On Sat, Sep 15, 2018 at 08:54 AM, Tom, wb6b wrote:
At that final stage in the BITX40 it can put out 7 watts. Would there be any advantage in reworking the uBITX so that the stage with?Q92-Q93-Q96-Q97 was replaced with a IRF510 and the transformers and bias rewired to be like the BITX40 final? Then let that reworked stage drive the Push-Pull IRF510 PA stage of the uBITX.
FYI all of the images I have of the schematics for ubitx and Bitx40 are sufficient resolution that its my eyes not the printed image.
No.? IT like installing a 400CI engine for the wiper motor.
For the q90 a better device with higher FT.
For the predriver and driver a better device might be BS170 and maybe others.
I'm keeping track its not the 10th time repeated here....
you need about .5W from the driver the IRF510s (to 10W).
you need about .07W to drive the driver
and you need a milliwatt or three to drive that stage.
Not much of that requires big devices with heatsinks.
Allison
