I will fill the thread all by myself :-) ...

I was wrong... Having a closer look on the schematics and pictures of the
internal parts of the antenna revealed that I was missunderstanding the
schematics... (I'm not an electronic guy...)

This schematics is concerning the loop amplifier circuit based at the bottom of
the loop :
http://www.drmrx.org/forum/attachmen...6&d=1130372787

Then we have the "battery box" here :
http://www.drmrx.org/forum/attachmen...1&d=1128874226
and also :
http://home.arcor.de/carsten.knuetter/DE31_inside.JPG
http://www.drmrx.org/forum/attachmen...9&d=1132431663

OK. I think I will open the box to check if there is really a capacitor and what
is its capacitance... Unless someone knows ???

Thanks

Charly