Re: RF power chain mods and improvements..

K9HZ <bill@...>

I have made roughly the same mods after simulating them in LTSpice and can confirm almost identical results/ power levels. 


Dr. William J. Schmidt - K9HZ

On Jun 11, 2018, at 5:32 AM, Nick VK4PLN <nickpullen@...> wrote:

Good Morning Allison, et al.

Just thought I'd throw a few cents in the hat.

I have managed to get my uBitx to output 16w at 80m to 14w at 10m. (CW key down)
In a nutshell, Q90 changed to MMBTH10 (20 for a few $ on ebay...) 220/300  pf cap across emitter resistors of all 3904 drivers, 2:4 wind BN43-202, 330pf mica on input. and RD16 with std feed back in place. Drive RV1 at 3/4. (maybe 20w at full?)

I have yet to check IMD and such but output seems stable.

I need to do more learning/testing...

My second ubitx will get the same mods except all the driver 3904 will be changed to MPSH10... and a common power feed(L8/L9) to the RD16 via a FT50-43 Bifilar. I have worked out a neat way to implement this on the STD board... Pics to come...

73 Nick VK4PLN 

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