[BC] Re: Continental 314r-1

[DHultsman5 at aol.com]

In a message dated 1/22/2008 7:26:35 PM Central Standard Time,  
avcradio at roadrunner.com writes:

but I am  not sure if it is driving the PA to full power.



*******************
 
The 314=R1 is a PWM modulated 1 kW. rig.  The Switch modulator is  single 
3-500Z operated in Class D mode.  The PA stage is two parallel  3-500Z's operated 
Class C.
 
The PWM Card controls the DC to the PA stage.  In order to have  carrier you 
will have to have drive and DC which comes thru the PWM  card.   Modulation 
will change the + and - voltages to the control of  the PWM card at an audio 
rate,  More DC to modulate the carrier positively  and less DC to modulate in the 
negative direction.
 
Now I believe you mentioned that you changed frequency.  If thats the  case 
you can have a whole new ball game since the output network is a  passband 
network not the typical second harmonic filter.  It filters out  the harmonics 
from the 70 kHz. and other frequencies other than the  fundamental which it is 
designed to pass with sidebands.  If the network is  not set up correctly the 
plate load will be off considerably.
 
My suggestion if you changed frequencies, and it is in Texas, is to have  
Continental Field Service come out and go thru it.   Ken  Branton in Dallas may 
want to work on it.
 
Dave 



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