@lis610 I have found with a 499K resistor the range is reduced to about 1.2m in a ABS box. With a 1Mohm it was about 3m, I do not have many high value SMD resistors to experiment with but the lower the value the lower the range. [image: 1533564348058-img_4277x-resized.jpg] Just tried with a 333K and it operates about 0.8m in free air.