[hpsdr] 400w Class E linear amplifier

[Bob McGwier]

Bob McGwier wrote:
> He achieved 90% efficiency on at least one tested band for the Class E 
> phase channel amplifier.  He shows IMD plots for 15 and 80 meters.   
> And he does do a class S pulse width modulator.  But I want to warn 
> that, in my opinion,  he has committed a design mistake.
>
> The efficiency will be higher and the IMD lower if and only the driver 
> is ALSO modulated by the switching power supply (PWM, whatever).   The 
> gain of Class E amplifiers is low enough that you have to have a 
> fairly hefty driver.  If the driver is run in class AB as he 
> recommends in the final page of the article (presumably to reduce 
> IMD),  power added efficiency of the amplifier will suffer.
>
> It remains to be seen if we can do a two stage EER or HELAPS multi 
> band amplifier.   Single band has been accomplished by AMSAT through 
> the good work of Marc Franco, N2UO and his friends on 145 MHz.  Marc 
> and I directed a student's independent study and he designed a very 
> efficient 2400 MHz amplifier which received a special award at an 
> amplifier efficiency competition.
>
> I have Karl's thesis and papers and other works in English by Karl, 
> Jan King,  and Gordon Hardeman.   You might recognize Gordon 
> Hardeman.  He is the chief design engineer for and Molly (W0MOM) his 
> wife, run Alpha amplifier.   I am happy to see that Josef references 
> Karl's thesis.  I do feel that the paper he did in the 1990's with Jan 
> and Gordon is much more complete.
>
> *http://www.hamsdr.com/personaldirectory.aspx?id=733  (this is a pdf 
> file.  We really need to fix the removal of the subscript).  (in 
> English).
>
> Karl's thesis: http://www.hamsdr.com/personaldirectory.aspx?id=734  
> (auf Deutsch)
>
> Karl's VHF Communications article (in English)

Oooops  http://www.hamsdr.com/personaldirectory.aspx?id=735
> *
> Bob
>
>


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