T2C03 from the Technician License Course Section 2.3, Call Signs:
What should be done to insure that voice message traffic containing proper names and unusual words are copied correctly by the receiving station?
A. The entire message should be repeated at least four times
B. Such messages must be limited to no more than 10 words
C. Such words and terms should be spelled out using a standard phonetic alphabet
D. All of these choices are correct
Receiving and interpreting unusual or infrequently used words and terms can be tricky in some conditions. Same goes for proper names, especially if a non-standard spelling is used. Particularly in an emergency scenario, message traffic must be recorded and passed on with accuracy, exactly as received. With lives and property potentially at risk, precise communication is of paramount concern to the emergency operator.
Poor atmospheric conditions with HF communications, weak signal strength, interference from other stations or emitters, and other environmental factors can degrade the quality of received audio. Even in good conditions many words and alphabetic characters sound very similar. The letters B, C, D, E, G, P, T, V, and Z offer salient examples of similar sounding letters whose differentiation depends strictly upon the beginning phoneme that is commonly comprised of quite high audio frequency components that may not clearly survive the modulation-demodulation process. As this question implies, something must be done to insure voice message traffic is correctly received.
The Response Options:
Option A: Repeating the entire message four times might help, but that is quite inefficient. And in poor conditions it may still not complete the communication correctly.
Option B: Limiting important message traffic to 10 words would not seem to help with interpretation of individual words or letters.
Option C: Now we’re communicating. Spelling out unusual words, terms, or proper names
using a phonetic alphabet works very well to improve communications. So, what is a phonetic alphabet, and particularly a standard phonetic alphabet? (Option D obviously in not applicable given the status of A and B.)
The Rest of the Story:
A phonetic alphabet consists of a word to represent each letter of the alphabet. For instance, ‘A’ is represented by the word ‘Alpha.’ Since words contain more phonemes than letter names, and frequently even multiple syllables, there is redundant audio information transmitted that helps the receiving operator more easily identify or distinguish the letter.
The International Telecommunications Union (ITU) adopted a standard phonetic alphabet in 1959 based upon the preceding phonetic alphabet of the International Civil Aviation Organization (ICAO). These standard phonetics changed and evolved into the adopted standard over the course of a few years following World War II, ensuring their acceptability and uniqueness among international languages.
It is a good idea with international contacts to utilize the ITU standard phonetics rather than alternative phonetics. The international standard phonetic terms are recognizable as such around the world, and they are less likely to be confused for other words or meanings than non-standard phonetics. Using non-standard phonetics can sometimes be confused for other meanings. For instance, I have often heard “Japan” used for ‘J’, “America” for ‘A’, and “Italy” for ‘I’. Usually this does not cause excessive confusion in the proper context, but sometimes these country names may be incorrectly interpreted as the location of the operator. Check out Bob KØNR’s article on phonetics in Shack Talk.
Particularly in noisy single sideband (SSB) phone mode conditions, operators will use phonetics regularly for station identification, for relating operator name, and location. In contest exchanges phonetics are often used to help specify the Maidenhead grid square location of a station for unambiguous and efficient contest exchanges. See and hear examples of this: VHF Contesting Video; Contest Audio
The answer to Technician Class question T2C03, “What should be done to insure that voice message traffic containing proper names and unusual words are copied correctly by the receiving station?” is “C. Such words and terms should be spelled out using a standard phonetic alphabet”
Related Questions: T2B09, T1F04, T2C08