Proper planning of the placement for your hub will greatly improve the Zigbee and Z-Wave™ radio performance. Check out this document before selecting the permanent location of your hub: Hub Placement Tips
Bobby , SmartThings publish a 3D polar map for their omni’ directional ZWave and ZigBee antenna. Could Hubitat perhaps do the same ? They are surprisingly directional both horizontally and vertically.
It would fit in with this placement category well.
I too would be interested in the radiation pattern.