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Its true, both AM and SSB varies amplitude, but AM has a carrier thats always there when transmitting, and this carrier will keep class C pills turned ON except in the case of 100% negative modulation where for that instant of negative peak there is no RF (or very little).

I'm sure you all know that SSB has no carrier, so there is nothing to keep class C pills on, which is why the biasing is needed.

Another item to be concerned with bipolar biasing, is that when temperature increases, the transistor will increase gain and burn itself up in a run-away condition, unless bias is reduced at high temperatures.
Bipolar transistor biasing - Wikipedia, the free encyclopedia
see "Note on temperature dependence".
Its something to be aware of with a 2sc2879 with biasing for SSB.

MOSFETs have an advantage here of having the opposite behavior of reduced gain at high temperatures, preventing the runaway condition.

<blockquote data-quote="dudmuck" data-source="post: 125619" data-attributes="member: 3904">this thread is still going?Its true, both AM and SSB varies amplitude, but AM has a carrier thats always there when transmitting, and this carrier will keep class C pills turned ON except in the case of 100% negative modulation where for that instant of negative peak there is no RF (or very little).I&#039;m sure you all know that SSB has no carrier, so there is nothing to keep class C pills on, which is why the biasing is needed.Another item to be concerned with bipolar biasing, is that when temperature increases, the transistor will increase gain and burn itself up in a run-away condition, unless bias is reduced at high temperatures.<a href="http://en.wikipedia.org/wiki/Bipolar_transistor_biasing" target="_blank">Bipolar transistor biasing - Wikipedia, the free encyclopedia</a>see &quot;Note on temperature dependence&quot;.Its something to be aware of with a 2sc2879 with biasing for SSB.MOSFETs have an advantage here of having the opposite behavior of reduced gain at high temperatures, preventing the runaway condition.</blockquote>

[QUOTE="dudmuck, post: 125619, member: 3904"] [b]this thread is still going?[/b] Its true, both AM and SSB varies amplitude, but AM has a carrier thats always there when transmitting, and this carrier will keep class C pills turned ON except in the case of 100% negative modulation where for that instant of negative peak there is no RF (or very little). I'm sure you all know that SSB has no carrier, so there is nothing to keep class C pills on, which is why the biasing is needed. Another item to be concerned with bipolar biasing, is that when temperature increases, the transistor will increase gain and burn itself up in a run-away condition, unless bias is reduced at high temperatures. [url=http://en.wikipedia.org/wiki/Bipolar_transistor_biasing]Bipolar transistor biasing - Wikipedia, the free encyclopedia[/url] see "Note on temperature dependence". Its something to be aware of with a 2sc2879 with biasing for SSB. MOSFETs have an advantage here of having the opposite behavior of reduced gain at high temperatures, preventing the runaway condition. [/QUOTE]

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