I used full shields from some scrap HT1250 radios on my first (Gecko) NanoVNA but never really had time to test it. There are photos from the end of June of my work, in the photos area of the forum.?
I like your idea of grounding all unused pins, after tri-stating or setting them to gnd through the firmware.?
On Thu, 31 Oct 2019 at 8:50 PM, Raymond Domp Frank<hewpatek@...> wrote: On Fri, Nov? 1, 2019 at 12:02 AM, Larry Rothman wrote:
how much digital noise reduction do you think would occur by placing bypass
caps on all the unused uP pins to gnd (of course).
Not exactly sure if I understand what you mean. I'm not familiar with these processors but I'd prefer not to bypass them but just short them to ground if firmware could set them appropriately during startup (either low or input). I cannot quantify the improvement but just shorting them to ground is free so no reason not to do that.
I'm certain that PCB layout offers a lot of room for improvement. Full shielding (capping) may not be much better than just placing "walls".
Raymond
