it seems I managed to build a pretty good ferrite coil (abot 80 turns of Litz wire over a bundle of seven 20cmx1cm rods). Nulling and peaking seem acceptable for my purposes. With current var cap, tuning range is about 160-650 kHz and could easily be moved to lower frequencies by adding a parallel fixed capacitor. Until now I have only made some quick tests by inductively coupling the coil with the internal ferrite of a portable radio. I would like now to make the antenna suitable also for direct connection with a 50 ohm input. What do you suggest: to add for example a transformer or a buffer amplifier (or both :-))? If a transformer is recommended, is it advisable to use the main coil as the primary winding?

 

73

Daniele IZ5WWB