[AMPS] splatter

[Rich Measures]

>Tom,
>
>I think that the confusion on 'maximum plate current at zero grid volts'
>occurs because the statement should say ' maximum plate current in the
>RF cycle flows at at zero grid volts.' 

How could there be any confusion?  
- The grid operates exclusively in the negative region in Class AB1.   
- Maximum peak anode current occurs when the grid moves in a positive 
direction and reaches 0v. 
.  This is explained in *Amplifiers*.  

>The RCA Tube Manual TT5 (1962)
>uses the term as Rich put it, and that's what I read it as, but looking
>at it again, I can see that it easy to cause confusion. In AB1, where
>there isn't any grid current drawn, obviously the grid doesn't go
>positive, so the maximum voltage on it is zero. Minimum voltage (which
>is actually the maximum negative voltage excursion) is thus twice the
>bias.
>
... ...and during that interval the anode current is cut off. The action 
takes place between roughly neg.200v on the grid and 0v on the grid.   
>
>Rich asked where the curves of IMD against grid volts were in The Care
>and Feeding of Power Grid Tubes. 

This Rich did not ask where such curves were.  The statement that I did 
not buy is that drawing grid current (Class AB2) decreases IMD.  I use a 
Class AB1 amplifier, and I know that such a statement is unsliced 
bologna. ..... AB2=doo-doo.  
...snip...
>2. Has anyone heard of any successful use of Doherty or Terman-Doherty
>linear amplifiers on HF SSB?

No.  The way I understand it, changing frequency with one is a major 
undertaking, Peter. 

- IMO, increasing efficiency from 60% with tubes, and 45% with 
transistors, to 90% would make minimal difference.  We are talking about 
a third to a half S-unit.  Normal QSB is much more than that.  
Rich---


R. L. Measures, 805-386-3734, AG6K   


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