Transmitter attack-time delay

In telecommunication, transmitter attack-time delay is the interval from the instant a transmitter is keyed-on to the instant the transmitted radio frequency (rf) signal amplitude has increased to a specified level, usually 90% of its key-on steady-state value.

Note: The transmitter attack-time delay excludes the time required for automatic antenna tuning. Source: from Federal Standard 1037C and from MIL-STD-188