Upgraded antenna from 1.2dbi to 5.8dbi and... no noticeable change... (sad trombone)

Hi all - wondering if you could offer some suggestions of things to try. I have a FreedomFi miner and it comes with a 1.2dbi antenna. I live on the edge of a fairly populated area, so one direction is farm land (no occupied hexes) and the other direction is a fairly good sized town with lots of occupied hexes. After running for two weeks, I'm only witnessing people 1-2 hexes away, with 4, sometimes 5 witnesses over the past 5 days.

I upgraded to this antenna I got on Amazon (only after purchasing that did I realize I should have just gone with a RAK or other reputable brand).

Anyways, I turned off the power to the minor, swapped out the antenna, which is on the third floor of our townhouse (inside, close to the ceiling, near a skylight window). Turned the power back on and let it do its thing - and I'm still only connecting to the same 4-5 miners in my area.

So, the antenna is working since I'm still getting witnesses, but I'm just surprised it's no more effective than the 1.2dbi antenna. Is there something else I need to do or something I can try? Should I just chalk it up to having bought an antenna of dubious quality?