def ALMAGetBandLetter( freq ):
    """
    Return the project observing band letter from frequency

    * freq  = Frequency in Hz
    """
    if freq<117.0e9:
        return "A3"
    elif freq<163.0e9:
        return "A4"
    elif freq<211.0e9:
        return "A5"
    elif freq<275.0e9:
        return "A6"
    elif freq<375.0e9:
        return "A7"
    elif freq<510.0e9:
        return "A8"
    elif freq<730.0e9:
        return "A9"
    elif freq<960.0e9:
        return "A10"
    if freq<2000.0e9:
        return "A11"
    else:
        return "UK"