Actually, scratch that, the Valon modules only go down to 10 MHz. 1 MHz-
3 GHz is a tougher requirement because none of the off-the-shelf PLL/VCO chips go that low.On third thought, if you bought one of the 5009 modules, you could just leave one of the channels set to 6 GHz and drive a ZX05-153LH-S+ or similar mixer with it, with the other channel tuned to 3000-5999. Depends on how clean the output needs to be. There will be plenty of spurs, but if you want to spend more time and less money you can dodge them in software.
-- john, KE5FX