Turns out my troubles with using the 868 MHz OOK radio next to the RFM12B module were caused by a silly software mistake (I mixed up the port assignments). No hardware or RF issues after all.
Latest sample output:
(the VOLT and BARO readings are bogus because the hardware is not connected)
As you can see, it’s receiving both packet types now. Still some trickiness with allocating the port signals properly, since some lines do require specific pins: the OOK receiver uses the analog comparator, but the ADC gets used as well, so I’ll need to adjust things a bit to use a pin change interrupt instead (used a crude workaround for now).
So now the basics are there to receive all types of signals with a single JeeHub: packets from other JeeNodes using the RFM12B, an 868 MHz OOK receiver for weather data and the FS20 remotes, and a 433 MHz OOK receiver for picking up KAKU remote commands (and possibly some other cheap weather sensors later).