A method includes holding in a memory of a receiver, for each temperature in a range of temperatures, a respective first parameter indicative of a frequency error of a crystal oscillator in the receiver at the temperature, and a respective second parameter indicative of an uncertainty of the first parameter. An operating temperature of the crystal oscillator is measured. One or more frequencies, for initial acquisition of signals from a transmitter, are selected based on the first and second parameters corresponding to the measured operating temperature. The receiver is tuned to receive the signals from the transmitter on at least one of the selected frequencies.