With the circuit we present it is possible to receive signals from the shortwave band in the average waveband of a common AM receiver. The frequency range will depend on the crystal used. For example, the original circuit found in 1970 documentation was designed to receive signals from the 20-meter band (15 MHz), using a 14.2 MHz crystal for this purpose. Signals from other bands can be received with other crystals and also by switching the tuning circuit. The circuit does not include the power supply, which even if it is a valve circuit is only 12 V, because the valve used is of a special type of low voltage. In this way, the source is not a problem for this circuit, but only the valve itself.
