Presentation on Jamming

RADIO JAMMING

Group MembersAbdul Haseeb 1382-FET/BSEE/F-10

Danish Javed 1384-FET/BSEE/F-10

Muhammad Rizwan 1497-FET/BSEE/F-10

Arslan Iqbal 1285-FET/BSEE/F-10

WHAT IS JAMMING?

Jamming is a technique in which a receiver is overloaded with a high power transmission of jamming signal from a transmitter i.e., decrease in S/N ratio.

Note that jammer itself is a transmitter. In theory transmission can be jammed but in most real cases it

is the receiver that is jammed using jamming signal. Jamming is not absolute i.e., once a receiver is jammed there

are still ways from which communication can take place. The technique used to overcome jamming is called ‘burn-

through’. The practical purpose of jamming is to prevent enemy from

using radio link freely.

CONCEPT DIAGRAM

DIFFERENCE BETWEEN INTERFERENCE AND

JAMMING

Interference is unintentional radio noise that causes decrease in S/N ratio.

Jamming is known as intentional radio noise created so that the receiver cannot get a required S/N ratio.

HISTORY

The concept of jamming started theoretically to the dawn of radio communication.

The idea progressed through Cold War era and in various conflicts most importantly Vietnam war and Arab-Israeli wars.

During WW2, in occupied Europe the Nazis attempted to jam broadcasts to the continent from the BBC and other allied stations.

During much of the Cold War Soviet (and Eastern Bloc) jamming of some Western broadcasters led to a "power race“.

METHOD OF JAMMING

Using same frequency.

Same modulation technique.

Power higher than that of original transmitter.

Bluetooth and WiFi can be jammed with very low power.

TYPES OF JAMMING

There are two types of jamming.

Obvious and subtle.

By preventing ‘hand shaking’.

In Bluetooth and consumer radios a channel is kept all time busy to be jammed.

MOBILE PHONE JAMMING

Blocks cell phone use.

Makes phone unusable.

Network appears to be out of range.

Can block phone to tower or tower to phone channels.

Smaller handheld models block all bands from 800 MHz to 1900 MHz within a 30-foot range (9 meters).

PARTS OF JAMMER

Antenna

Circuitry

The main electronic components of a jammer are:

Voltage-controlled oscillator

Tuning circuit

Noise generator

RF amplification (gain stage)

Power supply

PREVENTION TECHNIQUES

Jamming can be avoided using multiple frequencies and changing them randomly.

Jamming can also be prevented by increasing transmitted power, but such a method usually result in a ‘power race’.

The point where transmitter power overcomes the jamming signal is known as burn-through.

APPLICATIONS

Civilian :-Radio station jammingSatellite TV stations jammingInternet jamming (fully or partly)VIP convoy safetyMobile jamming

Military :-Radar JammingCommunication jamming