01-06-2012, 09:25 PM
Thanks for reading my post and for your erudite comments Lawrence!
The other thing that's making me feel that the middle winding in each of the two coils is the coupling coil (The aerial one certainly is), is that the circuit shows two of the windings in each coil tuned by a slug, and one not. Given that there is a slug at each end on the coils, that figures, unless of course the cores were screwed well into the coil where the centre winding is site.
I do have an inductance meter so can measure the inductance of the windings, then work out the tuning range when I've measured the capacitance of the tuning cap fully open and fully enmeshed. Fortunately, there are resonant frequency calculators on t'internet to do the sums! From long ago, I recall a rhyme to help remember the formula: 'one over two pi root LC, gives you the resonant frequency'. (Or words to that effect!).
As to the eventual alignment, (says he, more in hope than expectation!), data sheets for similar TRF sets such as Champion ones may provide some useful info.
The other thing that's making me feel that the middle winding in each of the two coils is the coupling coil (The aerial one certainly is), is that the circuit shows two of the windings in each coil tuned by a slug, and one not. Given that there is a slug at each end on the coils, that figures, unless of course the cores were screwed well into the coil where the centre winding is site.
I do have an inductance meter so can measure the inductance of the windings, then work out the tuning range when I've measured the capacitance of the tuning cap fully open and fully enmeshed. Fortunately, there are resonant frequency calculators on t'internet to do the sums! From long ago, I recall a rhyme to help remember the formula: 'one over two pi root LC, gives you the resonant frequency'. (Or words to that effect!).
As to the eventual alignment, (says he, more in hope than expectation!), data sheets for similar TRF sets such as Champion ones may provide some useful info.
Regards, David.
BVWS Member.
G-QRP Club Member 1339.
'I'm in my own little world, but I'm happy, and they know me here'
BVWS Member.
G-QRP Club Member 1339.
'I'm in my own little world, but I'm happy, and they know me here'
