def build_splat_el(transmitter):
    """
    Return the text (string) content of a SPLAT! elevation file (EL file) corresponding to the given transmitter.

    INPUT:
        - ``transmitter``: dictionary of the same form as any one of the elements in the list output by :func:`read_transmitters`

    OUTPUT:
        String

    NOTES:
        A transmitter with no ``'bearing'`` or ``'antenna_downtilt'`` or ``'vertical_beamwidth'`` data will produce the string ``'0  0'``.
    """
    t = transmitter
    try:
        bearing = float(t['bearing'])
        ad = float(t['antenna_downtilt'])
        vb = float(t['vertical_beamwidth'])
        s = '{!s}  {!s}\n'.format(ad, bearing)
        counter = 0
        for x in range(-10, 91):
            if counter < vb:
                s += '{!s}  0.9\n'.format(x)
            else:
                s += '{!s}  0.1\n'.format(x)
            counter += 1
    except:
        s = '0  0\n'
    return s[:-1]
