Rev 3: November 2006 New pictures & measurements results After testing and checking of original circuit, idea was to modify arrangement of capacitors in the amplifier output PI network. As power output (with same input) was measured ridiculously less in low bands than in higher bands (sometimes, impossible to match in low bands), some additional mods have to be done. This in order to have better results on all ham bands. Spectral purity after modification measured in all bands is excellent. Measurements and curves of the modified amplifier The modifications are quite simple.You will have to modify the contacts arrangement in the 5 positions rotary band switch, and modify fixed capacitors arrangement. ************************************** EXCEL spreadsheets APPROXIMATIVE calculations. Results are not perfectly accurate, due to the variable parasitic parallel capacitance of the variometre L2, impossible to take into account here .. Nevertheless, it works.... WORKS HERE WERE REALIZED ON NEW MODEL 6M1 The 5 bands rotary switch ( "Trommel" ) and modifications in band 2
Fixed capacitors arrangement The new 20 pF 10 kV capacitor & new placement of the 12 pF Download modification documents: PI GU43b MODIFICATIONS.zip |