[Milsurplus] TBW on the air

[Ray Fantini]

Just curious, did not get the picture being that I no longer subscribe to the regular part of the reflector and just use the condensed list and that don't include any attachments.
How did you do the power supply? Did you use the original 800 cycle source or did you build something for 60 cycles? The reason I as is that I found that using a 60-cycle power supply and the original keying circuit had issues with the discharge rate of the increased size of the filter capacitors.
The original 800 cycle supply used small filters so between key up and key down the discharge rate was so short did not have any issue but when going to 60 cycles had to increase the size of the filters and between keying the capacitors had enough charge to cause a strange keying chirp from the LO and IPA stage. I had to provide external bias to cut off the IPA when the key was let up.
Also, how are you addressing the power levels? The original power supply had different taps for different power levels and the tune position that removed plate voltage from the 803 but still provided screen, something that you think would destroy most power tubes but the 803 did not care. Think the 803 may be the toughest power tube ever built. Back in the day when I ran a TBW asked around and no one I have found has ever seen one fail.


Ray F/KA3EKH

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