What are different types of jam?

Answer 1

Intentional communications jamming is usually aimed at radio signals to disrupt control of a battle.

A transmitter, tuned to the same frequency as the opponents' receiving equipment and with the same type of modulation, can, with enough

power, override any signal at the receiver.

The most common types of this form of signal jamming are

random noise

random pulse

stepped tones

warbler

random keyed modulated CW

tone

rotary

pulse

spark

recorded sounds

gulls

sweep-through.

These can be divided into two groups - obvious and subtle.

Obvious jamming is easy to detect because it can be heard on the receiving equipment.

It usually is some type of noise such as

stepped tones (Bagpipes)

random-keyed code

pulses,

music (often distorted)

erratically warbling tones

highly distorted speech

random noise (hiss) and recorded sounds

Various combinations of these methods may be used often accompanied by regular Morse identification signal to enable individual transmitters

to be identified in order to assess their effectiveness. For example, China, which used jamming extensively and still does, plays a loop of

traditional Chinese music while it is jamming channels.

The purpose of this type of jamming is to block out reception of transmitted signals and to cause a nuisance to the receiving operator. One

early Soviet attempt at jamming western broadcasters used the noise from the diesel generator that was powering the jamming transmitter.

Subtle jamming is jamming during which no sound is heard on the receiving equipment. The radio does not receive incoming signals yet

everything seems superficially normal to the operator. These are often technical attacks on modern equipment, such as "squelch capture".

Thanks to FM capture effect, Frequency Modulated broadcasts may be jammed, unnoticed, by a simple unmodulated carrier