A solid QSO this evening with G6ALB (2 miles away) on 6m AM using the 50mW SixBox rig with vertical antennas at each end. In the other direction, using the super-regen RX at my end, we did some sensitivity tests with Andrew putting a signal generator on and gradually dropping his AM modulated carrier. I was able to copy his signal when it was reduced to 0.5mW.
I also tried to receive a 7dBm carrier from Andy on 70.26MHz AM using the retuned super-regen RX, but was unable to hear it, although we were both using 6m antennas which were not resonant on 4m.
Currently I am putting a rebuilt SixBox in a real box. Later, I will make a breadboarded DSB version.
More details on the SixBox page of my website.