W8QBG - Recent Projects


On to W8QBG Recent Projects II Page 

Back to W8QBG Main Page 




    


The stock Bauer 707, cleaned up a bit from its sojourn in the Palm Springs desert.  The transmitter runs a pair of 4-400's in the PA, modulated by a pair of 4-400's.

(Click here for larger photo ~200K)

(Click here for largest photo   ~1.5 Meg)




Click here for over-the-air audio from W8QBG on the Bauer 707 describing his ART-13 mods and other hardware subjects.  (Recorded 0730MST,  10-Sep-2006, in Glendale AZ,  ~1.5 Meg)



    


Bauer 707 after conversion to HF operation.  Added bandswitch (top center) and output loading control (top left) while retaining existing plate tuning (top right).  Exciter mods described below.  Silver disk between mod and PA tubes is an improved cooling-air interlock switch.

(Click here for larger photo ~160K)

(Click here for largest photo   ~1.5 Meg)




    
  


 Plate tank mods for HF added a band switch to select taps on existing tank coil and a large (2500 pF) variable loading capacitor.
Plate tuning uses the existing vacuum-variable cap.

(Click here for larger photo ~160K)

(Click here for largest photo   ~1.5 Meg)




    


Old BC-band PA tank, a Pi-L network, shown for comparison. 

(Click here for larger photo ~150K)

(Click here for largest photo   ~1.6 Meg)




    


Extensive exciter mods: added tuning adjustments to driver stage, switch for external driver, crystal socket on front panel and substituted 6146 for 6CA7 for  improved drive on 40 meters.

(Click here for larger photo ~160K)

(Click here for largest photo   ~1.6 Meg)




    


 Rear-panel view of exciter/driver mods.  External-drive connection is at left.  25 watts CW from an amateur-radio transceiver will produce legal-limit power out.

(Click here for larger photo ~150K)

(Click here for largest photo   ~1.5 Meg)




    


 Original exciter/driver stages showing 6CA7 tube.  Note lack of access to crystal sockets and tuning controls.

(Click here for larger photo ~150K)





    


 Rear view of stock Bauer 707.

(Click here for larger photo ~200K)

(Click here for largest photo   ~2 Meg)




    


 Industrial-strength fan installed in place of stock unit for additional cooling in Arizona summers. 

(Click here for larger photo ~200K)

(Click here for largest photo   ~2 Meg)




    


 Bauer 707 "heavy metal".  No mods made to power-supply components. Modulation reactor (center) is a Peter Dahl rebuild.

(Click here for larger photo ~200K)

(Click here for largest photo   ~2 Meg)




    


 AN/ART-13  

(Click here for larger photo ~200K)

(Click here for largest photo   ~2 Meg)




    


 ART-13 in Studio 'B' 

(Click here for larger photo ~200K)

(Click here for largest photo   ~2 Meg)




    


 ART-13 Power Supply 

(Click here for larger photo ~200K)

(Click here for largest photo   ~2 Meg)




    


 Homebrew Grounded-Grid Xmtr RF Deck (2 x QY5-500's)

(Click here for larger photo ~200K)

(Click here for largest photo   ~2 Meg)




    


 Homebrew G-G Xmtr Modulator Deck (2 x 810's) 

(Click here for larger photo ~200K)

(Click here for largest photo ~2 Meg)




    


 Homebrew 4-1000 rig currently at mechanical-layout stage of  design flow.

(Click here for larger photo ~200K)

(Click here for largest photo  ~2 Meg)




    


 Speech Amp. using "guts" of HP200 audio oscillator 

(Click here for larger photo ~200K)

(Click here for largest photo   ~2 Meg)




    


 Speech Amp., rear view

(Click here for larger photo ~200K)

(Click here for largest photo   ~2 Meg)










On to W8QBG Recent Projects II Page 

Back to W8QBG Main Page