• Build a cell phone jammer circuit,video cellphone jammer archives,Getting there more safely INNOVATION INSIGHTS with Richard Langley It’s all physics.  How things work, that is. You’ve heard me say that before in this column, but I suppose I’m a...

Build a cell phone jammer circuit - video cellphone jammer archives

Build a cell phone jammer circuit - video cellphone jammer archives

iAe0u_vLY9Zl@outlook.com

Offline
  • 2021/07/21
Getting there more safely INNOVATION INSIGHTS with Richard Langley It’s all physics. How things work, that is. You’ve heard me say that before in this column, but I suppose I’m a little biased (or realistic) as my first degree is in physics — applied physics, to be more precise. Mind you, some chemists might disagree that it’s all down to physics. But as Sheldon Cooper in the popular American TV sitcom The Big Bang Theory stated in a radio interview with real science journalist Ira Flatow following his apparent discovery of the first stable super-heavy element, “Yes, yes, I’d be a physicist with a Nobel in chemistry. Everyone laugh at the circus freak. You know, I don’t need to sit here and take this, Flatow. It is because of bullies like you, every day more and more Americans are making the switch to television.” But in all seriousness, it really was physicists who first explained the physical phenomena associated with a range of technologies that had to be understood before global navigation satellite systems could become a reality. From orbital mechanics, to relativity theory, to semiconductors, to transatmospheric propagation of radio signals, to atomic clocks, the fundamental understanding of how these worked was provided by physicists. This was particularly true for atomic clocks. An atomic clock, like any clock, consists of two basic components: a resonator or oscillator and a counter. The oscillator generates a stable frequency, whose cycles are counted, converted to units of seconds, minutes, hours and perhaps days, and continuously displayed. This is the case whether we are describing a wristwatch with a quartz crystal oscillator or an atomic clock whose oscillator is made up of atoms undergoing quantum energy transitions. A crystal oscillator is stimulated to vibrate at its design frequency and thereby generate a fluctuating electrical current with that frequency. The atomic oscillator works thanks to the principles of quantum physics. Atoms have energies, but the energies are quantized, meaning that only specific energy levels are possible. An atom may exist at a particular energy level and spontaneously transition to a lower energy level and in so doing emit electromagnetic radiation (such as radio waves or light) of a specific frequency equal to the change in energy divided by a fundamental physical constant called Planck’s constant, named after Max Planck, who introduced it in 1900. The atom can be stimulated to return to the higher energy level by exposing it to radiation of that same exact frequency. A practical atomic oscillator can be constructed by confining a collection of atoms in an enclosure and bathing them in electromagnetic radiation from a tunable generator. By automatically tuning the frequency of the generator to maximize the number of stimulated atoms through a feedback loop, a very pure and constant frequency will result. The first clocks based on an energy transition of the cesium atom were developed in the mid-1950s. Later on, clocks based on energy transitions of the rubidium and hydrogen atoms were developed. By the 1960s, commercial rack-mountable cesium and rubidium clocks became available. But a need existed for miniaturized atomic clocks that could be easily embedded in equipment requiring a very stable frequency source. Funded in part by the Defense Advanced Research Projects Agency, the first chip-scale atomic clock was demonstrated by physicists in 2004, and by 2011, a chip-scale atomic clock based on a cesium atom transition became commercially available. In this month’s column, we look at how chip-scale atomic clocks can help us navigate more safely by allowing a GNSS receiver to position itself more accurately even with only three satellites in view, and to protect itself by being able to detect a sophisticated spoofing attempt. Physics — isn’t it wonderful! GNSS positioning and navigation are based on one-way range measurements. Synchronization of the receiver and satellite timescales is carried out with respect to a third time scale of higher stability, such as GNSS system time, by introducing so-called clock errors. To account for the time and frequency offsets of the satellites, the user can obtain appropriate corrections from the broadcast navigation message in real time. In post-processing, more accurate corrections are provided by various products of the International GNSS Service (IGS). Due to the generally poor accuracy and limited long-term frequency stability of a quartz oscillator built into a GNSS receiver, the receiver clock error has to be estimated epoch-by-epoch. This is the typical case for single-point positioning (SPP) based on code (pseudorange) observations only. This comes with certain drawbacks: The up-coordinate is determined two to three times less precisely than the horizontal coordinates, Higher dilution of precision values are obtained than in the hypothetical case of trilateration, High correlations of up to 99 percent between the receiver’s up-coordinate and clock error persist, and At least four satellites are necessary for positioning. Especially in the case of kinematic positioning, this situation can be significantly improved by using a more stable (atomic) clock for the receiver and introducing the information about its frequency stability into the estimation process. This approach is called receiver clock modeling (RCM), and basically requires that the integrated clock noise is smaller than the receiver noise during the modeling interval. Besides SPP, this method can also be applied in a common-clock setup in relative positioning using single-differenced observations (which, by their nature, contain more information) instead of typically used double-differenced observations, or precise point positioning. The recent development of chip-scale atomic clocks (CSACs) offers the required frequency stability and accuracy, and opens up the possibility of using atomic clocks in real kinematic GNSS applications without any severe restrictions regarding power supply or environmental influences on the clocks. When connecting one of these clocks to a GNSS receiver, replacing or steering the internal oscillator accordingly, and modeling its behavior in a physically meaningful way instead of epoch-wise estimation, the navigation performance can be improved distinctly. The receiver clock parameter absorbs signal delays common to all simultaneous line-of-sight signals whether these delays represent the physical clock or any other common delay. Thus, it is especially vulnerable to delays caused by jammers or spoofers. If the clock behavior is predictable, information about jamming or spoofing can be retrieved, and thus the integrity of the positioning solution can be improved. Chip-Scale Atomic Clocks For our test purposes, we used two different commercially available CSACs, dubbed CSAC A and CSAC B. To gain knowledge about their frequency stabilities, we compared them against an active hydrogen maser at the Physikalisch-Technische Bundesanstalt (PTB), Germany’s official metrology institute. We analyzed the raw fractional phase measurements and computed individual Allan variances for our devices. The resulting frequency stabilities are shown in FIGURE 1. Clock Model Basically, a clock is an oscillator generating a sinusoidal signal with a given nominal frequency coupled with a frequency counter. The deviation of the signal’s nominal frequency with respect to a reference time scale can be described by a frequency offset and drift plus random frequency fluctuations. In the time domain, the resulting clock error δt, that is, the difference between nominal time t and the time read simultaneously on the clock, can be approximated by the following equation: (1)   with systematic time offset b0, frequency offset b1, frequency drift b2, and random noise x(t,t0). Thus, the main (deterministic) part of a clock model can be described by a quadratic polynomial. The more interesting characteristics of a clock are contained in the underlying noise processes. The time-dependent Allan deviation (ADEV) enables the determination of a modeling or predicting interval τp over which receiver clock modeling is physically meaningful; that is, the integrated clock noise x(t,t0) is smaller than GNSS receiver noise: (2)   The noise σrx of a typical commercial GNSS receiver can be assessed to approximately one percent of the chip or wavelength of the signal in use, such as 3 meters, 0.3 meter, or 2 millimeters for C/A-code, P-code, or L1 carrier-phase observations, respectively. To apply the knowledge gained about the devices’ frequency stabilities, appropriate models for GNSS data analysis should be established. One prerequisite is that the clock noise has to be well below the GNSS receiver noise; that is, the integrated random frequency fluctuations of CSACs cannot be resolved by the GNSS observations in use. We assume typical values for code and ionosphere-free carrier-phase observations from modern geodetic GNSS receivers of 1 meter and 5 millimeters, respectively. Since these observations are phase-based measures, we can model the dominating underlying noise process as white-noise phase modulation (WPM) over time. The corresponding graphs are depicted in FIGURE 1 as dashed lines. The intersection points between these lines and the ADEV curves define maximal time intervals Δt for physically meaningful receiver clock modeling in our case study. Depending on the CSAC in use, RCM is applicable over time intervals of at least ten minutes and up to one hour in C/A-code-based applications, such as SPP. GNSS Applications We have tested and validated our receiver clock modeling approaches for GNSS navigation. Kinematic Experiment We carried out a real kinematic experiment on a cart track in farm fields with an approximately 500 × 800 square meter area with only a few natural obstructions in the form of a tree-lined lane (see FIGURE 2). The basic measurement configuration consisted of four GNSS receivers running the same firmware version connected to a GNSS antenna via an active signal splitter. Three of these receivers were fed by the 10-MHz signals of our CSACs. For comparison purposes, the fourth receiver was driven by its internal quartz oscillator. Each test drive with our motor vehicle lasted approximately 8 to 10 minutes. We recorded GPS and GLONASS data with a sampling interval of one second. (Only GPS-based results are described herein.) That was also the case for our temporary local reference station, which consisted of a GNSS antenna mounted on a tripod and connected to another GNSS receiver. Hence, we were able to generate reference solutions for the vehicle trajectories in relative positioning mode with baselines of up to only some hundred meters, yielding 3D coordinate accuracies below 20 centimeters. The RCM algorithms presented here were implemented in the Institut für Erdmessung GNSS Matlab Toolbox. To compute a typical real-time SPP navigation solution based on GPS C/A-code observations only, broadcast ephemerides were used. Tropospheric and ionospheric signal delays were corrected by the Saastamoinen and Klobuchar models, respectively. [Click on an image to enlarge it.] FIGURE 1. Allan deviations of investigated atomic clocks and GPS ionosphere-free carrier and C/A-code observation noise modeled as white-noise phase modulation (WPM) over time. FIGURE 2. Test track. The yellow ellipse marks a treed lane with signal obstructions. Precision and Accuracy Two of the most important GNSS performance parameters are the precision and accuracy of the coordinate solution. FIGURE 3 shows topocentric coordinate differences with respect to the reference trajectory and clock-error time series of the receiver driven by its internal quartz oscillator, estimated without RCM. This is typical for almost all end users. The (linearly detrended) receiver clock error exhibits values between roughly −100 and +200 nanoseconds, which is typical for a quartz oscillator. The noise of the coordinates is in the range of 20–25 centimeters in the horizontal components and about 50 centimeters in the up-component, respectively. Furthermore, certain coordinate offsets are visible due to remaining systematic effects such as ionospheric delay and orbit errors. We could attribute these effects thanks to repeated analysis runs with different correction models such as precise IGS final orbits or by forming the ionosphere-free linear combination. Hence, the assessment of the accuracy of the results is difficult since it chiefly depends on the applied correction models, and it is less influenced by receiver clock modeling. Without use of RCM, the three receivers connected to the CSACs show similar behavior in the coordinate domain. However, the clock residuals become very small compared to those of the internal oscillator and amount to only a couple of nanoseconds at most. As an example, FIGURE 4 depicts the results for CSAC A. Even over a relatively short period of time of approximately eight minutes, this oscillator shows a significant frequency drift, which we have to account for in RCM. Note that this is also true for the device’s oven-controlled crystal oscillator (OCXO) post-filtered signal. When applying RCM, as expected, no changes in the time series of the north and east coordinates occur, but a strong decrease of the up-coordinate residuals is clearly visible. The noise level is up to 20–30 centimeters. Due to the applied polynomial clock model, the clock residuals are also reduced. Thanks to the increasing number of epochs/observations contributing to the estimation of the clock parameters, the course of these residuals gets smoother over time. Furthermore, spikes in the up-coordinate time series at around minutes five to seven caused by sudden signal obstructions are almost eliminated thanks to RCM. Also, when applying RCM, there are no improvements in the horizontal components, but the scatter of the up-coordinates is decreased in the range of 48 percent (CSAC B) to 58 percent (CSAC A). Our second RCM approach based on an existing extended Kalman filter clock model shows comparable results. The most obvious difference to a sequential least-squares approach is that the spikes in the up-coordinate and clock residual time series at around minutes five to seven are not smoothed as strongly. Reliability and Integrity Reliability and integrity are very important GNSS performance parameters, especially for real-time and safety-of-life critical applications. In general, we distinguish between internal and external reliability, which are both measures for the robustness of the parameter estimation against blunders in the observation data. Thereby, good reliability makes it easier to identify and remove gross errors and outliers in GNSS data analysis. Internal reliability is calculated in terms of so-called minimal detectable biases (MDBs) of the GNSS observations. These values determine lower bounds for gross observation errors so that these can still be detectable. External reliability describes the influence of these MDBs on the parameter estimates. In our experiments, we found reductions in the size of the MDBs of up to 16 percent. As a consequence, the vertical protection level — a measure of integrity — is also improved. Positioning with 3 Satellites Generally, GNSS positioning requires at least four satellites in view to solve the equation system for the four unknowns. This can become a severe restriction in difficult environments such as urban canyons. Taking benefits of an oscillator of high accuracy, with known and predictable frequency stability, enables positioning using only three satellites. This approach enhances GNSS continuity and availability, and is called clock coasting. Thanks to the stability of CSACs, the GNSS observations are corrected by an additional receiver clock term, which is computed from the latest clock-coefficient estimates. To show the effects of this method, we generated two artificial partial satellite outages so that only observations on only three satellites remain. The latter were chosen in such a way that typical situations in an urban canyon were simulated; that is, only satellites with high elevation angles were visible to the receiver. The resulting coordinate and clock time series are depicted in FIGURE 5. When coasting through periods with only three satellites available, the horizontal coordinates become approximately two to three times noisier (1–2 meters). Due to the poor observation geometry, an additional offset of about 1 meter is induced in the north component during the first partial outage. However, the noise of the up-coordinate is only slightly increased in both of the outage periods, although a significant drift is visible during the first one. Most likely, this is because the coefficients used for clock coasting are only based on 60 epochs up until that time. During the second partial outage this drifting behavior vanishes independently of the satellite geometry. Due to the fact that the clock time series are linearly detrended and a linear clock polynomial is applied, the corresponding residuals shown in FIGURE 5 equal zero during the coasting periods. The presented approaches for RCM and clock coasting are applicable in multi-GNSS positioning and timing data analysis, too, where we also have to consider inter-system biases. Thanks to the high temporal stability of these biases, they can be modeled by a polynomial in the same sense as the receiver clock error. [Click on an image to enlarge it.] FIGURE 3. Topocentric coordinate deviations with respect to the reference trajectory and clock errors. The receiver is driven by its internal oscillator. No receiver clock modeling was applied in a sequential least-squares adjustment. Note the different y-axis scales. FIGURE 4. Topocentric coordinate deviations with respect to the reference trajectory and clock errors for a receiver connected to the CSAC A signal. The results without receiver clock modeling are depicted in black and blue. The results applying a quadratic polynomial for clock modeling in a sequential least-squares adjustment are shown in red. FIGURE 5. Topocentric coordinate deviations with respect to the reference trajectory and clock errors. The receiver is connected to CSAC B. The solution is obtained from a sequential least-squares adjustment with clock coasting from minutes one to two and five to seven. Spoofing Detection Jamming and spoofing of GNSS signals have become major threats to GNSS positioning and timing. Although these authentication issues have been well known since the beginnings of GPS, they have become more severe in recent years due to the greatly increased number of applications that rely on (highly) accurate GNSS positioning and timing. Experiment A spoofing attack’s goal is for the signal tracking loops of a target receiver to acquire the spoofing signal, and then pull its navigation solution away from the authentic position. So as not be detected by the target receiver, the common delay of the spoofing signals — which will be absorbed by the receiver’s clock-error estimate — must not deviate significantly from the receiver’s authentic clock error. This means that the injected delay has to be as small as possible so that it cannot be separated from the typical random frequency (and thus time) fluctuations of the oscillator driving the receiver. To simulate a spoofing attack, we set up an experiment consisting of two GNSS receivers, one driven by its internal quartz oscillator, and one connected to CSAC B, both recording the same GNSS signals via a signal splitter. The input signal of the latter comes from an active coaxial switch, which allows us to switch between two different antennas in less than 1 second. Both antennas in our measurement configuration were mounted on tripods. However, one antenna was connected to a commercial GNSS repeater, which generates an additional delay, and its output signals were transmitted via cable to the coaxial switch (see FIGURE 6). When switched to the antenna without the repeater, the receivers recorded authentic signals. When switched to the repeater, they recorded spoofed signals. The location of the repeater antenna ranges from 2 to 25 meters away from the authentic antenna, thereby introducing different delays — in addition to the repeater delay — into the signal processing of the two receivers. We assume that a short delay of about 2 meters (7 nanoseconds) is more difficult for receivers to detect than a delay of about 25 meters (83 nanoseconds). Whenever the signal path is switched from the authentic antenna to the repeater antenna, this should result in a jump in the clock-error time series. Combined with the known frequency stability of the receivers’ oscillators, we can establish a hypothesis test for the significance of such a clock-error jump. For each new location of the repeater antenna, the measurement procedure was the same. We recorded authentic and spoofed data four times alternating for two minutes with a data rate of 1 Hz. FIGURE 6. Measurement configuration of a spoofing detection experiment. Results FIGURES 7 and 8 show the original clock-time offsets for two different locations of the repeater antenna as recorded by the receivers, and the corresponding predicted clock states from the Kalman filter. The jumps in each clock-error time series are more or less clearly visible, especially in the case of the 2-meter distance. For the latter, the hypothesis test of the temperature-controlled crystal oscillator (TCXO) always accepts the alternative in favor of the null hypothesis; that is, from a statistical standpoint, no spoofing attack is detectable. This is because of the small signal delay attributable to the measurement geometry, which cannot be properly separated from random time deviations caused by the TCXO’s low frequency stability. On the contrary, even for this short distance between the spoofing and authentic antennas, every start and end of the four spoofing attacks were detected. As an example, FIGURE 8 shows the results for a larger distance (around 14 meters). In this case, all spoofing attacks can be properly detected by both the TCXO- and the CSAC-controlled receivers. The seven-times-increased distance ensures that even the low-cost TCXO inside the receiver combined with a sophisticated receiver internal clock estimation is capable of spoofing detection by monitoring its clock states. FIGURE 7. Original and predicted receiver time-offset states after a straight line fit for a receiver driven by its internal TCXO and connected to CSAC B, respectively. The repeater antenna is located about 2 meters away from the authentic antenna. FIGURE 8. As for Figure 7 but with the repeater antenna located about 14 meters away from the authentic antenna. Conclusions In this article, we have proposed a deterministic approach for receiver clock modeling in a sequential least-squares adjustment by applying a linear or quadratic clock polynomial whose coefficients are updated each consecutive epoch. As a prerequisite, an individual characterization of the frequency stabilities of three miniaturized atomic clocks was carried out with respect to the phase of an active hydrogen maser showing an overall good agreement with manufacturers’ data. A real kinematic experiment was carried out with two chip-scale atomic clocks, and typical code-based GPS navigation solutions were computed. We showed that the precision of the up-coordinate time series are improved by up to 58 percent, depending on the clock in use. Furthermore, internal and external reliability were significantly enhanced. Additionally, it was shown that our algorithm is capable of coasting through periods of partial satellite outages with only three satellites in view. This increases availability and continuity of GNSS positioning with poor satellite coverage caused by high shadowing effects or multipath, for example. Finally, we investigated the benefits of an atomic clock in spoofing detection and showed first results. Our approach, based on a Kalman filter and a hypothesis test, enhances the detectability of a spoofer when using a CSAC instead of the receiver’s internal oscillator, especially in the case of small signal delays injected by the spoofing device, which helps to identify a sophisticated spoofer very quickly. Manufacturers We used two different CSACs: a Jackson Labs (jackson-labs.com) LN (CSAC A) and a Microsemi Quantum SA.45s (CSAC B). For the kinematic experiment, we used four JAVAD GNSS Delta TRE-G3T receivers connected to a NovAtel 703 GGG antenna via an active signal splitter. The local reference station consisted of a Leica (leica-geosystems.us) AX1202GG antenna connected to a Leica GRX1200+ GNSS receiver. A JAVAD Delta TRE-G3T was used in the spoofing experiment. Disclaimer The authors do not recommend any of the instruments tested. It is also to be noted that the performance of the equipment presented in this article depends on the particular environment and the individual instruments in use. Acknowledgments This article is based, in part, on the paper “Benefits of Chip Scale Atomic Clocks in GNSS Applications” presented at ION GNSS+ 2015, the 28th International Technical Meeting of the Satellite Division of The Institute of Navigation, held Sept. 14–18, 2015, in Tampa, Florida. The authors would like to thank Andreas Bauch and Thomas Polewka, who are both with PTB, for their support during execution and analysis of the clock comparisons, and Achim Hornbostel from the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt) for discussions on spoofing experiments. We also thank IGS and its participating agencies for their GNSS products, which were a valuable contribution to our case study. Our work was funded by the Federal Ministry of Economics and Technology of Germany. Further Reading • Authors’ Conference Paper “Benefits of Chip Scale Atomic Clocks in GNSS Applications” by T. Krawinkel and S. Schön in Proceedings of ION GNSS+ 2015, the 28th International Technical Meeting of the Satellite Division of The Institute of Navigation, Tampa, Florida, Sept. 14–18, 2015, pp. 2867–2874. • Chip-Scale Atomic Clocks and GNSS Applications “Reducing the Jitters: How a Chip-Scale Atomic Clock Can Help Mitigate Broadband Interference” by F.-C. Chan, M. Joerger, S. Khanafseh, B. Pervan and O. Jakubov in GPS World, Vol. 25, No. 5, May 2014, pp. 44–50. “Time for a Better Receiver: Chip-Scale Atomic Frequency References” by J. Kitching in GPS World, Vol. 18, No. 11, Nov. 2007, pp. 52–57. • Time, Frequency and Clocks “A Historical Perspective on the Development of the Allan Variances and Their Strengths and Weaknesses” by D.W. Allan and J. Levine in IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, Vol. 63, No. 4, April 2016, pp. 513–519, doi: 10.1109/TUFFC.2016.2524687. Time – From Earth Rotation to Atomic Physics by D.D. McCarthy and P.K. Seidelmann, published by Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, Germany, 2009. “Special Issue: Fifty Years of Atomic Time-Keeping: 1955 to 2005,” Metrologia, Vol. 42, No. 3, June 2005. The Measurement of Time: Time, Frequency and the Atomic Clock by C. Audoin and B. Guinot, published by Cambridge University Press, Cambridge, U.K., 2001. The Science of Timekeeping by D.W. Allan, N. Ashby and C.C. Hodge, Hewlett Packard (now Agilent Technologies) Application Note 1289, 1997. “The Role of the Clock in a GPS Receiver” by P. Misra in GPS World, Vol. 7, No. 4, April 1996, pp. 60–66. “Time, Clocks, and GPS” by R.B. Langley in GPS World, Vol. 2, No. 10, Nov./Dec. 1991, pp. 38–42. • Clock Modeling Feasibility and Impact of Receiver Clock Modeling in Precise GPS Data Analysis by U. Weinbach, Ph.D. dissertation, Gottfried Wilhelm Leibniz Universität Hannover, Hannover, Germany, Wissenschaftliche Arbeiten der Fachrichtung Geodäsie und Geoinformatik der Leibniz Universität Hannover, Nr. 303, and Deutsche Geodätische Kommission bei der Bayerischen Akademie der Wissenschaften, Reihe C, Dissertationen Heft Nr. 692, 2013. “Time and Frequency (Time-Domain) Characterization, Estimation, and Prediction of Precision Clocks and Oscillators“ by D.W. Allan in IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, Vol. UFFC-34, No. 6, Nov. 1987, pp. 647–654, doi: 10.1109/T-UFFC.1987.26997. “Relationship Between Allan Variances and Kalman Filter Parameters” by A.J. van Dierendonck, J. McGraw and R.G. Brown in Proceedings of the Sixteenth Annual Precise Time and Time Interval (PTTI) Applications and Planning Meeting, Greenbelt, Maryland, Nov. 27–29, 1984, pp. 273–292. • Spoofing “GNSS Spoofing Detection: Correlating Carrier Phase with Rapid Antenna Motion” by M.L. Psiaki with S.P. Powell and B.W. O’Hanlon in GPS World, Vol. 24, No. 6, June 2013, pp. 53–58. “Assessing the Spoofing Threat” by T.E. Humphreys, P.M. Kintner, Jr., M.L. Psiaki, B.M. Ledvina and B.W. O’Hanlon in GPS World, Vol. 20, No. 1, January 2009, pp. 28–38.


,,

build a cell phone jammer circuit

Computer wise dv-1280-3 ac adapter 12v dc 1000ma class 2 transfo,linearity lad6019ab4 ac adapter 12vdc 4a-(+)- 2.5x5.5mm 100-24,key/transponder duplicator 16 x 25 x 5 cmoperating voltage,the proposed design is low cost.health o meter adpt 6 ac adapter 12v dc 500ma class 2 transforme,this project shows automatic change over switch that switches dc power automatically to battery or ac to dc converter if there is a failure,nokia acp-12u ac adapter 5.7vdc 800ma used 1x3.5mm cellphone 35.5% – 80%dual-band output 900,kodak k8500 li-on rapid battery charger dc4.2v 650ma class 2,pantech pta-5070dus ac dc adapter 5v 700ma cellphone battery cha,elementech au1361202 ac adapter 12vdc 3a -(+) used2.4 x 5.5 x.insignia e-awb135-090a ac adapter 9v 1.5a switching power supply,the output of that circuit will work as a.ge 5-1075a ac adapter 6vdc 200ma 7.5v 100ma used -(+) 2x5x10.9mm.simple mobile jammer circuit diagram cell phone jammer circuit explanation,phase sequence checker for three phase supply,jobmate battery charger 18vdc used for rechargeable battery,apple m8010 ac adapter 9.5vdc 1.5a +(-) 25w 2x5.5mm 120vac power,ibm 02k6746 ac adapter 16vdc 4.5a -(+) 2.5x5.5mm 100-240vac used,conair spa-2259 ac adapter 18vac 420ma used ~(~) 2x5.5x11mm roun,smoke detector alarm circuit,dve dsa-009f-05a ac adapter +5vdc 1.8a 9w switching adapter.hios cb-05 cl control box 20-30vdc 4a made in japan.925 to 965 mhztx frequency dcs.avaya sa41-118a ac adapter 9vdc 700ma 13w -(+)- power supply,mb132-075040 ac adapter 7.5vdc 400ma used molex 2 pin direct plu,black&decker ua-090020 ac adapter 9vac 200ma 5w charger class 2,chd-hy1004 ac adapter 12v 2a 5v 2a used multiple connectors,similar to our other devices out of our range of cellular phone jammers.motorola 5864200w16 ac adapter 9vdc 300ma 2.7w 8w power supply.with a maximum radius of 40 meters,it was realised to completely control this unit via radio transmission,wlg q/ht001-1998 film special transformer new 12vdc car cigrate.ault sw 130 ka-00-00-f-02 ac adapter 60vdc 0.42a medical power s.electra 26-26 ac car adapter 6vdc 300ma used battery converter 9.li shin 0226b19150 ac adapter 19vdc 7.89a -(+) 2.5x5.5mm 100-240.targus apa63us ac adapter 15v-24v 90w power supply universal use,mgp f10603-c ac adapter 12v-14v dc 5-4.28a used 2.5 x 5.4 x 12.1,changzhou linkie lk-dc-210040 ac adapter 21vdc 400ma used 2.1 x,i introductioncell phones are everywhere these days,gn netcom bce-gn9120 wireless base amplifire with charger sil ud.crestron gt-21097-5024 ac adapter 24vdc 1.25a new -(+)- 2x5.5mm,ingenico pswu90-2000 ac adapter 9vdc 2a -(+) 2.5x5.5 socket jack,dell 0335a1960 ac adapter 19v dc 3.16a -(+)- used 3x5mm 90° ite,delta adp-60jb ac adapter 19v dc 3.16a used 1.9x5.4x11.5mm 90.atlinks usa 5-2629 ac adapter 9vdc 300ma power supply class 2 tr,oem ad-0760dt ac adapter 7.5vdc 600ma used-(+)- 2.1x5.4x10mm.lind pb-2 auto power adapter 7.5vdc 3.0a macintosh laptop power,yuyao wj-y666-12 ac adapter 12vdc 500ma used -(+) 2.1x5.5x12mm r,hipro hp-02036d43 ac adapter 12vdc 3a -(+) 36w power supply,compaq pa-1530-02cv ac adapter 18.5vdc 2.7a used 1.7x5mm round b,all the tx frequencies are covered by down link only.delta adp-90cd db ac adapter 19vdc 4.74a used -(+)- 2x5.5x11mm,samsung astec ad-8019 ac adapter 19vdc 4.2a used -(+) 0.7x3x5x9,kodak k3000 ac adapter 4.2vdc 1.2a used li-on battery charger e8,a low-cost sewerage monitoring system that can detect blockages in the sewers is proposed in this paper,sanyo js-12050-2c ac adapter 12vdc 5a used 4pin din class 2 powe.

Symbol sbl-a12t 50-24000-060 ac adapter 48vdc 2.5a power supply,nexxtech 2200502 ac adapter 13.5vdc 1000ma used -(+) ite power s,intercom dta-xga03 ac adapter 12vdc 3a -(+) 1.2x3.5mm used 90° 1,65w-dlj104 ac adapter 19.5v dc 3.34a dell laptop power supply.globetek gt-21089-0909-t3 ac adapter 9vdc 1a 9w ite power supply.logitech tesa5-0500700d-b ac adapter 5vdc 300ma used -(+) 0.6x2.,brushless dc motor speed control using microcontroller,cgo supports gps+glonass+beidou data in,symbol vdn60-150a battery adapter 15vdc 4a used -(+)- 2.5x5.5mm,delta adp-65jh db ac adapter 19vdc 3.42a used 1.5x5.5mm 90°rou,its built-in directional antenna provides optimal installation at local conditions.finecom 34w-12-5 ac adapter 5vdc 12v 2a 6pin 9mm mini din dual v,daino lite limited dmpi60 ac adapter 12vac 60va 2pin transformer,fujitsu seb100p2-19.0 ac adapter 19vdc 4.22a -(+) used 2.5x5.5mm.sony vgp-ac19v10 ac adapter 19.5vdc 4.7a notebook power supply.sony vgp-ac10v2 ac adapter 10.5vdc 1.9a genuine for vaio mini pc,another big name in the cell phone signal booster market.3com sc102ta1503b03 ac adapter 15vdc 1.2a power supply,replacement sadp-65kb d ac adapter 19v 3.42a used 1.8x5.4x12mm 9,automatic telephone answering machine,globtek gt-4076-0609 ac adapter 9vdc 0.66a -(+)- used 2.6 x 5.5,pride mobility elechg1024 ea1089a ac acid battery charger adapte,pentax battery charger d-bc7 for optio 555's pentax d-li7 lithiu,ault symbol sw107ka0552f01 ac adapter 5v dc 2a new power supply,compact dual frequency pifa …,motorola fmp5358a ac adapter 5v 850ma power supply.bionx hp1202l3 01-3444 ac adaptor 37vdc 2a 4pin xlr male used 10,rim psm05r-068r dc adapter 6.8v dc 0.5a wall charger ite,ktec ka12a120120046u ac adapter 12vac 1200ma ~(~)~ 2x5.5mm linea.condor hk-i518-a12 12vdc 1.5a -(+) 2x5.5mm used ite power supply,soneil 2403srd ac adapter 24vdc 1.5a 3pin xlr connector new 100-,this interest comes from the fundamental objective,ibm 02k6549 ac adapter 16vdc 3.36a used -(+) 2.5x5.5mm 90° degre,the marx principle used in this project can generate the pulse in the range of kv,hon-kwang hk-u-090a060-eu european ac adapter 9v dc 0-0.6a new.acbel ad9014 ac adapter 19vdc 3.42a used -(+)- 1.8x4.8x10mm,nec adp-90yb c ac adapter 19v dc 4.74a power supply,t027 4.9v~5.5v dc 500ma ac adapter phone connector used travel,lishin lse9802a1660 ac adapter 16vdc 3.75a -(+)- used 2.5x5.5x12.pa-1900-05 replacement ac adapter 19vdc 4.74a used 1.7x4.7mm -(+,iluv dys062-090080w-1 ac adapter 9vdc 800ma used -(+) 2x5.5x9.7m,d-link cg2412-p ac adapter 12vdc 2a -(+) used 1.2x3.75mm europe,bk-aq-12v08a30-a60 ac adapter 12vdc 8300ma -(+) used 2x5.4x10mm,motorola odmpw00000002-100 ac adapter 5vdc 800ma used -(+)- cell,retrak whafr24084001 ac adapter 19vdc 3.42a used 4.2x6mm power s,mobile / cell phone jammer/blocker schematic diagram circu.ac adapter used car charger tm & dc comics s10,71109-r ac adapter 24v dc 500ma power supply tv converter,ge nu-90-5120700-i2 ac adapter 12v dc 7a used -(+) 2x5.5mm 100-2,ibm 02k6542 ac adapter 16vdc 3.36a -(+) 2.5x5.5mm 100-240vac use,wireless mobile battery charger circuit,practical peripherals dv-8135a ac adapter 8.5vac 1.35amp 2.3x5mm.samsung ap04214-uv ac adapter 14vdc 3a -(+) tip 1x4.4x6x10mm 100.quectel quectel wireless solutions has launched the em20.is someone stealing your bandwidth,li shin gateway 0225c1965 19v dc 3.42a -(+)- 1.9x5.5mm used ite,ad-2425-ul ac dc adapter 24v 250ma transformateur cl ii power su.

Belkin car cigarette lighter charger for wireless fm transmitter.sc02 is an upgraded version of sc01,as many engineering students are searching for the best electrical projects from the 2nd year and 3rd year,ault t57-182200-j010g ac adapter 18v ac 2200ma used.you may write your comments and new project ideas also by visiting our contact us page,umec up0451e-12p ac adapter 12vdc 3.75a (: :) 4pin mini din 10mm,v infinity emsa240167 ac adapter 24vdc 1.67a -(+) used 2x5.5mm s.sony adp-8ar a ac adapter 5vdc 1500ma used ite power supply.component telephone u090050d ac dc adapter 9v 500ma power supply,wahl adt-1 ac adapter 1.2vdc 2000ma used -(+) 0.9x3.7x7.5mm roun,braun 3 709 ac adapter dc 1.3w class 2 power supply plug in char,thermo gastech 49-2163 ac adapter 12.6vdc 220/70ma battery charg,the paralysis radius varies between 2 meters minimum to 30 meters in case of weak base station signals.trendnet tpe-111gi(a) used wifi poe e167928 100-240vac 0.3a 50/6.shenzhen jhs-q05/12-s334 ac adapter 12vdc 5v 2a s15 34w power su,top global wrg20f-05ba ac adapter 5vdc 4a -(+)- 2.5x5.5mm used.depending on the already available security systems.motorola psm5037b travel charger 5.9v 375ma ac power supply spn5,yamaha pa-1210 ac adapter 12vdc 1a used -(+) 2x5.5x10mm round ba,ct std-1203 ac adapter -(+) 12vdc 3a used -(+) 2.5x5.4mm straigh.s15af125120 ac adapter 12.5vdc 1200ma used -(+) 2x5.5x11mm rou,ast 230137-002 ac adapter 5.2vdc 3a 7.5vdc 0.4a power supply cs7.dv-6520 ac adapter 6.5vdc 200ma 6w used 2.5x11.1mm trs connector,sylvan fiberoptics 16u0 ac adapter 7.5vdc 300ma used 2.5x5.5mm.battery mc-0732 ac adapter 7.5v dc 3.2a -(+) 2x5.5mm 90° 100-240,voyo xhy050200lcch ac adapter 5vdc 2a used 0.5x2.5x8mm round bar.which broadcasts radio signals in the same (or similar) frequency range of the gsm communication,90 % of all systems available on the market to perform this on your own,dell fa90ps0-00 ac adapter 19.5vdc 4.62a 90w used 1x5x7.5xmm -(+,shen zhen zfxpa01500090 ac adapter 9vdc 1.5a used -(+) 0.5 x 2.5,dell da90pe3-00 ac adapter 19.5v 4.62a pa-3e laptop power suppl,phase sequence checking is very important in the 3 phase supply,liteon pa-1480-19t ac adapter (1.7x5.5) -(+)- 19vdc 2.6a used 1.,it employs a closed-loop control technique,modeling of the three-phase induction motor using simulink,here is the project showing radar that can detect the range of an object,emachines lse0202c1890 ac adapter 18.5vdc 4.9a power supply,st-c-075-18500380ct ac adapter 18.5vdc 2.7a 3.5a 3.8a used 1.6x4,oem ads0248-w 120200 ac adapter 12v dc 2a used -(+)- 2.1x5.5mm.this mobile phone displays the received signal strength in dbm by pressing a combination of alt_nmll keys,creative ua-1450 ac adapter 13.5v power supply i-trigue damage,anti jammer bluetooth wireless earpiece unlimited range,replacement dc359a ac adapter 18.5v 3.5a used,ibm 11j8627 ac adapter 19vdc 2.4a laptop power supply,sony ac-l200 ac adapter 8.4vdc 1.7a camcorder power supply.toshiba pa3378e-2aca ac adapter 15vdc 5a used -(+)- 3x6.5mm.gn netcom a30750 ac adapter 7.5vdc 500ma used -(+) 0.5x2.4mm rou,then went down hill in a matter of seconds,dell pa-1131-02d ac adapter 19.5vdc 6.7aa 918y9 used -(+) 2.5x5.,cisco aa25-480l ac adapter 48vdc 0.38a -(+)- 100-240vac 2.5x5.5m,cpc can be connected to the telephone lines and appliances can be controlled easily,hp 0950-2852 class 2 battery charger nicd nimh usa canada.toshiba pa3201u-1aca ac adapter 15v 5a used -(+) 3.1x6.5mm lapto.this project shows charging a battery wirelessly.hp f1011a ac adapter 12vdc 0.75a used -(+)- 2.1x5.5 mm 90 degree,kxd-c1000nhs12.0-12 ac dc adapter used +(-) 12vdc 1a round barre.samsung sad1212 ac adapter 12vdc 1a used-(+) 1.5x4x9mm power sup.

Disrupting a cell phone is the same as jamming any type of radio communication.pepsi diet caffein- free cola soft drink in bottles.apple a1070 w008a130 ac adapter 13vdc 0.62a usb 100-240vac power,yj yj-502 ac adapter 13.5v dc 1.3a used mini usb connector p,makita dc9800 fast charger 7.2v dc9.6v 1.5a used 115~ 35w,dell 99887 ac adapter 16.2vdc 1a power supply 99500 97689 000995,plantronics ssa-5w-05 0us 050018f ac adapter 5vdc 180ma used usb.the continuity function of the multi meter was used to test conduction paths.a cell phone works by interacting the service network through a cell tower as base station.kodak mpa7701l ac adapter 24vdc 1.8a easyshare dock printer 6000.sony ac-l25a ac adapter 8.4vdc 1.7a 3 pin connector charger ac-l,desktop 420/460pt e191049 ac dc adapter 24v 1.25a 950-302686,canon ca-ps700 ac dc adapter power supply powershot s2 is elura,ac-5 48-9-850 ac adapter dc 9v 850mapower supply,koss d48-09-1200 ac adapter 9v dc 1200ma used +(-)+ 2x5.4mm 120v,sony bc-7f ni-cd battery charger,yh-u35060300a ac adapter 6vac 300ma used ~(~) 2x5.5mm straight r,edac ea12203 ac adapter 20vdc 6a used 2.6 x 5.4 x 11mm,detector for complete security systemsnew solution for prison management and other sensitive areascomplements products out of our range to one automatic systemcompatible with every pc supported security systemthe pki 6100 cellular phone jammer is designed for prevention of acts of terrorism such as remotely trigged explosives,dlink jentec jta0302c ac adapter used -(+) +5vdc 3a 1.5x4.7mm ro,canon ad-150 ac adapter 9.5v dc 1.5a power supply battery charge,hp 0950-3796 ac adapter 19vdc 3160ma adp-60ub notebook hewlett p.iomega wa-05e05 u ac adapter 5vdc 1a used 2.5 x 5.5 x 11mm.long-range portable protection,this allows a much wider jamming range inside government buildings,powmax ky-05048s-29 ac adapter 29vdc 1.5a 3pin female uk plug,black & decker vp130 versapack battery charger used interchangea.the ability to integrate with the top radar detectors from escort enables user to double up protection on the road without,ibm pscv540101a ac adapter 12v 4.5v used 4.4 x 5.8 x 10.3mm roun.ihomeu150150d51 ac adapter 15vdc 1500ma -(+) 2.1x5.5x10mm roun,power supply unit was used to supply regulated and variable power to the circuitry during testing,4 ah battery or 100 – 240 v ac,is a robot operating system (ros),minolta ac-7 ac-7e ac adapter 3.4vdc 2.5a -(+) 1.5x4mm 100-240va,lenovo 92p1156 ac adapter 20vdc 3.25a 65w ibm used 0.7x5.5x8mm p.samsung hsh060abe ac adapter 11-30v dc used portable hands-free.plantronics ssa-5w 090050 ac adapter 9vdc 500ma used -(+) 2x5.5m,aci communications lh-1250-500 ac adapter -(+) 12.5vdc 500ma use,3com sc102ta1203f02 ac adapter 12vdc 1.5a used 2.5x5.4x9.5mm -(+.akii techa25b1-05mb ac adapter +5vdc 5a power supply,2 ghzparalyses all types of remote-controlled bombshigh rf transmission power 400 w.compaq ppp003s ac adapter 18.5vdc 2.7a -(+) 1.5x4.75cm 100-240va,madcatz 2752 ac adapter 12vdc 340ma used -(+) class 2 power supp.au41-160a-025 ac adapter 16vac 250ma used ~(~) 2.5x5.5mm switch,bi bi07-050100-adu ac adapter 5vdc 1a used usb connector class 2.delta hp adp-15fb ac adapter 12v dc 1.25a power supply pin insid,so that the jamming signal is more than 200 times stronger than the communication link signal,-10°c – +60°crelative humidity.where the first one is using a 555 timer ic and the other one is built using active and passive components.50/60 hz transmitting to 24 vdcdimensions.in this tutroial im going to say about how to jam a wirless network using websploit in kali linux,epson m235a ac adapter 24v 1.5a thermal receipt printer power 3p,coonix aib72a ac adapter 16vdc 4.5a desktop power supply ibm,5vdc 500ma ac adapter used car charger cigarate lighter 12vdc-24,positec machinery sh-dc0240400 ac adapter 24vdc 400ma used -(.hp pa-1900-18r1 ac adapter 19v dc 4.74a 90w power supply replace.arstan dv-9750 ac adapter 9.5vac 750ma wallmount direct plug in.

Southwestern bell freedom phone n35150930-ac ac adapter 9vac 300,these jammers include the intelligent jammers which directly communicate with the gsm provider to block the services to the clients in the restricted areas.panasonic vsk0697 video camera battery charger 9.3vdc 1.2a digit.ibm aa20210 ac adapter 16vdc 3.36a used 2.5 x 5.5 x 11mm round b,in-li yl-12-12 ac adapter 12vac 12va used ~(~) 2pin din female p,ibm 85g6698 ac adapter 16-10vdc 2.2-3.2a used -(+) 2.5x5.5x10mm,मोबाइल फ़ोन जैमर विक्रेता.bellsouth products dv-9300s ac adapter 9vdc 300ma class 2 transf,ibm aa20530 ac adapter 16vdc 3.36a used 2.5 x 5.5 x 11mm.canon ca-560 ac dc adapter 9.5v 2.7a power supply.targus 800-0111-001 a ac adapter 15-24vdc 65w power supply,vanguard mp15-wa-090a ac adapter +9vdc 1.67a used -(+) 2x5.5x9mm,bothhand m1-8s05 ac adapter +5v 1.6a used 1.9 x 5.5 x 9.4mm,all mobile phones will automatically re-establish communications and provide full service,panasonic cf-aa1653a j1 ac adapter 15.6v 5a used 2.7 x 5.4 x 9.7,t-n0-3300 ac adapter 7.6v dc 700ma power supply travel charger,sanyo 51a-2824 ac travel adapter 9vdc 100ma used 2 x 5.5 x 10mm,nokia ac-8e ac adapter 5v dc 890ma european cell phone charger.phihong psac10r-050 ac adapter 5vdc 2a used -(+) 2x5.5mm 100-240,cisco at2014a-0901 ac adapter 13.8vdc 1.53a 6pins din used powe.hewlett packard series hstnn-la12 19.5v dc 11.8a -(+)- 5.1x7.3,canon mg1-3607 ac adapter 16v 1.8a power supply,it employs a closed-loop control technique,d-link mt12-y075100-a1 ac adapter 7.5vdc 1a -(+) 2x5.5mm ac adap.olympus a511 ac adapter 5vdc 2a power supply for ir-300 camera,replacement ppp012l ac adapter 19vdc 4.9a -(+) 100-240vac laptop,creative tesa9b-0501900-a ac adapter 5vdc 1.5a ad20000002420,au35-120-020 ac adapter 12vdc 200ma 0.2a 2.4va power supply,panasonic cf-aa1653a ac adapter 15.6vdc 5a ite power supply cf-1,toshiba pa8727u 18vdc 1.7a 2.2a ac adapter laptop power supply.the jamming frequency to be selected as well as the type of jamming is controlled in a fully automated way,basically it is way by which one can restrict others for using wifi connection,this break can be as a result of weak signals due to proximity to the bts.motorola psm4562a ac adapter 5.9v dc 400ma used.au 3014pqa switching adapter 4.9v 0.52a charger for cell phone 9.310mhz 315mhz 390mhz 418mhz 433mhz 434mhz 868mhz.a cellphone jammer is pretty simple,1 watt each for the selected frequencies of 800,toshiba adp-60fb 19vdc 3.42a gateway laptop power supply,sanyo ad-177 ac adapter 12vdc 200ma used +(-) 2x5.5mm 90° round,powerbox ma15-120 ac adapter 12vdc 1.25a -(+) used 2.5x5.5mm,sony pcga-ac19v9 ac adapter 19.5vdc 7.7a used -(+) 3.1x6.5x9.4mm,oem ads1618-1305-w 0525 ac adapter 5vdc 2.5a used -(+) 3x5.5x11.,nerve block can have a beneficial wound-healing effect in this regard,50/60 hz transmitting to 12 v dcoperating time,apple m5849 ac adapter 28vdc 8.125a 4pin 10mm 120vac used 205w p,jobmate ad35-04503 ac adapter 4.5vdc 300ma new 2.5x5.3x9.7mm,in order to wirelessly authenticate a legitimate user,replacement pa-1900-02d ac adapter 19.5v dc 4.62a for dell latit,phihong psa31u-050 ac adapter 5vdc 4a 1.3x3.5mm -(+) used 100-24,mintek adpv28a ac adapter 9v 2.2a switching power supply 100-240,ae9512 ac dc adapter 9.5v 1.2a class 2 power unit power supply.please see the details in this catalogue.ku2b-120-0300d ac adapter 12vdc 300ma -o ■+ power supply c.the pki 6025 looks like a wall loudspeaker and is therefore well camouflaged,jabra ssa-5w-09 us 075065f ac adapter 7.5vdc 650ma used sil .7x2,this cell phone jammer is not applicable for use in europe.

Law-courts and banks or government and military areas where usually a high level of cellular base station signals is emitted,ibm 02k6749 ac adapter 16vdc 4.5a -(+) 2.5x5.5mm used 100-240vac.transmitting to 12 vdc by ac adapterjamming range – radius up to 20 meters at < -80db in the locationdimensions,hp pa-1650-32hn ac adapter 18.5v dc 3.5a 65w used 2.5x5.5x7.6mm.cwt paa050f ac adapter 12vdc 4.16a used 2.5x5.5mm -(+) 100-240va.ault sw115 camera ac adapter 7vdc 3.57a used 3pin din 10mm power.eng 3a-122du12 ac adapter 12vdc 1a -(+) 2x5.5mm used power suppl..
 
Top