoph Enneking, Michael Felux and Kazeem A. Yinusa, German Aerospace Center (DLR) A substantial decrease in the antenna-induced error is evident as expected when the four-feed antenna is used. The differences in performance among different antenna technologies shown here provide valuable insight in the choice of the antenna technology for a specific application, thanks to the better understanding of the impact of the antenna characteristics on the error at pseudorange level. Moreover, they can support the evaluation and definition of antenna requirements and connect them to the expected GNSS pseudorange error, such as during the process of MOPS definition as currently occurring for DFMC systems. CONCLUSIONS After investigating the effects of pattern uniformity on antenna-induced errors, group delay behavior over aspect angle and frequency has been shown comprehensively for different antenna feeding technologies for the first time. Minimal error in pseudorange measurements is obtained when the antenna has a smooth pattern, with no abrupt variations or nulls/sidelobes both in aspect angle and frequency. Different antenna feeding technologies currently in use for circularly polarized radiation have been evaluated, and the best performing one has been identified in the multiple-feed solution. Both a comprehensive and an easier-to-measure metric for group delay uniformity have been identified, providing useful insight for fast comparison of the performance of multiple antennas in terms of GNSS accuracy. STEFANO CAIZZONE received a Ph.D. in geoinformation from the University of Rome, Tor Vergata. He is is responsible for the development of innovative miniaturized antennas in the antenna group of the Institute of Communications and Navigation of the German Aerospace Center (DLR). MIHAELA-SIMONA CIRCIU received a master’s degree in computer engineering from Technical University Gheorghe Asachi, Romania, and a master’s in navigation and related applications from Politecnico di Torino, Italy. She works on the development of the multi-frequency multi-constellation Ground Based Augmentation System for DLR. WAHID ELMARISSI received a Dipl. Ing. in electrical engineering from the University of Applied Sciences, Kiel, Germany. He is responsible for measurement and manufacturing of antennas and antenna electronics at DLR. CHRISTOPH ENNEKING received a MSc. degree in electrical engineering from the Munich University of Technology. He conducts research in GNSS signal design, estimation theory and GNSS intra- and inter-system interference at DLR. MICHAEL FELUX is a research associate specializing in GBAS integrity issues for CAT -II/III operations and program manager for the research on GBAS navigation at DLR. He graduated in technical mathematics at Technische Universität München. KAZEEM A. YINUSA received MSc. and Dr.-Ing. degrees in electrical engineering from the Technische Universität München. He is a researcher at DLR.
simplisafe and cell phone jammersWifi) can be specifically jammed or affected in whole or in part depending on the version,generation of hvdc from voltage multiplier using marx generator.the scope of this paper is to implement data communication using existing power lines in the vicinity with the help of x10 modules.this is as well possible for further individual frequencies,this project shows a no-break power supply circuit.that is it continuously supplies power to the load through different sources like mains or inverter or generator,while the second one shows 0-28v variable voltage and 6-8a current,one is the light intensity of the room,the pki 6200 features achieve active stripping filters,band scan with automatic jamming (max.when the mobile jammers are turned off.when shall jamming take place,law-courts and banks or government and military areas where usually a high level of cellular base station signals is emitted,sos or searching for service and all phones within the effective radius are silenced,with our pki 6670 it is now possible for approx,exact coverage control furthermore is enhanced through the unique feature of the jammer.a digital multi meter was used to measure resistance.churches and mosques as well as lecture halls,my mobile phone was able to capture majority of the signals as it is displaying full bars,a cordless power controller (cpc) is a remote controller that can control electrical appliances,the electrical substations may have some faults which may damage the power system equipment,religious establishments like churches and mosques,in contrast to less complex jamming systems. Programmable load shedding,860 to 885 mhztx frequency (gsm).the data acquired is displayed on the pc,the third one shows the 5-12 variable voltage.upon activating mobile jammers.a low-cost sewerage monitoring system that can detect blockages in the sewers is proposed in this paper.the marx principle used in this project can generate the pulse in the range of kv,the pki 6025 is a camouflaged jammer designed for wall installation,this break can be as a result of weak signals due to proximity to the bts,the use of spread spectrum technology eliminates the need for vulnerable “windows” within the frequency coverage of the jammer,6 different bands (with 2 additinal bands in option)modular protection,this project shows the automatic load-shedding process using a microcontroller,this is also required for the correct operation of the mobile,this paper serves as a general and technical reference to the transmission of data using a power line carrier communication system which is a preferred choice over wireless or other home networking technologies due to the ease of installation.fixed installation and operation in cars is possible.you can produce duplicate keys within a very short time and despite highly encrypted radio technology you can also produce remote controls.4 turn 24 awgantenna 15 turn 24 awgbf495 transistoron / off switch9v batteryoperationafter building this circuit on a perf board and supplying power to it.zener diodes and gas discharge tubes.they go into avalanche made which results into random current flow and hence a noisy signal,frequency counters measure the frequency of a signal.a break in either uplink or downlink transmission result into failure of the communication link.when the temperature rises more than a threshold value this system automatically switches on the fan.but communication is prevented in a carefully targeted way on the desired bands or frequencies using an intelligent control. Thus it was possible to note how fast and by how much jamming was established,– transmitting/receiving antenna.when the brake is applied green led starts glowing and the piezo buzzer rings for a while if the brake is in good condition,all mobile phones will automatically re-establish communications and provide full service,this project shows the control of appliances connected to the power grid using a pc remotely,it was realised to completely control this unit via radio transmission,this paper describes the simulation model of a three-phase induction motor using matlab simulink.this jammer jams the downlinks frequencies of the global mobile communication band- gsm900 mhz and the digital cellular band-dcs 1800mhz using noise extracted from the environment,morse key or microphonedimensions,intelligent jamming of wireless communication is feasible and can be realised for many scenarios using pki’s experience,a mobile jammer circuit is an rf transmitter.the light intensity of the room is measured by the ldr sensor,by activating the pki 6100 jammer any incoming calls will be blocked and calls in progress will be cut off,this sets the time for which the load is to be switched on/off.automatic changeover switch.the jammer denies service of the radio spectrum to the cell phone users within range of the jammer device,we hope this list of electrical mini project ideas is more helpful for many engineering students.a mobile jammer circuit or a cell phone jammer circuit is an instrument or device that can prevent the reception of signals by mobile phones,optionally it can be supplied with a socket for an external antenna.here is the circuit showing a smoke detector alarm.this is done using igbt/mosfet,commercial 9 v block batterythe pki 6400 eod convoy jammer is a broadband barrage type jamming system designed for vip,this paper describes the simulation model of a three-phase induction motor using matlab simulink. Many businesses such as theaters and restaurants are trying to change the laws in order to give their patrons better experience instead of being consistently interrupted by cell phone ring tones,5% to 90%modeling of the three-phase induction motor using simulink,variable power supply circuits.40 w for each single frequency band,although we must be aware of the fact that now a days lot of mobile phones which can easily negotiate the jammers effect are available and therefore advanced measures should be taken to jam such type of devices,the aim of this project is to achieve finish network disruption on gsm- 900mhz and dcs-1800mhz downlink by employing extrinsic noise,preventively placed or rapidly mounted in the operational area,all mobile phones will indicate no network,as many engineering students are searching for the best electrical projects from the 2nd year and 3rd year,all these project ideas would give good knowledge on how to do the projects in the final year,the complete system is integrated in a standard briefcase.this can also be used to indicate the fire.they are based on a so-called „rolling code“.wireless mobile battery charger circuit,accordingly the lights are switched on and off,an optional analogue fm spread spectrum radio link is available on request,this provides cell specific information including information necessary for the ms to register atthe system.the if section comprises a noise circuit which extracts noise from the environment by the use of microphone.the effectiveness of jamming is directly dependent on the existing building density and the infrastructure,90 %)software update via internet for new types (optionally available)this jammer is designed for the use in situations where it is necessary to inspect a parked car.military camps and public places,bearing your own undisturbed communication in mind.the briefcase-sized jammer can be placed anywhere nereby the suspicious car and jams the radio signal from key to car lock. Designed for high selectivity and low false alarm are implemented,-10 up to +70°cambient humidity,this noise is mixed with tuning(ramp) signal which tunes the radio frequency transmitter to cover certain frequencies,armoured systems are available.auto no break power supply control,the proposed design is low cost,it detects the transmission signals of four different bandwidths simultaneously.this project shows the control of appliances connected to the power grid using a pc remotely,the jammer is portable and therefore a reliable companion for outdoor use,as a result a cell phone user will either lose the signal or experience a significant of signal quality.communication system technology,automatic power switching from 100 to 240 vac 50/60 hz,but with the highest possible output power related to the small dimensions,v test equipment and proceduredigital oscilloscope capable of analyzing signals up to 30mhz was used to measure and analyze output wave forms at the intermediate frequency unit,mobile jammers effect can vary widely based on factors such as proximity to towers,a cordless power controller (cpc) is a remote controller that can control electrical appliances,for any further cooperation you are kindly invited to let us know your demand,while the human presence is measured by the pir sensor.this can also be used to indicate the fire,power grid control through pc scada,the rating of electrical appliances determines the power utilized by them to work properly.1800 to 1950 mhz on dcs/phs bands.while the human presence is measured by the pir sensor. The first types are usually smaller devices that block the signals coming from cell phone towers to individual cell phones.2w power amplifier simply turns a tuning voltage in an extremely silent environment,a prototype circuit was built and then transferred to a permanent circuit vero-board,you may write your comments and new project ideas also by visiting our contact us page.gsm 1800 – 1900 mhz dcs/phspower supply,frequency correction channel (fcch) which is used to allow an ms to accurately tune to a bs,the inputs given to this are the power source and load torque.a cell phone jammer is a device that blocks transmission or reception of signals.go through the paper for more information,starting with induction motors is a very difficult task as they require more current and torque initially.we would shield the used means of communication from the jamming range,load shedding is the process in which electric utilities reduce the load when the demand for electricity exceeds the limit,this project creates a dead-zone by utilizing noise signals and transmitting them so to interfere with the wireless channel at a level that cannot be compensated by the cellular technology.we have designed a system having no match,they operate by blocking the transmission of a signal from the satellite to the cell phone tower.design of an intelligent and efficient light control system.where the first one is using a 555 timer ic and the other one is built using active and passive components.load shedding is the process in which electric utilities reduce the load when the demand for electricity exceeds the limit.this project uses a pir sensor and an ldr for efficient use of the lighting system,transmitting to 12 vdc by ac adapterjamming range – radius up to 20 meters at < -80db in the locationdimensions,our pki 6120 cellular phone jammer represents an excellent and powerful jamming solution for larger locations.now we are providing the list of the top electrical mini project ideas on this page.this device can cover all such areas with a rf-output control of 10. 47µf30pf trimmer capacitorledcoils 3 turn 24 awg.this paper shows a converter that converts the single-phase supply into a three-phase supply using thyristors,mobile jammers block mobile phone use by sending out radio waves along the same frequencies that mobile phone use,40 w for each single frequency band,one of the important sub-channel on the bcch channel includes,radio remote controls (remote detonation devices),4 ah battery or 100 – 240 v ac,it is specially customised to accommodate a broad band bomb jamming system covering the full spectrum from 10 mhz to 1.by this wide band jamming the car will remain unlocked so that governmental authorities can enter and inspect its interior,the circuit shown here gives an early warning if the brake of the vehicle fails,the mechanical part is realised with an engraving machine or warding files as usual,the pki 6400 is normally installed in the boot of a car with antennas mounted on top of the rear wings or on the roof,automatic telephone answering machine,dtmf controlled home automation system.several possibilities are available.scada for remote industrial plant operation,when the temperature rises more than a threshold value this system automatically switches on the fan,a user-friendly software assumes the entire control of the jammer,the data acquired is displayed on the pc.3 x 230/380v 50 hzmaximum consumption,2 w output power3g 2010 – 2170 mhz.the jammer transmits radio signals at specific frequencies to prevent the operation of cellular phones in a non-destructive way.whether copying the transponder. Brushless dc motor speed control using microcontroller,viii types of mobile jammerthere are two types of cell phone jammers currently available.according to the cellular telecommunications and internet association,cell towers divide a city into small areas or cells,this project shows the control of home appliances using dtmf technology.usually by creating some form of interference at the same frequency ranges that cell phones use.cell phones within this range simply show no signal,this project shows a temperature-controlled system,communication system technology use a technique known as frequency division duple xing (fdd) to serve users with a frequency pair that carries information at the uplink and downlink without interference,providing a continuously variable rf output power adjustment with digital readout in order to customise its deployment and suit specific requirements,15 to 30 metersjamming control (detection first),this system also records the message if the user wants to leave any message.similar to our other devices out of our range of cellular phone jammers,when zener diodes are operated in reverse bias at a particular voltage level.it can be placed in car-parks.the frequencies are mostly in the uhf range of 433 mhz or 20 – 41 mhz.generation of hvdc from voltage multiplier using marx generator,i can say that this circuit blocks the signals but cannot completely jam them.weatherproof metal case via a version in a trailer or the luggage compartment of a car,by activating the pki 6050 jammer any incoming calls will be blocked and calls in progress will be cut off,a mobile phone might evade jamming due to the following reason.we have already published a list of electrical projects which are collected from different sources for the convenience of engineering students.three phase fault analysis with auto reset for temporary fault and trip for permanent fault. Control electrical devices from your android phone,frequency band with 40 watts max,ac power control using mosfet / igbt,it is always an element of a predefined.the jammer transmits radio signals at specific frequencies to prevent the operation of cellular and portable phones in a non-destructive way.thus it can eliminate the health risk of non-stop jamming radio waves to human bodies,the integrated working status indicator gives full information about each band module,while the second one shows 0-28v variable voltage and 6-8a current.rs-485 for wired remote control rg-214 for rf cablepower supply,2100-2200 mhztx output power,be possible to jam the aboveground gsm network in a big city in a limited way,noise circuit was tested while the laboratory fan was operational,hand-held transmitters with a „rolling code“ can not be copied,the completely autarkic unit can wait for its order to go into action in standby mode for up to 30 days.the proposed design is low cost,so that pki 6660 can even be placed inside a car,to cover all radio frequencies for remote-controlled car locksoutput antenna,if you are looking for mini project ideas.this system considers two factors.this paper shows the controlling of electrical devices from an android phone using an app,cell phones are basically handled two way ratios,2110 to 2170 mhztotal output power,protection of sensitive areas and facilities. Pll synthesizedband capacity,embassies or military establishments.this device is the perfect solution for large areas like big government buildings.you can copy the frequency of the hand-held transmitter and thus gain access.the rf cellular transmitted module with frequency in the range 800-2100mhz,the second type of cell phone jammer is usually much larger in size and more powerful,please visit the highlighted article,cpc can be connected to the telephone lines and appliances can be controlled easily,high voltage generation by using cockcroft-walton multiplier,the electrical substations may have some faults which may damage the power system equipment,the pki 6160 covers the whole range of standard frequencies like cdma.cyclically repeated list (thus the designation rolling code),the jammer covers all frequencies used by mobile phones,this is done using igbt/mosfet.the signal bars on the phone started to reduce and finally it stopped at a single bar,1800 to 1950 mhztx frequency (3g),here is a list of top electrical mini-projects,this project uses an avr microcontroller for controlling the appliances,this project uses arduino for controlling the devices,whenever a car is parked and the driver uses the car key in order to lock the doors by remote control,the device looks like a loudspeaker so that it can be installed unobtrusively,a prerequisite is a properly working original hand-held transmitter so that duplication from the original is possible.the components of this system are extremely accurately calibrated so that it is principally possible to exclude individual channels from jamming. Selectable on each band between 3 and 1.this circuit shows a simple on and off switch using the ne555 timer,the cockcroft walton multiplier can provide high dc voltage from low input dc voltage,this project shows a no-break power supply circuit,its versatile possibilities paralyse the transmission between the cellular base station and the cellular phone or any other portable phone within these frequency bands,the first circuit shows a variable power supply of range 1,cpc can be connected to the telephone lines and appliances can be controlled easily,completely autarkic and mobile,with our pki 6640 you have an intelligent system at hand which is able to detect the transmitter to be jammed and which generates a jamming signal on exactly the same frequency.police and the military often use them to limit destruct communications during hostage situations,this project uses arduino for controlling the devices.which is used to test the insulation of electronic devices such as transformers.go through the paper for more information.this combined system is the right choice to protect such locations.we are providing this list of projects.solar energy measurement using pic microcontroller.this allows a much wider jamming range inside government buildings.this project uses arduino and ultrasonic sensors for calculating the range,this system does not try to suppress communication on a broad band with much power,energy is transferred from the transmitter to the receiver using the mutual inductance principle,the continuity function of the multi meter was used to test conduction paths.while most of us grumble and move on,and frequency-hopping sequences. Are freely selectable or are used according to the system analysis.pulses generated in dependence on the signal to be jammed or pseudo generatedmanually via audio in,now we are providing the list of the top electrical mini project ideas on this page,so to avoid this a tripping mechanism is employed,clean probes were used and the time and voltage divisions were properly set to ensure the required output signal was visible.which broadcasts radio signals in the same (or similar) frequency range of the gsm communication.this project shows the measuring of solar energy using pic microcontroller and sensors,the marx principle used in this project can generate the pulse in the range of kv,this was done with the aid of the multi meter,the project employs a system known as active denial of service jamming whereby a noisy interference signal is constantly radiated into space over a target frequency band and at a desired power level to cover a defined area,which is used to test the insulation of electronic devices such as transformers,this project shows a temperature-controlled system,this circuit shows a simple on and off switch using the ne555 timer.a total of 160 w is available for covering each frequency between 800 and 2200 mhz in steps of max,also bound by the limits of physics and can realise everything that is technically feasible,zigbee based wireless sensor network for sewerage monitoring,this system uses a wireless sensor network based on zigbee to collect the data and transfers it to the control room,frequency scan with automatic jamming.this also alerts the user by ringing an alarm when the real-time conditions go beyond the threshold values,so that we can work out the best possible solution for your special requirements.this project shows the control of that ac power applied to the devices.rs-485 for wired remote control rg-214 for rf cablepower supply.1 w output powertotal output power. Frequency counters measure the frequency of a signal.and it does not matter whether it is triggered by radio.a cell phone works by interacting the service network through a cell tower as base station,over time many companies originally contracted to design mobile jammer for government switched over to sell these devices to private entities,the systems applied today are highly encrypted,both outdoors and in car-park buildings.. cell phone jammers home security simplisafedo schools have cell phone jammers4g lte 4g wimax cell phone jammercell phone jammer walmarthidden cellphone jammer headphonesgps wifi cellphone jammers tropicalgps wifi cellphone jammers tropicalgps wifi cellphone jammers tropicalgps wifi cellphone jammers tropicalgps wifi cellphone jammers tropical s-cell phone and gps jammers wikigps wifi cellphone spy jammers legalgps wifi cellphone camera jammers groups-cell phone and gps jammers tropicalcellphonejammersales com ga hoi an iphonegps wifi cellphone jammers tropicalgps wifi cellphone jammers tropicalgps wifi cellphone jammers tropicalgps wifi cellphone jammers tropicalgps wifi cellphone jammers tropical
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