KL7UW


1296 300W AMPLIFIER

  

  March 11, 2015 Update

 With 30w driver amp installed, I have tested up to 130w output.  Saturation seems to be appearing so max output 
 is probably 130-140w.  For the meantime I am limiting operation to 120w until I have my Bird 250E element calibrated.

 I am QRV for CW and JT65c contacts.  

  Drive  Output  Ipa    Vc        RF Det
  10w   120w     ---     27.65v    1.6v
  
  Nov. 3, 2014 Update

  The first 150w amplifier is completed and tested.  Prewiring of control board and amplifier
  Is being done on the pallet that will be installed in an all-weather enclosure to be attached
  to the rear side of the dish in the next two days. (photos soon)

  Tests:

  Drive  Output  Ipa    Vc        RF Det
  2w     35w       4.6a  27.7v    1.18v
  5w*    80w       9.0a  27.28v  1.67v
  5.4w   90w
  8.6w   120w   10.3a  27.17  1.96v  
           

  Tests with Bird43 power meter and 100E element into 50w coax load.
  *Note: 5.2 w is current drive level available at the dish.

  Test at the dish:  90w RF output with 27.5v at the PA with the 16-foot No. 8awg dc cable from the 28v PS.
  10 amp current shunts were installed but not wired or tested.  No reflected RF detected when terminated into the feed horn.


  Description of 300W Amplifier Kit from W6PQL that uses four XRF-286 LDMOS transistors.

Schematic Diagram of 150w board:






















Photos:
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W6PQL Control Board Block Diagrams:















Control Panel Block Diagram:













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