[ARC5] BC-453/Q5er Converter

[Ian Wilson]

The general receiver schematic shows the antenna being connected to the top
of the input coil (L1) through a capacitor (C1). The grid of the RF
amplifier tube
is then tapped down on the coil.

For the 190-550kc receivers, L1 is 285 turns with the tap at 198 turns; C1
is
11pF. At 370kc (mid-frequency), the reactance presented by 11pF is 39k ohm.

At resonance, the impedance of the input tank circuit will be large and
resistive,
so the input will look like 11pF in series with a large resistance.

This will match reasonably well to an electrically short antenna. Matching
to
50 ohms wouldn't be easy (but there is probably no need anyway).

73, ian K3IMW