EARFCN Calculator calculates LTE Download & Upload frequency from EARFCN DL value. And vice versa. ARFCN (Absolute Radio Frequency Channel Number) – An ARFCN defines a pair of Radio frequency channel frequencies for uplink and downlink use. This tool is useful for 3gpp developers and testers. Features: DL/UL Earfcn Calculator. DL/UL Frequency Calculator.