Note that for an OCXO, the turning level temperature of the crystal needs to be greater as opposed to higher limit of the temperature range. It is because you might not Regulate a house's temperature at +25°C by using a furnace if the skin temperature is +35°C. A not-for-gain Group, https://tcxo-oscillators15936.blog5star.com/31404344/details-fiction-and-temperature-compensated-crystal-oscillators