def make_reg_05h_byte(channel: int) -> int:
    """
    Make the byte for REG2 (channel)

    Channel control (CH) 0-83. 84 channels in total

    18 default for SX1262, 23 default for SX1268

    850.125 + CH *1MHz. Default 868.125MHz(SX1262),
    410.125 + CH *1MHz. Default 433.125MHz(SX1268)

    :param channel: The channel.
    :return: The channel / value for REG2.
    """

    if 0 <= channel <= 83:
        return channel
    else:
        raise RuntimeError(
            f"Invalid channel, channel must be between 0-83, but was {channel}."
        )