19-01-2015, 06:32 PM
Thanks Lawrence. That certainly looks similar. Now all I need is the Aerial version. Perhaps I could make one, that is the one I have without the Reaction Winding.
Yes, it was remiss of me not to measure the actual working Inductances.
So, measuring from 'Grid' to 'Earth' gives 1.53mH for both Coils and 160 MicroHenries for the MW Winding, ie with the LW Winding shorted out.
I also dug out a Baseboard Tuning Capacitor which measures 530pF fully meshed.
Assuming that the actual Range of the Capacitor is 30pF - 530pF I make that:-
LW - 743kHz to 177kHz or 404m to 1690m.
MW - 2297kHz to 547kHz or 130m to 548m
Of course that ignores Strays which will change things a bit, more so on MW I would think.
I'll have to look out a suitable piece of Ply, join them together and see where they tune. With an OA91 and a pair of 'phones I might even hear something.
Alan
Yes, it was remiss of me not to measure the actual working Inductances.
So, measuring from 'Grid' to 'Earth' gives 1.53mH for both Coils and 160 MicroHenries for the MW Winding, ie with the LW Winding shorted out.
I also dug out a Baseboard Tuning Capacitor which measures 530pF fully meshed.
Assuming that the actual Range of the Capacitor is 30pF - 530pF I make that:-
LW - 743kHz to 177kHz or 404m to 1690m.
MW - 2297kHz to 547kHz or 130m to 548m
Of course that ignores Strays which will change things a bit, more so on MW I would think.
I'll have to look out a suitable piece of Ply, join them together and see where they tune. With an OA91 and a pair of 'phones I might even hear something.
Alan
