ADSB aircraft simulation

Hi,
I would like to enable simulated vehicles in my simulation, to see how my vehicle reacts based on ADSB settings. I have found this documentation ADS-B — Copter documentation and based on the second video the SITL shall allow to simulate manned aircrafts. I have set the SIM_ADSB_COUNT to 20 and other params connected to this, but I dont see any manned aircraft on my map, there are no vehicles flying around.

Do I miss something? I am unable to find any documentation to sim_adsb params, which are in my drone. I run 4.5.0-dev. Do I need any piece of HW to simulate the traffic?