Parts required are a couple of Rubber Ducky Antennas, suitable connectors, a single OA5 diode and a metal enclosure.
The schematics are as shown below.
For in-band operation the 600 kHz fundamental crystal oscillator output is mixed with the incoming signal.
For cross-band operation the 290 MHz 5th harmonic of the 58 MHz overtone oscillator is used.
In-band & cross-band repeater operation is easily demonstrated using the handheld rigs.
Down-link signals are quite strong inside the shack.
However the range of the demo repeater is yet to be checked.