I did cut it to the airband. Dimensions i received from Martin are:
All elements 10mm diameter, impedance 50 Ohm, gain 4 dBd on 118 MHz, 6 dBd on 137 MHz. Gain is not very high due to very great bandwidth.
Mast as reflector, Radiator position 400mm, length 1136mm
Director 1 position 560 mm, length 1000mm
Director 2 position 960mm, length 940 mm
The receiver is only tuned to 118.2MHz, so maybe in the future i'll make a narrower bandwidth antenna, with a few extra elements to raise the gain.