The OHR QRP20/40 uses a superhet receiver with crystal filters.

The receive signal is fed into NE602 mixer and another NE602 detector. Four 9 mhz crystals are used for the receiver IF filter.

The transmitter uses a MC1496 IC for a mixer into a single buffer stage and final amplifier.

The VFO runs at 5mhz and has enough range to cover the lower portion of the 40m or 20m band.

The power supply is 12 volts, with about 60ma on receive and 800ma on transmit.