Frank's Ham Radio and Shortwave Radio page

Last update: 29 August 2009

Continuous Wave (CW) is the simplest form of modulation: a carrier wave that is switched ("keyed") on and off. So, actually, CW is not continuous. However, when the carrier wave is "on", it is continuous. This is not the case with spark transmitters that preceded CW transmitters.

CW transmitters are simple, inexpensive, and the transmitted CW signal doesn't occupy much frequency space (usually much less than 500 Hz). However, the CW signals will be difficult to hear on a normal AM receiver; you'll just hear the faint quieting of the background noise as the CW signals are transmitted. To overcome this problem, shortwave and ham radio receivers include a beat frequency oscillator (BFO) circuit. The BFO circuit produces an internally-generated second carrier that "beats" against the received CW signal, producing an audible tone that turns on and off in step with the received CW signal. This is how Morse code signals are received on shortwave.

	Click here and here for a history and background of Morse Code
	Click here for a brief history and explanation of the Q-codes (at least 254 codes in use!)
	Click here for a list of the many other abbreviations used in Morse telegraphy (and other no-voice modes as well)

Tintin/Herge Lotus Bleu Lotus Blue

	Morse code links (DX Zone)
	More CW links
	PA3BWK's "Ultimate Morse Code Web Site"
	"The Art & Skill of Radio-Telegraphy" by William Piermon, NØHFF (SK), 3rd ed., 2002, 241 pp.
	Radio Telegraphy lots of links, history, keys, operations
	"The Telegraph Office" a tribute to Morse telegraphy, and resource for wire and wireless telegraph key collectors and historians
	Click here for "A Beginner's Guide to Making CW Contacts" by WB8FSV

	Click here to hear "the quick brown fox jumps over the lazy dog 1234567890".
	Click here to access W1AW/ARRL Morse code practice files (various speeds, 5-40 wpm)
	Click here for W1AW/ARRL Morese code practice transmission schedules

Morse Code telegraphy