Modulated Jamming

TM 32-5895-206-10

signal and produces a steady tone in the headset. CW jamming

signals may also be keyed by using a random on-and-off signal

or using actual code characters keyed to the same rate or a little

faster than the signal being received.

b. Modulated Jamming. Modulated jamming signals may

consist of noise, laughter, singing, music, various tones, or most

any unusual sound, or it may be a combination of these sounds.

Various types of modulated jamming signals are explained

below.

(1) Spark. This is one of the simplest, most effective,

and most easily produced jamming signals. This type of signal

sounds very rough, raspy, and sometimes like an operating

electric motor with sparking brushes. The signal is very broad;

therefore it will interfere with a large number of communication

channels.

(2) Sweep-through.

This signal is the result of

sweeping or moving a carrier back and forth across your

frequency at a slow or rapid rate. The numerous signals of

varying amplitude and frequency produce a sound like that of a

low-flying airplane passing overhead. This type of jamming is

effective over a broad range of frequencies. When it is varied

rapidly, it is effective against all types of voice signals.

(3) Stepped tones or bagpipes. This signal usually

consists of several separate tones.

2-74