Rubber duck antenna gain
I recently came across this forum post, https://forums.radioreference.com/threads/rubber-ducked-db-gain.469533/
The discussion that a typical rubber duck gain is somewhere in the -20 to -10db range confirms a lot of what I already knew from a practical sense. It also lines up with my findings for the Antenna Hub https://strategicengineering.dev/antennaHub/
The antenna hub antenna doesn't have positive gain like a large vertical or yagi antenna. Its more that a stock rubber duck antenna has negative gain.