[Fwd: Re: A radio can NEVER work without a ground?]
mo at ccr.org
Sun Jul 15 18:14:32 CDT 2007
> The input circuit, however, can also consist of a tuned circuit such as
> a length wire wound around a ferrite rod, and tuned with a capacitor.
> Magnetic lines of force passing through the ferrite rod and the coil
> will induce a RF difference of potential across the two ends of that coil.
also, a balanced antenna (eg, a dipole) fed with a balanced line
(eg, ladder line) could be connected to the ungrounded primary winding
of the input transformer of a receiver's first stage. the secondary
could then be single-ended (ie, grounded at the bottom end) and
resonated by the first tuning capacitor.
the curiosity in my mind is that overwhelming dominance of coaxial
feedlines given all the secondary effects they display. i assume
it's a natural consequence of WW2 and all the technology developed
for that. Twinax certainly exists, but it's not available in as
wide a variety of forms and the connectors are expensive.
but some of that is self-fulfilling. if twinax had been popular
coming out of WW2, we might well have 50 ohm twinax feedlines and
balanced inputs and outputs on rigs.
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