One thing that I have done is to mount a Thunderbolt GPSDO, SR104 resistor, a 10V reference circuit, and the power supply in an insulated cardboard box box. I use Lady Heather's temperature control mechanism to set the Tbolt's temperature at one of the SR104's two points where it's resistance is 10000.000 ohms. Using just a fan, Lady Heather stabilizes the temperature swings in the box to around +/- 0.01C despite air conditioning swings, etc in the room. Long term RMS averages (say over 24 hours) are in the microdegree area.
One thing that I have done is to mount a Thunderbolt GPSDO, SR104 resistor, a 10V reference circuit, and the power supply in an insulated cardboard box box. I use Lady Heather's temperature control mechanism to set the Tbolt's temperature at one of the SR104's two points where it's resistance is 10000.000 ohms. Using just a fan, Lady Heather stabilizes the temperature swings in the box to around +/- 0.01C despite air conditioning swings, etc in the room. Long term RMS averages (say over 24 hours) are in the microdegree area.
