How should 121.1 be spoken on the radio?

• A. One two one decimal one
• B. One twenty one point one
• C. One two one one one
• D. One two one point one

Answer: (D)

In aviation radiotelephony, numbers are spoken digit by digit to avoid mishearing, and the decimal point is spoken as “point.” So a frequency like 121.1 is pronounced as “one two one point one.” This is the clearest, most unambiguous way to convey the digits in a noisy radio environment.

Saying it as “one twenty one point one” would group the first three digits into a single number, which can lead to confusion, and using the word “decimal” isn’t the standard term used in phraseology. Reading all digits after the point as separate digits without marking the decimal would also be misleading.