The following lines were added (+) and removed (-):
3-500 - Heathkit SB-220 and SB-221 HF linear amplifier uses 2. Other brands also use, Ameritron, Henry, etc.. 3-500Z - Triode. Heathkit SB-220 and [[Heathkit SB-221 HF Amplifier]] uses 2. Other brands also use, Ameritron, Henry, etc.. 572B - RF tube seen in ham radio. [[Dentron 160-10 HF Amplifier]] uses 4 572B Tubes. 4-400 - Tetrode RF tube for amplifiers, oscillators or modulators. AM broadcast transmitter. <small><small>keywords: amplifier tubes cb citizen band c.b. </small></small>