i have been trying to hack out the tx pop. it is a far more intricate problem than it does seem at first. to cut a very long and painful story short, i am not yet there. but i have a partial solution.
add a 470uf (or a 220uf) capacitor in parallel to C50. The C50 is the 1uf capacitor that feeds the detector signal to the audio pre-amp. Increasing this to 470uf, prolongs the 'switch on' time of the audio preamp just enough to not hear the TX-to-RX thump.
can someone else too try this out?
i call it a partial solution because it doesn't suppress the rx-to-tx pop (which is not as bad as the tx-to-rx pop).