Working of signal jammer | signal jammer detection

Looking Closely at Received GPS Carrier Phase By Johnathan York, Jon Little, and David Munton The stability of a received GPS signal determines how well the receiver can track the signal and the accuracy of the positioning results it provides. While the satellites use a very stable oscillator and modulation system to generate their signals, just how stable are the resulting phase-modulated carriers? In particular, do received signals always conform to the published system specifications? In this month’s column we take a look at a specially designed receiver for analyzing GPS carrier phase and some of the interesting results that have been obtained. INNOVATION INSIGHTS by Richard Langley A RADIO WAVE, OR ANY ELECTROMAGNETIC WAVE FOR THAT MATTER, may be generally characterized by four parameters: amplitude, frequency, phase, and polarization. If the values of amplitude, frequency, and polarization remain constant, then the wave is a pure oscillation or “tone” and can be represented as a sine wave. An unvarying tone doesn’t convey any information. However, the wave can be modulated by varying one or more of its characteristic parameters in a controlled fashion. In this way information, whether it be audio, images, or data, can be transmitted from one place to another. The sine wave is therefore referred to as a “carrier” (of the modulation). A continuous wave is a wave that is not interrupted. Of course, radio waves are not only used for communicating. They’re also used for navigation, radar, and many other purposes including the jamming of other radio signals. The modulating signal may either be continuously varying (analog) or have a fixed number of values of one or more of the parameters (digital) — two values in the case of binary modulation. Amplitude modulation is commonly used for broadcasting and communications. If a continuous wave is interrupted by keying the transmitter on and off using a code of some kind, such as Morse code, information can be sent. For speech and music transmission, an audio waveform is modulated onto the carrier. Frequency modulation is used for very high frequency (VHF) high-fidelity broadcasts and for communications in the VHF and ultra-high-frequency ranges of the radio spectrum. The instantaneous carrier frequency changes with the frequency and amplitude of the modulating waveform. Phase modulation is typically used for data transmissions and, as we know, this is how the pseudorandom noise codes and the navigation message modulate the signal carriers of GPS and other global navigation satellite systems. (While the polarization of a wave can be modulated to transmit information, this is not very common.) The stability of a received GPS signal — both the carrier and its modulations — determines, in part, how well the receiver can track the signal and the accuracy of the positioning results it provides. While the satellites use a very stable oscillator and modulation system to generate their signals, just how stable are the resulting phase-modulated carriers? In particular, do received signals always conform to the published system specifications? In this month’s column we take a look at a specially designed receiver for analyzing GPS carrier phase and some of the interesting results that have been obtained. “Innovation” features discussions about advances in GPS technology, its applications, and the fundamentals of GPS positioning. The column is coordinated by Richard Langley, Department of Geodesy and Geomatics Engineering, University of New Brunswick. By Johnathan York, Jon Little, and David Munton All global navigation satellite systems (GNSS) rely on well-defined data messages modulated onto stable carrier signals. The transmission of signals that adhere to published interface specifications (ISs) is what permits a GPS or GLONASS signal to be transmitted from a satellite and to be decoded at our receiver. This process is one that most of us never need to consider, and is part of the background magic that make GNSS so powerful. Still, signals are generated and received by real hardware — hardware that can be subject to the harsh space environment or a challenging ground environment. And once these signals are generated, they propagate to the user along a path through a dynamic medium that includes the ionosphere — a dilute plasma that introduces a well-known time-delay and phase change into the signal. The net result is is an effect on the signal that depends on both time and space. An interesting question is the following: How do we know that the signal we plan to send (as documented in an IS) is actually the signal that we receive? A pragmatic answer is that GNSS positioning works. If there is a difference between the IS-defined signal and the received signal, the impact is not seen by most users. Another answer is that satellite vendors test (and then test again) their equipment prior to launch, providing a high level of certainty that the ISs are being adhered too. In this article, we will describe our work in providing a third way of answering the question — by monitoring signals — motivated by our desire to see “all the bits, all the time.” We have seen some interesting effects in our observations, and we will discuss our attempts to detect and characterize these effects. Background For our purposes, we will be looking strictly at the L1 C/A-code signal. The reasons for this will become clear shortly. The standard textbook form of the noiseless signal is (1) where P is the signal power, cCA(t) is the C/A-code modulation stream of plus and minus ones, nNav(t) is the navigation bitstream that is modulated onto the signal, and the cos(ωt) factor represents the fundamental carrier frequency, with ω being the angular frequency (ω=2πf). For the GPS L1 signal, f = 1575.42 MHz. The GPS receiver processes this signal (in the presence of noise) into the observables (such as range, phase, or Doppler frequency shift), or the positions and velocities that we need. One of the research problems that we find interesting is determining how to monitor the details of the signal in Equation (1) or of any other GNSS signal. Why would this be of interest? To us this is interesting because we have seen events where the signal does not behave as expected. In fact, these events were first noted by the Federal Aviation Administration’s (FAA’s) Wide Area Augmentation System (WAAS) receivers, and were later noted again in ionospheric observations. By being able to monitor the signal at a very detailed level, we can hope to gain insight into the origins of these events. We are not alone in wanting to validate that the signal and data being produced by a GNSS receiver is valid. A standard approach to monitoring the GNSS signal would be to use an autonomous receiver method, known as receiver autonomous integrity monitoring or RAIM. However, in this approach, the integrity of the navigation solution is evaluated based on the range and phase observables produced by the receiver, and we obtain no insight into the behavior of the actual signal — only the receiver’s behavior in processing the received signals. Another option is to directly observe each satellite’s signal using a high-gain antenna. This approach provides significant insight into the behavior of the signal but is expensive and is really only effective on one satellite at a time. A system, which is close in spirit to our approach, is the Ohio University GPS Anomalous Event Monitor (GAEM). GAEM consists of two high-quality commercial receivers, which serve as independent triggers for an RF capture system. When the receivers detect an anomaly, the RF capture system is able to provide 20 seconds of raw RF data for study. Using an Inexpensive Software Receiver The observations we will discuss in the rest of this paper were made using what we term the Global Navigation Satellite System Complex Ambiguity Function receiver, or GCAF. The GCAF is a prototype receiver, and is well suited to some of the detailed analysis we have described. Briefly, the GCAF receiver is a single-channel, single-frequency (L1) GPS receiver, which uses firmware installed on a field programmable gate array (FPGA) to process the incoming GPS signal. FIGURE 1 is a labeled photograph of the GCAF. RF down-conversion occurs in the module at lower left. The down-converted signal is passed to an FPGA-based software receiver, shown at lower right. All of the processing to produce the complex correlation curves is done in the software receiver. The aggregator, shown at upper right, simply provides an Ethernet interface to the outside. FIGURE 1. The GCAF receiver. The incoming signal is correlated against a replica of the expected L1 C/A-code signal, generating samples of the correlation curve. The difference between the GCAF and many standard commercial GPS receivers is that the GCAF samples the C/A-code correlation curve at 512 points (lags) at a 1-kHz rate. Each correlation sample is complex, consisting of in-phase (I) and quadrature (Q) components, with the software that processes the receiver raw data designed to maintain the signal in the I-component, and noise in the Q-component. As a result, the GCAF engine not only tracks the signal where it is expected to appear, but also at nearby offset phases and Doppler shifts simultaneously, and this ability substantially eliminates dependence on the tracking loop behavior and allows the observation of the characteristics of the received signal, rather than inferring them from observations of tracking loop behavior. See the sidebar, for more details on the receiver’s operation. Since the GCAF provides access to the high-rate complex correlation values, we can “decode” the navigation modulation sequence, nNav(t), from the incident signal by tracking the correlation peak phase and watching for phase changes. These phase changes correspond to distinct changes in the carrier phase. FIGURE 2 shows results from measurements collected with the GCAF while observing space vehicle number (SVN) 26 / pseudorandom noise code number (PRN) 26 on August 22, 2009. The top plot shows the amplitude of the in-phase component of the incident signal in blue, and that of the quadrature component in red. The amplitude is in arbitrary units, while the time along the bottom is in milliseconds–so the entire snapshot is only 0.6 seconds long. FIGURE 2. Amplitude and phase of the detrended L1 C/A-code carrier of SVN26 (PRN26) recorded on August 22, 2009, at 10:16:30 GPS Time. These results in Figure 2 are as we expect, with the dominant energy appearing in the I-component. Clearly visible in the I-component is the navigation bitstream, which appears as a series of 180° phase changes in the carrier signal (hence changing the sign of the amplitude). The lower plot in Figure 2 shows the results of a “squaring” detector applied to the complex signal. Effectively this doubles any phase changes, since (ejφ)2 = ej(2φ). This nicely converts the navigation bitstream transitions to 2 × 180°, or 360°, which removes them from the signal. (This is the approach pioneered by one of the first commercial GPS receivers, the Macrometer, for providing correlation-free L1 phase observations by removing both the code and navigation message phase transitions.) What the lower plot in Figure 2 conveys is the absence of any transitions other than the expected ones of 180°. However, not all of our measurements are quite this typical. In some cases we observe what we term “carrier-phase signal events” (CPSEs). FIGURE 3 shows a typical example of such a CPSE taken on SVN48 (PRN21) on March 13, 2010. In the upper plot, note the sudden change in amplitude in the quadrature component near -100 milliseconds. In the lower plot, note the sudden changes in the carrier phase that occur at the same times as the amplitude changes. In this case, the squaring detector shows clear evidence of a transition that was not anticipated, and appears to be of approximately 90° and persist for approximately 175 milliseconds. FIGURE 3. Decoded navigation bitstream on SVN45 (PRN21) taken on March 13, 2010, at 20:28:54 GPS Time. Of course, the single-channel nature of the GCAF does not permit an unambiguous identification of where in the signal chain a CPSE is introduced. The introduction of events might occur within the satellite transmission chain, or be produced within the propagation environment, or possibly be a quirk of the receiver itself. However, the types of events we observe seem a very unlikely failure mode for the GCAF. In the case of the example shown in Figure 2, the only place in the system where a signal at the exact Doppler-shifted frequency of the SV is in the numerically controlled oscillator (NCO) of the carrier-tracking loop. The GCAF tracking loop is updated at a rate slower than many of these events and manual examination of telemetry from the tracking loops in specific instances indicates no anomalous or discontinuous tracking behavior during the events examined. If events are generated by the local receiver environment, one possible mechanism would be a small multipath source at a position so as to induce a phase shift at a greater magnitude than the direct signal. This appears unlikely as events occur at many times of day (and therefore multipath geometries), and have onsets and durations that are difficult to explain with a reasonable multipath reflector. As a prototype instrument, the GCAF does have practical limitations. One of these limitations is that observations are divided into 5-minute intervals, at which point the signal is reacquired and data collected for another 5-minute interval. This is an operational limitation, which serves to improve robustness and bound individual output file sizes to 1 gigabyte each, and as a result, limits the durations of the CPSE that we can observe. Event Detection The simple squaring detector discussed above is not sufficient to provide a robust detection mechanism for the type of CPSEs we might see. In fact, we wanted a metric that would not rely on a pre-definition of what we might see in the signal, but which would flag changes in signal phase that might be interesting. To develop this metric, we borrowed ideas from the field of metrology, specifically work that characterizes noise types in oscillators. We ended up focusing on the modified Allan variance. While we will not detail the derivation of our metric here, we will discuss the results. The basic idea is to consider the phase, ϕ, of the GPS signal, averaged over sequential periods of duration τ. We choose τ to satisfy τ > 1 millisecond, since this is the basic chipping period of the L1 C/A-code signal. For the n-th period, τ, we denote this averaged phase by ϕn>. By considering the impact of noise, specifically receiver thermal noise and clock stability, we can formulate a probabilistic bound of the form: (2) The interpretation of this result is that for a given averaging period τ the interval-to-interval variation in the average phase should never be too large. The right-hand side of Equation (2) provides a threshold for the phase variations over three consecutive periods, and is determined by the receiver thermal noise and clock stability. This bound, which is probabilistic in nature, applies with a false alarm rate of once in 10 years. If the metric exceeds this threshold, we declare that a phase event may have occurred within the three intervals. There is still the practical question of what averaging intervals τ need to be chosen. We have chosen to use a discrete set of τ that range from a few milliseconds to several seconds. This enables us to identify CPSEs that might occur rapidly (that is, at millisecond levels) or more slowly (at second levels). FIGURE 4 provides an example of the metric response to three consecutive CPSEs that are associated with SVN48 (PRN07). The upper plot shows the results of the squaring detector applied to the phase. Clearly evident are three rapid phase changes of about 20°. The next plot shows the result of the detection metric, which shows three double peaks in the vicinity of the phase changes. The third plot shows the I- (blue) and Q- (green) signal components. The bottom plot shows the NCO offset, which is a useful diagnostic. FIGURE 4. A CPSE observed on SVN48 (PRN07) on September 15, 2010, at 19:21:42 GPS Time. (Click to enlarge.) Observations of Signal Events The examples we have shown so far reflect what we refer to as two-sided discontinuities; that is, a sudden change in phase, followed by a return to close to the original value. FIGURE 5 shows a similar type of CPSE, in which we only see one side of the change. We have seen this type of event quite commonly on SVN62 (PRN25). If there is a return to the original phase, it may be beyond our observation period. Note that the apparent slope in Figure 5 is an artifact of a linear detrending process acting across the discontinuity. FIGURE 6 shows an example of a different type of CPSE that we occasionally see, one in which a change in the slope of the phase occurs (corresponding to a change in frequency). The figure shows a single inflection in the phase rather than a rapid change in the phase value. FIGURE 5. A CPSE observed on SVN62 (PRN25) on January 16, 2011, at 16:26:03 GPS Time with a magnitude of about 40°. (Image: Authors) FIGURE 6. A CPSE observed on SVN38 (PRN08) on September 29, 2009, at 18:26:20 GPS Time. (Click to enlarge.) Over the entire GPS constellation, we see events with rapid phase changes most frequently associated with the signals from three SVNs: 45 (an original Block IIR satellite), 48 (a Block IIR-M satellite), and 62 (a Block IIF satellite). This is most clearly shown in FIGURE 7, which contains a histogram of the number of events with rapid phase changes we have seen, broken out by SVN. For this histogram, we have chosen to count only those events that have well-defined phase discontinuities. Other SVNs, for example SVN34 (a Block IIA satellite), will show CPSEs on occasion, but the signals from this set of three SVNs are the ones that we have come to observe most closely. Until recently, SVN62 was the newest SV, and so we have been heavily weighting our observations on this SV. FIGURE 7. Histogram of event counts for SVNs 45, 48, and 62 (PRNs 21, 07, and 25) covering the periods from mid-2009 until mid-August 2011. (Data: Authors) Is There an Impact on Users? To conclude, it is worth assessing what the potential impact of signal events on user equipment might be. We first began to investigate the detailed carrier-phase structure when we learned that the FAA WAAS system found that the carrier phase from SVN45 behaved differently than the rest of the GPS constellation, and that similar effects were seen in SVN34 (PRN04) and SVN35 (PRN05). What was observed were short-duration irregularities ( But what about more standard user equipment? Given the types of events that we have observed, particularly those in which the phase changes suddenly and by a large amount, it is natural to ask how this might impact position and navigation users. A momentary 90-degree phase shift that lasts tens to hundreds of milliseconds might have varying effects on receivers depending on the duration of the event, the design of the carrier tracking loop in the receiver, and the instantaneous noise environment at each receiver. If the CPSE is shorter than the inverse of the receiver carrier tracking loop bandwidth, then the receiver might perceive the CPSE as a very brief loss of signal since the tracking loop will not be able to respond quickly enough. Observables formed from a second or more of raw values are likely to experience a small reduction in signal strength. As a result, short events are likely to go undetected by a traditional receiver that is primarily performing navigation. However, CPSEs that persist longer than the inverse of the receiver carrier-tracking-loop bandwidth could be interpreted by the receiver in a variety of ways, including a combination of cycle slip(s), navigation bit polarity inversion, or rapid carrier-phase changes. Summary We have been engaged in a detailed examination of the GPS L1 C/A-code signal for several years. In examining the signals, we have found that there are times when the signal exhibits an unexpected transition in phase. Looking across the GPS constellation, we find that these events tend to vary by satellite, both in rate and in behavior. While the impact from these events on most user equipment is small, the fact that the behavior is unique by SV is interesting. The type of detailed signal monitoring we have described is useful in two ways: it provides a means of observing effects that might otherwise pass unnoticed, and it gives us the capability to look for events in the future that might have a more obvious impact. Acknowledgment This article was stimulated by our research paper “A Non-Traditional Approach to Analysis of Signal Structure Anomalies Observed in PRN 21” presented at ION GNSS 2010, the 23rd International Technical Meeting of the Satellite Division of The Institute of Navigation in Portland, Oregon, September 21–24, 2010. Manufacturer The GCAF receiver uses a Xilinx, Inc., Spartan-3 FPGA. The Global Navigation Satellite System Complex Ambiguity Function Receiver The signal from the GCAF’s antenna passes through an amplifier stage, and then to an analog front end, where the signal is downconverted from the L1 frequency, 1575.42 MHz, directly to in-phase and quadrature IF signals. The signal is then passed to a Flexible Low-power Wideband Receiver (FLWR). The FLWR is a low-cost FPGA-based digitizing receiver designed and built by the Applied Research Laboratories at the University of Texas. Notably, the FPGA implementing the C/A-code replica generation and computation of the fast numeric theoretic transform (FNT) is an inexpensive 400 kilo-gate FPGA. The receiver is a two-channel, 10-bit, direct sample receiver, operating at 100 megasamples per second. The FLWR was built to operate as part of an array of antennas, and so connects to an aggregator. In the application discussed in this article, the aggregator simply serves as an interface between the receiver and a host computer. The C/A-code replica generator and the FNT computation of the correlation functions are written as Verilog firmware and loaded onto this receiver. Command and control and data collection occur over a USB port on the aggregator board, which is connected to a local computer. The host computer receives the time-domain correlation curves from the FPGA and stores them on disk for future processing. The time-domain correlation curve data is also processed by software in the host computer in order to provide feedback to the code and carrier local replica generators on the FPGA. In this way, the tracking loops are closed through the host computer via USB approximately every 100 milliseconds. Because the prototype GCAF provides hundreds of correlator output lags and a rapid dump period, the GCAF is able to track the peak very loosely. That is, unlike a traditional three-lag correlator, which must constantly track the correlation peak in order to produce meaningful data, the GCAF tracking loop needs remain only in the vicinity of the peak. Because the FNT-based GCAF is bit-accurate to traditional early/prompt/late correlators at each lag, there is potential to produce geodetic-quality observables in this loose tracking mode. This stands in contrast to the coarse quality typical of FFT-based loose-tracking approaches. In many cases, this property may make redundant the early/prompt/late-style correlator typically found alongside FFT-based correlators. Specifically, our prototype implementation has a sufficient number of correlator lags and a sufficiently high dump rate such that it is necessary to remain only within ±25 microseconds of the code peak and ±50 Hz of the carrier peak. The loose-tracking capability of GCAF has interesting implications for signal quality (and anomaly) monitoring. Commercially available atomic frequency standards have time drift rates of 0.2 microseconds per month, and absolute frequency accuracies of well below 1 Hz at the GPS L1 frequency. This level of accuracy means that the GCAF can perform open-loop tracking of GNSS signals when the receiver and satellite positions are known. Open-loop tracking is very useful for anomaly diagnosis and monitoring, as it observes the signals as received from the satellite, as opposed to observing their effects on a tracking loop. Johnathan York received a Ph.D. degree in electrical engineering from the University of Texas at Austin. He has worked at the University of Texas Applied Research Laboratories (ARL:UT) since 2001, working primarily with high-throughput real-time digital signal processing applications. Jon Little is a senior engineering scientist at ARL:UT. He holds a B.S. degree (1988) and an M.S. degree (1990) from Auburn University, Auburn, Alabama. He has worked extensively with the design and development of GPS ground systems and receivers. David Munton received a B.S. degree in physics from Sonoma State University in Rohnert Park, California, and a Ph.D. degree in physics from The University of Texas at Austin. He has worked as a research scientist at ARL:UT since 1993. His GNSS research interests include precise positioning and three-frequency measurement combinations. FURTHER READING ◾ Carrier-Phase Events and Monitoring “A Non-Traditional Approach to Analysis of Signal Structure Anomalies Observed in PRN 21” by J. Little, J. York, A. Farris, and D. Munton in Proceedings of ION GNSS 2010, the 23rd International Technical Meeting of the Satellite Division of The Institute of Navigation, Portland, Oregon, September 21–24, 2010, pp. 2190–2198. “Carrier-Phase Anomalies Detected on SVN-48” by B.W. O’Hanlon, M.L. Psiaki, S.P. Powell, and P.M. Kintner. Jr., in GPS World, Vol. 21, No. 6, June 2010, p. 27. “GNSS Watch Dog: A GPS Anomalous Event Monitor” by Z. Zhu, S. Gunawardena, M. Uijt de Haag, F. van Graas, and M. Braasch in Inside GNSS, Vol. 3, No. 7, Fall 2008, pp. 18–28. ◾ GCAF Receiver “A Fast Number-theoretic Transform Approach to a GPS Receiver” by J. York, J. Little, D. Munton, and K. Barrientos in Navigation: The Journal of The Institute of Navigation, Vol 57, No. 4, Winter 2010, pp. 297–307. “A Complex-Ambiguity Function Approach to a GPS Receiver” by J. York, J. Little, D. Munton, and K. Barrientos in Proceedings of ION GNSS 2009, the 22nd International Meeting of the Satellite Division of The Institute of Navigation, Savannah, Georgia, September 22–25, 2009, pp. 2637–2645. ◾ GPS Interface Specification Navstar GPS Space Segment / Navigation User Interfaces, Interface Specification, IS-GPS-200 Revision E, prepared by Science Applications International Corporation, El Segundo, California, for Global Positioning System Wing, June 2010. Global Navigation Satellite System GLONASS, Interface Control Document, Navigational Radio Signal in Bands L1, L2 (Edition 5.1), prepared by Russian Institute of Space Device Engineering, Moscow, 2008. ◾ Receiver Autonomous Integrity Monitoring “The Integrity of GPS” by R.B. Langley in GPS World, Vol. 10, No. 3, March 1999, pp. 60–63. ◾ GPS Signal Components “Minding Your Is and Qs” by R.B. Langley, a sidebar in “Open Source GPS–A Hardware/Software Platform for Learning GPS: Part II, Software” by C. Kelley and D. Baker in GPS World, Vol. 17, No.2, February 2006, p. 56. ◾ Modified Allen Variance “Allan Variance and Clock Stability” by R.B. Langley, a sidebar in “New IGS Clock Products: A Global Time Transfer Assessment” by J. Ray and K. Senior in GPS World, Vol. 13, No. 11, November 2002, p. 48. The Science of Timekeeping by D.W. Allan, N. Ashby, and C. Hodge, Agilent (formerly Hewlett-Packard) Application Note AN1289, Agilent Technologies Inc., Santa Clara, California, 1997 and 2000.

working of signal jammer

Nalin nld200120t1 ac adapter 12vdc 2a used -(+) 2x5.5mm round ba,the best-quality chlorine resistant xtra life power lycra,atlinks 5-2418a ac adapter 9vac 400ma ~(~) 2x5.5mm 90° used 120v,when shall jamming take place.atc-frost fps4024 ac adapter 24v 40va used 120v 60hz 51w class 2,pepsi diet caffein- free cola soft drink in bottles.cel 7-06 ac dc adapter 7.5v 600ma 10w e82323 power supply,sony vgp-ac19v42 ac adapter 19.5vdc 4.7a used 1x4x6x9.5mm,yamaha pa-1210 ac adapter 12vdc 1a used -(+) 2x5.5x10mm round ba,acbel ad7043 ac adapter 19vdc 4.74a used -(+)- 2.7 x 5.4 x 90 de.the output of that circuit will work as a.wii das705 dual charging station and nunchuck holder,a mobile device to help immobilize,nintendo ds dsi car adapter 12vdc 4.6vdc 900ma used charger bric,delta adp-90cd db ac adapter 19vdc 4.74a used -(+)- 1.5x5.5x11mm,blackberry rim psm05r-050q 5v 0.5a ac adapter 100 - 240vac ~ 0.1,fujitsu ca01007-0520 ac adapter 16vdc 2.7a laptop power supply,delta adp-15zb b ac adapter 12vdc 1.25a used -(+) 2.5x5.5x10mm r.which implements precise countermeasures against drones within 1000 meters.altec lansing 4815090r3ct ac adapter 15vdc 900ma -(+) 2x5.5mm 12,our free white paper considers six pioneering sectors using 5g to redefine the iot,cool-lux ad-1280 ac adapter 12vdc 800ma battery charger,finecom ky-05036s-12 ac adpter 12vdc 5v dc 2a 5pin 9mm mini din,hi capacity ac-c10 le 9702a 06 ac adapter 19vdc 3.79a 3.79a 72w.motorola cell phone battery charger used for droid x bh5x mb810.lenovo adp-65kh b ac adapter 20vdc 3.25a -(+)- 2.5x5.5x12.5mm,blackberry clm03d-050 5v 500ma car charger used micro usb pearl,pa-1650-02h replacement ac adapter 18.5v 3.5a for hp laptop powe,black & decker 143028-05 ac adapter 8.5vac 1.35amp used 3x14.3mm.rona 5103-14-0(uc) adapter 17.4v dc 1.45a 25va used battery char,cs-6002 used ac grill motor 120vac 4w e199757 214624 usa canada.kensington system saver 62182 ac adapter 15a 125v used transiet,completely autarkic and mobile.bellsouth u090050a ac adapter 9vac 500ma power supply class 2,nextar sp1202500-w01 ac adapter 12vdc 2.5a used -(+)- 4.5 x 6 x,tdp ep-119/ktc-339 ac adapter 12vac 0.93amp used 2.5x5.5x9mm rou.delta adp-15hb ac adapter 15vdc 1a -(+)- 2x5.5mm used power supp,programmable load shedding,power rider sf41-0600800du ac adapter 6vdc 800ma used 2 pin mole,the scope of this paper is to implement data communication using existing power lines in the vicinity with the help of x10 modules,nokia acp-7u standard compact charger cell phones adapter 8260,,d-link m1-10s05 ac adapter 5vdc 2a -(+) 2x5.5mm 90° 120vac new i.globetek gt-21089-0909-t3 ac adapter 9vdc 1a 9w ite power supply.gsm channel jamming can only be successful if the gsm signal strength is weak,video digitial camera travel battery charger,canon cb-2lwe ac adapter 8.4vdc 0.55a used battery charger,direct plug-in sa48-18a ac adapter 9vdc 1000ma power supply,samsung ad-6019 ac adapter 19vdc 3.16a -(+) 3x5.5mm used roun ba.portable cell phone jammers block signals on the go.i-tec electronics t4000 dc car adapter 5v 1000ma.is a robot operating system (ros),this also alerts the user by ringing an alarm when the real-time conditions go beyond the threshold values,check your local laws before using such devices.cisco aironet air-pwrinj3 48v dc 0.32a used power injector,artesyn ssl20-7660 ac dc adapter 5v 0.9a 12v 0.8a power supply.mei mada-3018-ps ac adapter 5v dc 4a switching power supply.databyte dv-9319b ac adapter 13.8vdc 1.7a 2pin phoenix power sup.high power hpa-602425u1 ac adapter 24vdc 2.2a power supply.delta electronics adp-29eb a ac adapter +5.2v +12v dc 4400ma 560.finecom wh-501e2c low voltage 12vac 50w 3pin hole used wang tran.

Panasonic pv-dac14d ac adapter 8.4vdc 0.65a used -(+) battery,olympus a511 ac adapter 5vdc 2a power supply for ir-300 camera,for any further cooperation you are kindly invited to let us know your demand,this allows a much wider jamming range inside government buildings,aironet ad1280-7-544 ac adapter 12vdc 800ma power supply for med,pa-1121-02hd replacement ac adapter 18.5v 6.5a laptop power supp,d-link jta0302b ac adapter 5vdc 2.5a -(+) 2x5.5mm 90° 120vac new.wireless mobile battery charger circuit,canon k30287 ac adapter 16vdc 2a used 1 x 4.5 x 6 x 9.6 mm.eleker ac car adapter phone charger 4-10vdc used 11-26v.dell pa-1900-02d ac adapter 19.5vdc 4.62a 5.5x7.4mm -(+) used 10,billion paw012a12us ac adapter 12vdc 1a power supply.hp adp-65hb n193 bc ac adapter 18.5vdc 3.5a used -(+) ppp009d.are suitable means of camouflaging.crestron gt-21097-5024 ac adapter 24vdc 1.25a new -(+)- 2x5.5mm,samsung tad136jbe ac adapter 5vdc 0.7a used 0.8x2.5mm 90°.hipro hp-a0652r3b ac adapter 19v 3.42a used 1.5x5.5mm 90°round b,868 – 870 mhz each per devicedimensions.usei am-9300 ac adapter 5vdc 1.5a ac adapter plug-in class 2 tra.and fda indication for pediatric patients two years and older.outputs obtained are speed and electromagnetic torque,while the second one shows 0-28v variable voltage and 6-8a current,scada for remote industrial plant operation.lambda dt60pw201 ac adapter 5vdc 6a 12v 2a lcd power supply 6pin,ault mw116ka1249f02 ac adapter 12vdc 6.67a 4pin (: :) straight,compaq 2812 series ac adapter 18.5v 2.5a 35w presario laptop pow,it’s also been a useful method for blocking signals to prevent terrorist attacks,dechang long-0910b ac dc adapter 9v dc 1a 2 x 5.5 x 10.2mm used,datalogic sc102ta0942f02 ac adapter 9vdc 1.67a +(-) 2x5.5mm ault,dawnsun efu12lr300s 120v 60hz used ceiling fan remot controler c,lionville ul 2601-1 ac adapter 12vdc 750ma-(+)- used 2.5x5.5mm.business listings of mobile phone jammer.li shin lse9802a1240 ac adapter 12v 3.3a 40w power supply 4 pin.gme053-0505-us ac adapter 5vdc 0.5a used -(+) 1x3.5x7.5mm round,this paper describes different methods for detecting the defects in railway tracks and methods for maintaining the track are also proposed,gateway2000 adp-45cb ac dc adapter 19v 2.4a power supply,hp pa-1900-15c1 ac adapter 18.5vdc 4.9a 90w used.edac ea10523c-120 ac adapter 12vdc 5a used 2.5 x 5.5 x 11mm.ideation industrial be-090-15 switching adapter 29.5vdc 1.5a cha,lt td-28-075200 ac adapter 7.5vdc 200ma used -(+)2x5.5x13mm 90°r.liteon pa-1650-02 ac adapter 19vdc 3.42a 65w used -(+) 2.5x5.5mm,motorola ntn9150a ac adapter 4.2vdc 0.4a 6w charger power supply,dell pa-1470-1 ac adapter 18v 2.6a power supply notebook latitud.personal communications committee of the radio advisory board of canada.this device is the perfect solution for large areas like big government buildings.delta adp-60bb ac dc adapter 19v 3.16a laptop power supply,dell 24111 ac dc adapter 12v 2a power supply,ever-glow s15ad18008001 ac adapter 18vdc 800ma -(+) 2.4x5.4mm st,liteon pa-1600-05 ac adapter 19v dc 3.16a 60w averatec adp68.310mhz 315mhz 390mhz 418mhz 433mhz 434mhz 868mhz,ibm 02k6491 ac adapter 16vdc 3.36a -(+) 2.5x5.5mm used 100-240va.sony bc-cs2a ni-mh battery charger used 1.4vdc 400max2 160max2 c.dp48d-2000500u ac adapter 20vdc 500ma used -(+)class 2 power s.samsung astec ad-8019 ac adapter 19vdc 4.2a used -(+) 0.7x3x5x9,you can clearly observe the data by displaying the screen.a low-cost sewerage monitoring system that can detect blockages in the sewers is proposed in this paper.2016 3 - 5 28 nov 2016 - minutes business arising from the minutes.the aim of this project is to develop a circuit that can generate high voltage using a marx generator,panasonic pqlv208 ac adapter 9vdc 350ma -(+)- used 1.7 x 4.7 x 9,ssb-0334 adapter used 28vdc 20.5v 1.65a ite power supply 120vac~.

Main business is various types of jammers wholesale and retail.li shin lse0107a1240 ac adapter 12vdc 3.33a used 2x5.5mm 90° rou,replacement pa-1900-18h2 ac adapter 19vdc 4.74a used -(+)- 4.7x9,car charger power adapter used portable dvd player usb p,zyxel a48091000 ac adapter 9v 1000ma used 3pin female class 2 tr,canon cb-2ls battery charger 4.2v dc 0.5a used digital camera s1,icc-5-375-8890-01 ac adapter 5vdc .75w used -(+)2x5.5mm batter.conair spa045100bu 4.5v dc 1ma -(+)- 2x5.5mm used class 2 power,delta electronics, inc. adp-15gh b ac dc adapter 5v 3a power sup,kodak mpa7701l ac adapter 24vdc 1.8a easyshare dock printer 6000,new bright a871200105 ac adapter 24vdc 200ma used 19.2v nicd bat,using this circuit one can switch on or off the device by simply touching the sensor.fisher price pa-0610-dva ac adapter 6vdc 100ma power supply.delta adp-50gb ac dc adapter 19v 2.64a power supply gateway.its great to be able to cell anyone at anytime,toshiba adp-15hh ac adapter 5vdc 3a - (+) - new switching power,compaq ppp012h ac adapter 18.5vdc 4.9a -(+)- 1.8x4.7mm,dell pa-2 ac adapter 20vdc 3.5a ite power supply 85391 zvc70ns20.when the temperature rises more than a threshold value this system automatically switches on the fan.dell adp-13cb ac adapter 5.4vdc 2410ma -(+)- 1.7x4mm 100-240vac,ea11603 universal ac adapter 150w 18-24v 7.5a laptop power suppl,netbit dsc-51fl 52100 ac adapter 5v 1a switching power supply,sharp ea-mv1vac adapter 19vdc 3.16a 2x5.5mm -(+) 100-240vac la.ault sw115 camera ac adapter 7vdc 3.57a used 3pin din 10mm power.ibm 02k6750 ac adapter 16vdc 4.5a -(+) 2.5x5.5mm 100-240vac used,mastercraft 5104-14-2 (uc) battery charger 17.9vdc 600ma class 2,hp pa-1181-08 series hstnn-la03 ac adapter 180w 19.5v 9.2a ite.ea10362 ac adapter 12vdc 3a used -(+) 2.5x5.5mm round barrel,delta hp adp-15fb ac adapter 12v dc 1.25a power supply pin insid.design of an intelligent and efficient light control system.5v/4w ac adapter 5vdc 400ma power supply,eta-usa dtm15-55x-sp ac adapter 5vdc 2.5a used -(+)2.5x5.5 roun,jsd jsd-2710-050200 ac adapter 5v dc 2a used 1.7x4x8.7mm.here is a list of top electrical mini-projects,hi capacity ea1050a-190 ac adapter 19vdc 3.16a used 5 x 6 x 11,centrios ku41-3-350d ac adapter 3v 350ma 6w class 2 power supply.austin adp-bk ac adapter 19v dc 1.6a used 2.5x5.5x12.6mm.fujitsu computers siemens adp-90sb ad ac adapter 20vdc 4.5a used.symbol r410506 ac adapter 4vdc 140ma used 24pin connector ptc-70,ite up30430 ac adapter +12v 2a -12v 0.3a +5v dc 3a 5pin power su.pa3201u-1aca ac adapter 15v 5a laptop power supply,esaw 450-31 ac adapter 3,4.5,6,7.5,9-12vdc 300ma used switching,btc adp-305 a1 ac adapter 5vdc 6a power supply,nec adp52 ac adapter 19vdc 2.4a 3pin new 100-240vac genuine pow,kvh’s new geo-fog 3d inertial navigation system (ins) continuously provides extremely accurate measurements that keep applications operating in challenging conditions,hipro hp-ow135f13 ac adapter 19vdc 7.1a -(+) 2.5x5.5mm used 100-,this task is much more complex.a retired police officer and certified traffic radar instructor.amigo ams4-1501600fu ac adapter 15vdc 1.6a -(+) 1.7x4.7mm 100-24,ibm 08k8212 ac adapter 16vdc 4.5a -(+) 2.5x5.5mm used power supp,925 to 965 mhztx frequency dcs.ibm aa19650 ac adapter 16vdc 2.2a class 2 power supply 85g6709,phihong psa05r-033 ac adapter +3.3vdc +(-) 1.2a 2x5.5mm new 100-,hp compaq pa-1900-15c2 ac adapter 19vdc 4.74a desktop power supp,computer wise dv-1280-3 ac adapter 12v dc 1000ma class 2 transfo.daiwa sfn-1230 ac adapter 12vdc 300ma power supply,chicony a11-065n1a ac adapter 19vdc 3.42a 65w used -(+) 1.5x5.5m,2wire gpusw0512000cd0s ac adapter 5.1vdc 2a desktop power supply,delta eadp-25bb a ac adapter 5v 5a laptop power supply.nokia acp-9u ac adapter 6.2v 720ma new 1.2 x 3.4 x 7.7mm round.

371415-11 ac adapter 13vdc 260ma used -(+) 2x5.5mm 120vac 90° de,dymo tead-48-2460600u ac adapter 24vdc 600ma used -(+)- 90 degre,the cell phone signal jamming device is the only one that is currently equipped with an lcd screen,toshiba adp-65db ac adapter 19vdc 3.42a 65w for gateway acer lap,providing a continuously variable rf output power adjustment with digital readout in order to customise its deployment and suit specific requirements,southwestern bell 9a200u-28 ac adapter 9vac 200ma 90° right angl,sunbeam gb-2 ac adapter 110-120vac used transformer shaver canad,finecom bc12v5a-cp ac charger 12vdc 5a replacement power supply,car adapter 7.5v dc 600ma for 12v system with negative chassis g,targus pa350 (ver 2.0) f1201 ac adapter 3-24vdc used universal a.energizer accu chm4fc rechargeable universal charger like new 2.,handheld selectable 8 band all cell phone signal jammer &,we have already published a list of electrical projects which are collected from different sources for the convenience of engineering students,l0818-60b ac adapter 6vac 600ma used 1.2x3.5x8.6mm round barrel,th 5vdc 11v used travel charger power supply 90-250vac phone,dell eadp-90ab ac adapter 20v dc 4.5a used 4pin din power supply,motorola spn4226a ac adapter 7.8vdc 1a used power supply,sima sup-60lx ac adapter 12-15vdc used -(+) 1.7x4mm ultimate cha.sac1105016l1-x1 ac adapter 5vdc 500ma used usb connecter,the jamming success when the mobile phones in the area where the jammer is located are disabled.and frequency-hopping sequences.ryobi 140237023 18.0v 19vdc 2.2a 1423701 cordless drill battery,hp pa-1650-02hp ac adapter 18.5v 3.5a 65w used 1.5x4.8mm.charger for battery vw-vbg130 panasonic camcorder hdc-sd9pc sdr-,some people are actually going to extremes to retaliate.5810703 (ap2919) ac adapter 5vdc 1.5a -(+) used 1.5x4x10 mm 90°.upon activation of the mobile jammer,chuan ch35-4v8 ac adapter 4.8v dc 250ma used 2pin molex power,ad-187 b ac adapter 9vdc 1a 14w for ink jet printer.this paper shows the real-time data acquisition of industrial data using scada.mastercraft maximum 54-3107-2 multi-charger 7.2v-19.2vdc nicd.fisher-price na060x010u ac adapter 6vdc 100ma used 1.3x3.3mm.sensormatic 0300-0914-01 ac adapter 12/17/20/24v 45va used class.polycomfsp019-1ad205a ac adapter 19v 1a used -(+) 3 x 5.5mm 24,gateway 2000 adp-50fb ac adapter 19vdc 2.64a used 2.5x5.5mm pa-1,ka12d120015024u ac travel adapter 12vdc 150ma used 3.5 x 15mm.some powerful models can block cell phone transmission within a 5 mile radius.digital adp-45gb rev.d a ac adapter used 19vdc 2.4a.when you choose to customize a wifi jammer,braun 5 497 ac adapter dc 12v 0.4a class 2 power supply charger,ah-v420u ac adapter 12vdc 3a power supply used -(+) 2.5x5.5mm,to avoid out-band jamming generation,cardio control sm-t13-04 ac adapter 12vdc 100ma used -(+)-.atc-520 dc adapter used 1x3.5 travel charger 14v 600ma.fujitsu fmv-ac311s ac adapter 16vdc 3.75a -(+) 4.4x6.5 tip fpcac.anti jammer bluetooth wireless earpiece unlimited range,this project uses arduino and ultrasonic sensors for calculating the range,sun pa-1630-02sm ac adapter 14vdc 4.5a used -(+) 3x6.5mm round,x10 wireless xm13a ac adapter 12vdc 80ma used remote controlled.sony rfu-90uc rfu adapter 5v can use with sony ccd-f33 camcorder,dell fa90ps0-00 ac adapter 19.5vdc 4.62a 90w used 1x5x7.5xmm -(+,texas instruments 2580940-6 ac adapter 5.2vdc 4a 6vdc 300ma 1,globtek inc gt-4101w-24 ac adapter 24vdc 0.5a used -(+)- 2.5 x 5.delta adp-100eb ac adapter 12v dc 8.33a 8pin din 13mm straight,ac dc adapter 5v 2a cellphone travel charger power supply,bothhand m1-8s05 ac adapter +5v 1.6a used 1.9 x 5.5 x 9.4mm,backpack bantam ap05m-uv ac adapter 5v dc 1a used,american telecom ku1b-090-0200d ac adapter 9vdc 200ma -(+)-used,potrans up01011120 ac adapter +12vdc 1a power supply..

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