1-29. Random-keyed it CW jamming is used against radio facsimile and CW circuits.
Automated equipment cannot distinguish the random dots and dashes from the desired message,
and CW operators may even find it difficult or impossible to read.
A jamming signal that is an unmodulated carrier keyed at random is called a
___________-___________ ___________ signal.
(1-29. Answer: random-keyed CW)
1-30. The keyed CW jamming signal is used primarily against radiotelegraph receivers which
cannot distinguish between the jammed and the desired signal. A jamming signal that is used
against radiotelegraph and transmits actual Morse code characters at the same or faster rate than
the desired signal is known as ___________ jamming.
(1-30. Answer: keyed CW)
1-31. The random-keyed modulated CW jamming signal is very effective against voice
channels. Thus, a random-keyed modulated CW jammed signal is a CW signal keyed at
___________ and then ___________ with spark noise. It is used against ___________ channels.
(1-31. Answer: random, modulated, voice)
1-32. Beat notes with continuous or varying pitch are another type of jamming signal. A
howling sound is produced by varying the pitch of the CW tone and is very disruptive on voice
circuits. A loud, continuous, high-pitched CW tone can also be very irritating to a radio
operator. Varying beat notes that sound like ___________ are very disruptive to ___________
(1-32. Answer: howling, voice)