[hpsdr] 400w Class E linear amplifier

[Bob McGwier]

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)
*
Bob




Phil Harman wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
> I've  uploaded a copy of    Josef's, DJ7AW, article on a 400w Class E linear 
> amplifier to hamsdr.com at
>
> http://www.hamsdr.com/personaldirectory.aspx?id=732
>
> Should form the basis of a very nice PA for HPSDR.
>
> 73's Phil...VK6APH
>
>
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