Apparatus for providing oscillator frequency stability

An apparatus for providing oscillator frequency stability is disclosed. The apparatus includes an internally ovenized oscillator module having an oscillator and an inner heater to maintain the oscillator at a first temperature during operation. The apparatus also includes a thermally conductive cover for forming a first compartment to contain the internally ovenized oscillator module along with multiple heaters. The heaters are in thermal communication with the thermally conductive cover and the substrate to form an oven to keep the internally ovenized oscillator module at a stable second temperature during operation. In addition, the apparatus includes a thermally insulative cover for forming a second compartment to contain the first compartment.