QBL 5/3500 VHF amplifier


Anode Compartment

tube socket details

cathode compartment


A view of the still unfinished PA. The eccentric teflon tuning devices are adjusted using a 1 : 80 ball drive. Please note that the size of the capacitor stators (mounted to the lecher) have been changed at a later stage.


Tube with teflon chimney and loading capacitor flapper. Note the the horizontal part of this flapper is of such width and height it represents a horizontal transmission line of 50 Ohm.

May04$03.JPG (219345 bytes)


Decoupling of high voltage input. The vertical brass plate represents the Hv decoupling capacitor

May04$05.JPG (216373 bytes)


The anode compartment of the PA with neutralisation probe :

Jul07$01.JPG (232148 bytes)


Details of the tuning capacitor. The moving part of the capacitor is made of a plate of beryllium-copper, providing good flexibility.

Oct28$04.JPG (235735 bytes)


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