KL7UW
HF 300W Power Amp



  I have a kit consisting of a pc board and parts marketed by Communications-Concepts, Inc.  
  It was accompanied by a document, EB-27A.  
  
  Photos:
   
 











    
  
  • Kit before assembly
    •    
  • Assembled Amplifier

  Testing with a bench power supply at 28v currrent limited to 3 amps, results in 18w output with less than 1w input.  
  Drive runs current draw up to 5amps with voltage dropping off to 15v.  Setting Bias to 0.680vdc with zero drive
  results in 180ma idle current (zero drive) on the MRF-422's).

  Testing using the 28v-20amp PS:  





RF TEST DATA


 BAND 
 DRIVE(W) 
 OUTPUT(W) 
 Ic(A) 
 Vc(V) 
 BIAS(V) 
 GAIN(DB)


 


 160M 
 14.0
 150
 12.0
 27.0
  X.XX
 10.3




  80M 
 15.0
 170
 14.0
 27.0
  X.XX
 10.5

 


  40M 
  7.0
 100
 10.0
 27.0
  X.XX
 11.5




  40M 
 15.0
 190
 16.0
 27.0
 0.715
 11.0

 


  20M 
  7.0
 130
 12.0
 27.0
 0.669
 12.7




  20M 
 15.0
 270
 17.0
 27.0
 0.698
 12.6

 


  15M 
 15.0
 270
 17.0
 27.0
  X.XX
 12.6

 


  10M 
   7.0
 180
 14.0
 27.0
  X.XX
 14.1




  10M 
 15.0
 240
 17.0
 27.0
  X.XX
 12.0

 

 



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