Tiny, cheap, simple, accurate, self powered resistive SWR and power meter for SOTA and back packers
The SWR and power meter is based on a resistive bridge. The forward and reflected power is sampled by an ATTiny13A micro controller. The micro controller is powered by rectifying a tiny fraction of the input power, and the measured SWR and power is displayed by smoothly interpolating 6 high efficiency LED diodes.
Firmware for the ATTiny13A is found here, while the simulation and design data is found here.
The following picture shows the initial prototype of BlinkySWR, indicating SWR slightly above 1:1.
