This is based on HF5L Club work, as it’s hard to find (and expensive) a 23cm SWR/Power meter,

« A dual meter would be much more convenient for measuring the standing wave ratio (SWR) and return loss. Reinhardt DC5ZM also developed dual meter using two modules with AD8318. »

this use two -40db coupler from China, sketch has been recoded to match atmega328P, with two digital buttons, and I2C display 2×16, the goal is to measure some watt’s, not miliwatt with this unit.