smoke
n.— «I think Tree means to tune the gamma match with the variable capacitor for best transmitter output, or “maximum smoke,” as it is sometimes called.» —“The K7RA Solar Update” by Tad Cook ARRL Dec. 1, 2008. (source: Double-Tongued Dictionary)
Further reading
There was a time when William Shakespeare was just another little seven-year-old in school. Classes in his day were demanding — and all in Latin. A new book argues that this rigorous curriculum actually nurtured the creativity that later flourished...
Book recommendations and the art of apology. Martha and Grant share some good reads, including an opinionated romp through English grammar, a Spanish-language adventure novel, an account of 19th-century dictionary wars, and a gorgeously illustrated...
Every good transmitter operator knows that you’re supposed to “dip the smoke and peak the flame”! A dip in the current when tuning the final amplifier stage indicates that the circuit is in resonance, and thus at maximum efficiency. Then the output coupling is increased just to the point of maximum power output; if it’s set too high, it’ll detune the circuit and cause loss of power, or worse yet, unwanted signals such as harmonics or parasitics, which sap the signal strength even further.
Also may relate to the old hot-rod auto maxim: “Set for skim and tuned for minimum smoke!”