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In olden days while we were using analog signal for communication, the jamming circuit was very easy just by producing the high frequency noise signals, but today trend is completely changed in such a way that use of digital devices taken place from analog devices. High-frequency signals are not capable to block those signals from reaching the devices, so we need very high frequency signals to block the actual signals from reaching the devices, so jammers are used for blocking the signals.

Outline

Jammer Circuits:

Jammer circuit produces the high-frequency signal which will confuse the receiver of the particular system from receiving the signal, even though circuit is working properly, user of the system feels that circuit is not working properly. This type of high frequency signal generation through jammer is called noise and the circuit is called jammer because it will mix the main signal with noise signal.

Also Read the Important Post: Mobile Phone Jammer Circuit

Now let us know about simple FM Radio Jammer Circuit and its working.

Note: This circuit diagram has been taken from circuitstoday.com website.

FM Jammer Circuit Explanation:

• The variable capacitor C1 and L1 will constitute the tank circuit which will produce the high frequency signal, the capacitor C1 is variable so that we can produce different frequency signal by adjusting the variable capacitor. When the Q1 is turned ON, the tank circuit will start its operation and produce the VHF signal (very high frequency signal) which will jam or create the noise in the original signal so that receiver cannot receive the signal. Even if it is received also, the signal cannot be used by the receiver circuit.
• The resistors R1 and R2 will act as the biasing circuit and R3 is used for limiting the emitter current in the circuit.

Note:

• This type of circuit is banned in many countries. Use it by your own risk.
• Capacitor C1 value should be changed for every station for getting the different frequency.
• Different frequencies can be achieved by changing the values of capacitor and inductor. The formula is F= 1/ (2*pi*sqrt (L*C)).

Do you know How TV Remote Control Jammer Works?

Applications of Jammer Circuits:

Normally jammers are used in government offices in some countries, but jammers are mainly used by military, navy, air force and entire defense systems. People will not use jammers everywhere, but they use in selected places and highly confidential meetings, gathering etc.

15 Responses

1. prashant kumar says:

what type and range of antenna is required for fm jammer circuit.also provide check list for this project

2. partha says:

can we emit our frequency and block other signals

3. Chris says:

Whats the value for L1?

1. Anusha says:

Value of L1 is 0.5nH…

How to make 0.5nH Inductor

2. Himaja says:

6 turns of 16mm copper wire serves as inductor…

1. yatin patil says:

can u tell me details of L1 in circuit and gauge of copper wire

4. Vaishnavi. says:

How many turns will be required for the inductor?

5. Himaja says:

6 turns of 16mm copper wire serves as inductor l1.. And any wire which is 30 cm long acts as antenna….I did it for my project and it is working….it blocked 101.9 and 102.8MHz radio channels…

6. rufai says:

how does it works

7. yankun says:

can this circuits block all of the fm frequencies?
or just those two frequencies?

8. shilpa says:

what is the value of antenna & inductor

9. shilpa says:

tel me the each component value

10. YASER TAHA says:

what do you mean by the letter Q1

1. Karam says:

Q refer as a Transistor (Q1 for 1st Transistor) and T for transformers, as well as U for ICs.