You beat me to it, Geert! The only difference is that I use an FT817 so I built a simple parallel tuner, a coil and a capacitor. As it stands it tunes 80, 60 and 40, and just about does the job on 20 metres - with no switch. I am about to modify it with a bigger coil and switched taps so that I can cover 160 metres and perhaps a couple of higher bands. Most of the UK summits do not have trees so I set the main wire up as an inverted V with a 7 metres roach pole.
The W3EDP antenna is an ancient design dating back to 1936. It was regarded as a DX magnet then and it still works well today!
Brian