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Class AB (and class A) keeps the pills turned on during little or no RF input/drive.
The AM carrier applies RF drive at all times while transmitting, so the pills stay ON.
However, during the negative cycle of modulation the power can drop to zero for that short period. A class C amplifier can generate a small amount of distortion on the peak of negative modulation. But usually the vast majority of distortion of this kind is from the CB transmitter.

I think 74IN said it best. CB is not about being clean. class C is fine for AM CB.
Another way to think of it: NASCAR is not about reducing global warming.

The "ultimate solution" for an AM power transmitter is collector modulation, or plate modulation as they called it in tube days. In common radios like the Cobra-29, the collector voltage on the finals are modulated by a audio power amplifier. The "ultimate solution" would be to scale up the audio power amplifier to power the (big) amp, and just feed the RF input with a dead carrier.

<blockquote data-quote="dudmuck" data-source="post: 118974" data-attributes="member: 3904">Class AB (and class A) keeps the pills turned on during little or no RF input/drive.The AM carrier applies RF drive at all times while transmitting, so the pills stay ON.However, during the negative cycle of modulation the power can drop to zero for that short period.&nbsp; A class C amplifier can generate a small amount of distortion on the peak of negative modulation.&nbsp; But usually the vast majority of distortion of this kind is from the CB transmitter.I think 74IN said it best. CB is not about being clean.&nbsp; class C is fine for AM CB.Another way to think of it: NASCAR is not about reducing global warming.The &quot;ultimate solution&quot; for an AM power transmitter is collector modulation, or plate modulation as they called it in tube days.&nbsp; In common radios like the Cobra-29, the collector voltage on the finals are modulated by a audio power amplifier.&nbsp; The &quot;ultimate solution&quot; would be to scale up the audio power amplifier to power the (big) amp, and just feed the RF input with a dead carrier.</blockquote>

[QUOTE="dudmuck, post: 118974, member: 3904"] Class AB (and class A) keeps the pills turned on during little or no RF input/drive. The AM carrier applies RF drive at all times while transmitting, so the pills stay ON. However, during the negative cycle of modulation the power can drop to zero for that short period. A class C amplifier can generate a small amount of distortion on the peak of negative modulation. But usually the vast majority of distortion of this kind is from the CB transmitter. I think 74IN said it best. CB is not about being clean. class C is fine for AM CB. Another way to think of it: NASCAR is not about reducing global warming. The "ultimate solution" for an AM power transmitter is collector modulation, or plate modulation as they called it in tube days. In common radios like the Cobra-29, the collector voltage on the finals are modulated by a audio power amplifier. The "ultimate solution" would be to scale up the audio power amplifier to power the (big) amp, and just feed the RF input with a dead carrier. [/QUOTE]

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