Here's what I have so far. Hopefully this will be legible as an inline image. I'm a Kicad noob, so be gentle :)

I used Jim's original design with the roll-your-own mixers. This is the receiver only. There is no VFO, transmit mute or audio amp. My issue with the discrete audio amp as designed by Jim is that hard to find audio transformer. I'm not sure if I should add audio amplification to this board or just do the audio functions on a different board. Thoughts?

I plan to use an Si5351 ebay board and an arduino uno as a VFO/LO to get it running (commonly available code), then possibly design?a simple, low power vfo/display.

My intention is to use mostly surface mount parts (0805 size resistors and caps, SOT-23 size transistors and diodes).

Opinions are welcome!

Best regards,

Mike M. KU4QO

On Sun, Dec 15, 2019 at 9:46 AM Mike Maiorana <zfreak@...> wrote:

Thanks Jerry.?

I spent some time this morning looking at the different versions of this rig, from the original to the Norcal version. The first thing that struck me was how crowded and complex the Norcal board looks when built. I'm sure they spent a tremendous amount of time with the redesign and layout of that board. Not for the faint of heart.?

They made some substitutions, like replacing the discrete?mixers with ADE-1 mixers. I am curious as to why Norcal kept the audio amp the way they did instead of going to a simpler integrated amp. Any ideas? They also did away with the variable bandwidth IF filter.?

I thought?it might be fun to lay out the receiver section using mostly surface mount parts. Not necessarily to get it smaller, but instead to make it less congested.?

I bought a couple of the Si5351 boards from Ebay. I could use those as the VFO, with plans to go to a more elegant (lower power) solution later.

This sounds fun, but maybe it's just because I had too much coffee this morning. I'll start adding things to Kicad and see where I end up.?

Best regards and 73

Mike Maiorana

KU4QO

On Sat, Dec 14, 2019 at 7:20 PM Jerry Gaffke via Groups.Io <jgaffke=[email protected]> wrote:

The Raduino used on the uBitx consists entirely of a 5v regulator, an Arduino Nano clone, an Si5351, and a standard 16x2 LCD with backlight.
Power consumption is 40ma without the display, the display (mostly the backlight) sucks another 20ma.
? ??/g/BITX20/message/52886
The linear regulator is typically powered from the main 12v supply, so that Raduino heats the room with 60ma*12v = 0.72 Watts.