Allied Communications Procedure 125(F), Communication Instructions Radiotelephone Procedure, published by the Combined Communication Electronics Board, defines radiotelephone procedures, and contains the original definitions for many common radio communications procedures, including Procedure Words, radio net operations, etc. Section 611 of ACP(F) details how to conduct radio checks using plain language.
Contents
Radio Check Procedure
The prowords listed below are for use when initiating and answering queries concerning signal strength and readability.
Usage
One of these reports, "LOUD AND CLEAR", is commonly used in television shows, movies, literature, and by radio operators, commonly without knowing the source or the rest of the standard reports (hence the much-reduced frequency with which the other combinations are used). For example:
LOUD CLEAR means Excellent copy with no noise
GOOD READABLE means Good copy with slight noise
FAIR READABLE means Fair copy, occasional fills are needed
WEAK READABLE means Weak copy, frequent fills are needed
WEAK UNREADABLE means Unable to copy, a relay is required
Current or former military radio operators may sometimes use ITU phonetics instead of the plain language, as in "I copy Lima Charlie" instead of "LOUD AND CLEAR".
A station is understood to have good signal strength and readability unless otherwise notified. Strength of signals and readability will not be exchanged unless one station cannot clearly hear another station.
A station that wishes to inform another of his signal strength and readability will do so by means of a short and concise report of actual reception such as, WEAK BUT READABLE, LOUD BUT DISTORTED, WEAK WITH INTERFERENCE, etc. Reports such as “five by five,” “four by four,” etc., will not be used to indicate strength and quality of reception.
The omission of comment on signal strength and readability is understood to mean that reception is loud and clear. If reception is other than loud and clear, it must be described with the appropriate prowords.