Mike took early retirement to look after his sick partner. He sadly died later following a stroke.
PF1 units were low power and some were converted to 70cm.
Simple QRP projects, 10m, 8m, 6m, 4m, FT8, 160m, WSPR, LF/MF, sub-9kHz, nanowaves and other random stuff, some not related to amateur radio.
When I started work a test was to convert the PF1 units to 12.5kHz channel spacing. The PF1's were widely used by the UK police.These were relatively QRP and the RX and TX were separate units. I think the police had to have base stations quite often. Still, it revolutionised policing in towns and cities.
See https://sites.google.com/site/g3xbmqrp3/vuhf/pf1
My 10mW ERP from the earth-electrode "antenna" in the ground was turned on at about 1810z. So far, spotted by one station. UPDAT...