[Boatanchors] Cheap & Easy Selectivity

[mac]

Yes, common way to couple a BFO signal into a 2nd detector in many  
vintage receivers.  The BC-348, for ex. uses a wrap of this kind.   
Still two wires twisted together albeit in a novel way.

Dennis D.  W7QHO
Glendale, CA

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On Aug 22, 2009, at 2:24 PM, Alex Whitaker wrote:

> "...it is possible to capacitively couple the antenna directly to the
> next RF amplifier grid, or to the mixer input grid, by wrapping an
> insulated wire around any exposed wiring in the grid circuit.  This
> forms a gimmick, which has a few picofarads of capacitance to the wire
> around which it is connected."  Electronic Communication - 3rd  
> Edition -
> Robert L. Schrader.