Is there a publicly published circuit diagram for the push button and tuning knobs, connect to p1 of radioduno, that marked as a0 to a?, analogue input.
Some switch use adc, switch resistor, so each push button produce different voltage. Hence, one line for many switch. As in dfrobot arduino lcd and switch plug in,widely used.
Chip input line can pick up rf and rectify it as analogue voltage. Put 0.1uF on the adc line normally work, if it use the adc design as above. Tie the switch wiring away from rf final pa area. In extreme case, use screen cable and copper fold wrapping, as in one of my work case.? Since the kit use normal cable, likely tie it away ftom rf pa is enough
73 Simon
On Monday, December 3, 2018, iz oos <
and2oosiz2@...> wrote:
Ground loop somewhere? Is it connected with other stuff except the antenna?
