The answer is in fact 41, or How to get 35:1 bandwidth from a cone antenna

The design and optimization of a conical antenna above a ground-plane for RFI monitoring are discussed with a specific focus on impedance matching to 50 ohm. Simulations using the computational electromagnetic code FEKO were used through iterative analysis to change the cone angle and cone apex height above ground-plane level. The optimized antenna design with cone to ground-plane angle of 41 degrees and cone apex at ground-plane level was manufactured and achieved a measured −10 dB impedance bandwidth of 35:1.