The ALPS VCO 1679C is operational. Power supply and tuning voltage have been connected now. Also a small MMIC, the MSA-0866 from Hewlett Packard has been connected to the output to increase the output level from about 0 dBm to abt. 12 dBm.
I viewed the spectrum on the SDR receiver and found I could generate a stable signal in the 23 cm band. Here you see a clean signal around 1.256 GHz:
The VCO can be tuned between 1100 and 1350 MHz. I think the long and short term stability are good enough to use the free running VCO for 23 cm ATV transmission. No PLL required !