Re: ubitx - stop press

Ashhar Farhan
 

The 2N2219 didn't have enough juice at higher HF frequencies (at least the ones in my junk box). The 2N3904s don't need a heatsink either. 

- f

On Mon, Dec 11, 2017 at 11:48 AM, AndyH <ahecker@...> wrote:
Just the close the circle, so to speak.  Farhan has additional comments in the sales write-up for the µBITX:
The power chain uses four common plastic 2N3904s in push-pull as drivers. The 2N3904s have enough gain at 30 MHz. The 2N2219s tried  earlier were found to have low gain at higher frequencies.
Andy, KG5RKP

On Mon, Nov 20, 2017 at 01:44 pm, AndyH wrote:
Thanks for the updated schematic!  What did you find that led to the change in the 45 MHz band pass filter (should the original LC network not be used?)?  Also - is it safe to assume that the pair 2N2219As were changed to 4 2N3904s in the driver to simplify or standardize the parts list?

On Fri, Oct 6, 2017 at 01:10 pm, Ashhar Farhan wrote:
I am plodding through the write-up part of the new version. in the meantime, here is just the schematic. not very different.
 
 
 
- f
 


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