500kHz - here's the plan

Brainstorming together helps sometimes. Here comes the plan:

1. build a MEPT for 3500800Hz using a crystal (e.g. from Nick)
2. build a down-converter using a 3.000MHz standard crystal

Not only allows this concept for dual band operation, it has added value, as one could also down-convert (transvert) signals from a regular transceiver, e.g. FT-817, allowing for WSPR & Co.
When using this in transverter mode, I would go for a 3.000MHz canned oscillator, since no pull is required.