Here is my 472kHz 630m transverter. A design by Roger G3XBM. The schematic I built is here.
I added TX/RX switching, a switchable 12dB attenuator for 0.5w or 8w drive and an output via a 100pF capacitor for attaching a frequency counter.
The local oscillator uses a 3.2768MHz crystal, and is set to 3.2765MHz by a 5-65pF trimmer. The input frequency minus the local oscillator frequency determines the output frequency. An input of 3748.5kHz gives an output on 472kHz.
Output power is about 12w at 13.8v.
And the first QSO, George M1GEO on CW!
And the first few WSPR reports on an unmatched antenna! ERP must be microwatts..