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How to Build a Radio / Drone Jammer     Spark gap transmitters are the oldest type of radio transmitter made by man. They were first used around 1888 and remained legal until the 1920s when their use became greatly restricted. World War II delayed their complete ban outside of emergency communications for a few years. Now the only way to use them legally is inside a faraday cage. They operate as jammers for the same reason they were banned, they take up a lot of the radio spectrum. A spark gap transmitter is fairly simple. Send a high voltage current through an air gap, when the resistance of the air breaks down a spark will cross the gap. When this happens electromagnetic radiation is emitted. You can test this in your house fairly easily. Turn on some speakers so they are powered but nothing is coming out of them. Computer speakers that are on will work as will a stereo set to CD or tape with no CD or tape playing. Flip your room lights on and off in rapid succession, you should hear a clicking from the speakers. The clicking is RF energy that is being picked up from the light switch. Effective Range The range of this type of jammer is based on a few properties. Antenna resonance Field strength Modulation Terrain The antenna of this particular device will be more resonant on one frequency than others. As a result there will be more RF energy on that frequency, and harmonics or multiples of that frequency. The range for this frequency will be further than others. Using multiple antennas will cause the transmissions to be greater on more frequencies. The field strength, or amount of RF energy given off, is directly related to the difference in voltage between the two states. With the type of transmitter we are making one state will be totally off or 0 volts while the other will be on or the full voltage. It is not required to switch between an off and on state you may switch between a lower and higher voltage as well. The higher the input voltage the stronger the RF, the more range you will have. You have normal free space losses that all radio transmissions have which means that in order to double the effective range you will have to apply 4 times more power. Another consideration is the modulation that is being utilized. Modulation also includes some of the data that is carried over that mode such as digital data. FM signals for example will lock onto the strongest relative signal from the receivers point of view, a weaker but closer signal will appear stronger than a further but more powerful signal due to free space losses. FM can flip back and forth quickly between two stations that have a nearly equal signal strength at the receivers antenna and make it appear like it is mixing the two stations, the reality is that it is not. SSB will mix the two signals, while you may hear noise in with the desired audio you can still hear the desired audio. Spread spectrum will tolerate the most noise. Digital systems can be jammed even if the underlying modulation is not by introducing noise the decoding circuitry in the radio may not be able to decipher the bits correctly and reconstruct the message. This can result in heavy packet loss on that system rendering it unusable. Many digital systems are more sensitive to noise than their less sophisticated counterparts. Many digital systems are either FM or spread spectrum. FM is more often used for longer range applications. The specific type of system that you are trying to jam is important to know as it will tell you how much power you have to have and at what distance. The best way to determine what is suitable is to get a similar system and see how far it will work from the spark gap transmitter at a given power. Terrain includes buildings, trees and other objects that the radio signals will interact with. If you stash the spark gap transmitter in a metal box the signal will be attenuated compared to that same transmitter being placed in an open field. Elevation can also influence the distance the signal may go. Construction The construction of this type of spark gap generator is fairly simple. You should be able to get everything for under $50 new, used items may be even less expensive. You will need the following items: high voltage source batteries small bit of wood to mount things on small motor a few nails or screws wire The high voltage source could be an automotive ignition coil. This takes the battery or alternator output and makes the voltage much higher so that it will jump across the electrodes of a spark plug igniting the fuel. A spark plug is a spark gap, although it is not suitable in its current form as a radio jammer, it could be made into one. The battery should be suitable to run your high voltage source and the small motor. A motorcycle battery is smaller but will go dead faster than a larger car battery. The wood should be large enough to let you mount the ignition coil, motor and screws on. This can be any scrap wood or similar non-conductive material that you can find. It should be rigid enough that the components will not just fall apart although it does not have to be that strong. It’s purpose is just to hold everything together. A block of cheese or dried mud would work if that is all you have available. The small motor can be anything from a vibrator out of an old pager or mobile phone, an electric fan or one you may find at an electronics or hobby store. It just has to have a shaft that allows mounting of a cross member onto. The first step will be to assemble the motor so that it will function the way you want. When mounting the cross member you should make sure that it is insulated from the rest of the motor either by a plastic shaft or a plastic mounting block. The rod can be a nail although you will want it equidistant from the center.   You can see how the metal rod goes all the way through the plastic insulating block. You may install either one rod all the way through or two rods forming an X. If you install two rods you will have twice the sparks and thus the transmission cycle will be twice as great.   Once the insulating block is mounted on the motor you should affix two other nails or screws on either side so that they almost touch the cross members you installed in the previous step. You do not want them touching but you do want them as close as possible. The closer the better. You should connect the motor to your battery and ensure that it can spin correctly with no problems and that it does not vibrate itself off of the wood. Now prepare your antenna. This is a length of wire cut to 1/4 wavelength of the desired target frequency. If you do not know the target frequency you can just make some guesses. You can also connect multiple antennas together to cover various frequencies. Remember you will have RF emitted on all frequencies it will just be more powerful on the frequencies that the antenna is resonant for. Mobile phones are about 0.5 inch antennas and older police radios are 2.86 inches. For a good spectrum coverage if you make antennas of 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 inches most of the usable spectrum will be covered. Connect the antenna(s) that you made to one of the stationary side rods. To the other end you will need to connect a ground. This can be to a metal water pipe in your house or to a rod driven into the ground. If you do not have a ground the radio will still transmit although it will be at a slightly lower power. Now connect the output of the ignition coil to the stationary rods on either side of the motor. Connect the negative terminal to the ground side and the positive terminal to the side with the antenna(s). The idea here is that when the motor spins current will pass from one rod to the other and out the antenna. The motor will switch the output of the coil on and off in rapid succession. The last and final step is to connect the battery to the motor and the coil. You may optionally install a switch to turn the device on or off or you may just disconnect the battery.

A simple drone Jammer designed to hack unwelcomed civilian drones within your backyard range. What are Jammers?   Commonly Called signal blockers, devices used to block and interfere with radio communication signals What are Civilian (Commercial) Drones?   Also know as unmanned aerial vehicles (UAV), are aircrafts without a human pilot on board. The flight is controlled by the remote control of a pilot on the ground. The typical launch and recovery method of an unmanned aircraft is by the function of an automatic system or an external operator on the ground. There are a wide variety of drones shapes, sizes, configurations, and characteristics. Why Civilian Drone Jammer?   Commercial drones has raised a privacy concerns among United States citizens since most of the drones flies equipped with high quality cameras which can invade people privacy, taking photo of people and personal property. Also drones can be used to smuggle drugs, crash into buildings, act as peeping Toms, drop bombs, shoot guns, and gather personal data on anyone whom drone pilot want to harm. Hence a Jammer to block drones remote control signal to protect our privacy and personal space is required.   Jammer legalization   Jammer which blocks GPS, Cellular communication and/or WIFI are illegal in some countries, so this Jammer design is for educational purposes only and is not for commercial or personal use.   The Design   What to JAM?   In this design we will block the most commonly used remote control R/C communication link by commercial drones’ manufacturer (such as Parrot AR Drones). Common R/C frequencies: Band 1: 2.4 MHz – WIFI g/b/n: ≈ 2.4 – 2.5 GHz Band 2: 433 MHz ISM Band: 433.05-434.79 MHz   Design overview   The design includes two band Jammers (i.e. band 1 & band 2). The RF circuit will consist of voltage controlled oscillator to sweep the required band along with tuning circuit to drive the VCO also it will include a linear power amplifier to amplify the output power of the VCO. Tuning circuit will consist mainly of saw tooth generator to generate the tuning signal along with noise generator to tune the VCO to the required RF Jamming signal. Last but not least power supply circuit is designed to provide the required DC voltages for the RF and the tuning circuits from alternating 220/110 power input.   RF Power requirements   The maximum power of ISM Bands allowed for civilian drone is 36 dBm EIRP (Effective Isotropic Radiated Power) with maximum transmitted power of 1 W (30dBm) and the minimum Signal to Noise ratio SNR is 4 dB for data. Hence using a simple arithmetic; the radiated power of the RF Jammer must be more than 32 dBm EIRP.   To achieve this required radiated power for Band 1 RF circuits, two cascaded power amplifier with total gain of 30 dB is employed with 3dBm VCO output power and 7dBi Antenna; the radiated power of Band 1 RF circuit is 40dBm which exceeds the required Jamming power required to block “band 1 (2.4 GHz)” civilian drone R/C communications.   For Band 2 (433 MHz) RF Circuit; a high gain power amplifier is utilized with 35dB typical gain and 2 dBi Antenna is employed radiating a total EIRP power of 37 dBm which is more than the required Jamming power required to Jam “band 2 (433 MHz) civilian drone R/C communications.   Device Parts   Band 1(2.4 GHz) Jammer RF circuit main parts: The following are the main parts, the rest can be found on the design schematics.   Linear Power Amplifier: Two RFMD RF2317 linear CATV amplifier   IC drones jammer   Voltage Controlled Oscillator (VCO)   CRYSTEKCVCO33BE-2400-2500 VCO which covers the frequencies from 2400 to 2500 MHz Voltage tuning input for the VCO is from 0Vdc to 3Vdc, output power of 3 dBm at 3 Vdc and output Impedance of 50 ohms which is matched to the input impedance of the power amplifier   ANTENNA   7dbi 2.4 GHz Rubber Antenna   Band 2 (433 MHz) Jammer RF Circuit main parts: The following are the main parts, the rest can be found on the design schematics.   Linear Power Amplifier: the Skyworks SKY65116: 390–500 MHz power amplifier. With internal matching impedance to 50 ohms Voltage Controlled Oscillator (VCO): CRYSTEKCVCO33BE-2400-2500 VCO which covers the frequencies from 2400 to 2500 MHz Voltage tuning input for the VCO is from 0Vdc to 3Vdc, output power of 3 dBm at 3 Vdc and output Impedance of 50 ohms which is matched to the input impedance of the power amplifier ANTENNA: 1/4 WAVE WHIP, SMA- right angle, 433MHZ   Tuning Circuits main parts: The following are the main parts, the rest can be found on the design schematics. 555 Timer: To generate square want which will be converted to triangular wave to tune the VCO Zener Diode with power amp: to generate white noise signal   Power Supply Parts: Power supply parts are shown on the design schematic.

Drones Spots on Prison, What does it want to do?   Recently, the Unmanned Aerial Vehicle Drone is seen above several prisons in Fuzhou into the night, and flying in diversion and hovering above the dormitory zone, the teaching building, the administrative building and armed zone. The procuratorate of Fuzhou Gushan District claims that the hovering of unmanned planes above may throw in dangerous articles and film the supervision facilities, which will pose threat on the safety of prison management. But why the unmanned planes / drones are hovering are till unknown.     The UAV or drones can be used in different places. It is usually used to film the landforms, to spy upon some mysterious forbidden places, with outstanding commercial and military value. Therefore, by just raising and seeing the unmanned planes, imagination will fly into people’s head.   However, the public can no longer be calm when they are seen hovering above the prison. The reason is quite simple, the drones will not just hover and do nothing, and the secret will be just kept among the ones concerned. We hold that we must figure it totally out, even though it is just once of hovering. This is because the prison is the place of military limit, where the polices are paying close attention and nothing should happen in here. The unmanned planes are seen several times above the prison, it is quite weird. We couldn’t help but ask, what does the man operating the plane want to do?   The prisons are usually surrounded by polices with strict military management. The area above shall not allow any flying objects. Even though there are no man operating the plane to help the criminals to get out, the drones could film the relevant facilities and obtain some information. Therefore, it cannot be allowed to fly freely above the prison and something should be done to prevent it, or even to ‘get it’. The moment we catch the unmanned plane will we know its purpose right away.   The flying aircraft could not be made and fly by anyone. The air management department should play their duties and enhance the force of supervision. The hovering of unmanned planes above the prison is no good news. The department in charge shall not sit by and do nothing. Only by checking out the source of the unmanned plane and getting the reasonable explanation will the public’s concern be answered and their rights of acquisition be satisfied. The order of an prison shall never ever be intruded by an drone.

It was reported by “First News” of SXBC that the CCTV Spring Festival Evening Gala in Xi’an branch had attracted many aerial photography enthusiasts and the police found there was an unmanned aerial vehicle & drone ignoring the temporary air traffic control measures to interfere the rehearsal on the evening of February 6, and then they used the jammer detector to make it landing. That night, when the rehearsal of Spring Festival Gala in Xi’an branch entered the countdown, the police patrol who are in charge of the security found there was an unmanned aerial vehicle & drone except the CCTV aerial machine in the sky, so they enabled the satellite system satellite system for the querying. Liu Haitao, the police in South Street Police Station of Xi’an Public Security Bureau Beilin Branch, said that the police opened the drone jammer detector by contacting with the municipal public security bureau to make the unmanned aerial vehicle & drone landing, “this aircraft is precisely positioned by satellite, and we controlled the owner after the forced landing of the unmanned aerial vehicle & drone.” The owner of this unmanned aerial vehicle & drone is a man, more than 30 years old, he photographed by controlling the aircraft in a hotel parking lot near the Bell Tower. The owner told the police he is an aircraft enthusiast, at that night, he just felt the Xi’an Southgate is very beautiful recently so he photographed and he never thought that it has interfered the rehearsal of Spring Festival Gala. Liu Haitai said it will not only reveal the contents of the Spring Festival Gala rehearsal, but also interfere in the normal aircraft by taking the liberty of shooting by unmanned aerial vehicle & drone. The police deleted the video shot by the unmanned aerial vehicle & drone in the filed and criticized and educated the owner according to the Law of Public Order Punishment.