Tapping on ferrite rod antenna


Phillips
 

I have noticed that some receivers have a tap in the windings of the ferrite coil.  It is about 20% along the length of the coil.  I would like to know the purpose of the tap.  Currently I am working with a Tecsun DR-920.  It is a chip-based receiver and so chasing the circuitry achieves nothing unless you know the internal workings of the chip.  I also have the MW loopstick from a low performance radio that was pulled to pieces when it failed and it too has a tap on the loopstick winding.

Is this tap for impedance matching purposes or could it be the "tickler" portion of a q multiplier?

Any ideas or contributions most welcome.

All the best,

Ray


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