All the tunes use a single harmonic series. The bugle is a 1/4 stub transforming the impedance of the open air to the impedance of the lips. This will work at 3

All the tunes use a single harmonic series. The bugle is a 1/4 stub transforming the impedance of the open air to the impedance of the lips. This will work at 3/8, etc, so multiple frequencies are available.