Now simply called “CW”, radio communication by Morse code was the only way to communicate for the first decade or more of Amateur Radio. Radiotelegraphy, the proper name, descends from landline (wired) telegraphy of the 19th century, and retains some of the old culture, including a rich set of abbreviations and procedures. Morse sent by spark gap transmitter was the first wireless communication mode. These “damped waves” were very broad and inefficient for communication. They were soon replaced by “Continuous Wave” (CW) transmission, using vacuum tube oscillators that were capable of a very pure note. Today, modern Amateur Radio transceivers use solid state components and microprocessors to support a variety of communication modes including CW, voice, image and many digital data modes.

Early radio transmitters could not be modulated to transmit speech, and so CW radio telegraphy was the only form of communication available. CW still remains a viable form of radio communication many years after voice transmission was perfected, because simple, robust transmitters can be used, and because its signals are the simplest of the forms of modulation able to penetrate interference. The low bandwidth of the code signal, due in part to low information transmission rate, allows very selective filters to be used in the receiver, which block out much of the radio noise that would otherwise reduce the intelligibility of the signal.

Continuous-wave radio was called radiotelegraphy because like the telegraph, it worked by means of a simple switch to transmit Morse code. However, instead of controlling the electricity in a cross-country wire, the switch controlled the power sent to a radio transmitter. This mode is still in common use by amateur radio operators.

In military communications and amateur radio the terms “CW” and “Morse code” are often used interchangeably, despite the distinctions between the two. Aside from radio signals, Morse code may be sent using direct current in wires, sound, or light, for example. For radio signals, a carrier wave is keyed on and off to represent the dots and dashes of the code elements. The carrier’s amplitude and frequency remains constant during each code element. At the receiver, the received signal is mixed with a heterodyne signal from a BFO (beat frequency oscillator) to change the radio frequency impulses to sound. Almost all commercial traffic has now ceased operation using Morse, but it is still used by amateur radio operators. Non-directional beacons (NDB) and VHF omnidirectional radio range (VOR) used in air navigation use Morse to transmit their identifier.

Begin to learn Morse Code by starting out with the easiest and simplest letters in the alphabet.

Some of the easiest letters are:

  • E (. or dit)
  • T (- or dah)
  • M (– 0r dah dah)
  • I (.. or dit dit)

These Morse Code letters are the only letters in Morse Code that use one or two dits and dahs and do not combine the dits and dahs.

From there, the next easiest step is to move onto the simple dit and dah combinations, those using only 2 or 3 dits and dahs.

Here are the next Morse Code letters to learn:

  • A (.- or dit dah)
  • D (-.. or dah dit dit)
  • G (–. or dah dah dit)
  • (H) (…. or dit dit dit dit)
  • K (-.- or dah dit dah)
  • N (-. or dah dit)
  • O (— or dah dah dah)
  • R (.-. or dit dah dit)
  • S (… or dit dit dit dit)
  • U (..- or dit dit dah)
  • W (.– or dit dah dah)

Finally, ending with the more difficult letters like “C”, “L”, “Q”, and “X”, that combine 4 dits and dahs in no particular “order”.

Here are the more difficult Morse Code letters:

  • B (-… or dah dit dit dit)
  • C (-.-. or dah dit dah dit)
  • J (.— or dit dah dah dah)
  • L (.-.. or dit dah dit dit)
  • F (..-. or dit dit dah dit)
  • Q (–.- or dah dah dit dah)
  • P (.–. dit dah dah dit)
  • V (…- or dit dit dit dah)
  • X (-..- or dah dit dit dah)
  • Y (-.– or dah dit dah dah)
  • Z (–.. or dah dah dit dit)