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Here's my solution for a 2m rig having only an integrated rubber ducky antenna and no connector for an external antenna.
A vintage unmarked inductor/transformer had been lying neglected in my junkbox for decades and I had to resurrect it.
Resistance checks showed that 2 windings, with a tap each, are terminated in its 6 pins. One measured 70 Ω with a 5 Ω tap and the other less than 1 Ω. A threaded core, with a...
A fully tarnished, shiny black silver artefact was tried out as a detector in place of the germanium transistor in my series-tuned, shunt-fed crystal radio.
Fortunately the presence of an untarnished spot facilitated the metal to metal connection.
A length of pencil 'lead' was used to probe...
This series-tuned, shunt-fed crystal radio was built using parts salvaged from a vintage / battered SCR - 578 lifeboat radio (popularly referred to as 'Gibson Girl').
'Gibson Girl' Crystal Radio - Schematic
It consists of a baseplate, antenna tuning coil, antenna tuning capacitor and a...
A diode with a forward voltage drop as low as 0.25 V may be configured by interconnecting the base and emitter of a Germanium transistor.
Basic Shunt-fed Crystal Radio
It's an ideal detector for a shunt-fed crystal radio.
Low capacitance diodes are a must for UHF crystal radios.
It follows that they are to be so wired that the capacitance between their leads is kept to a minimum.
This does not imply that the leads are to be cut to minimum length. In fact longer leads facilitate antenna-diode...
A loop antenna crystal radio is of interest, on account of its portability, though it is no match for a crystal radio using an external vertical wire antenna and earth.
If it's performance could be considerably improved with increased loop size, then its portability would be the first casualty...
1. The well-known parallel-tuned, series-fed circuit.
Parallel-tuned, series-fed Crystal Radio circuit.
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