Parts:
I started with a Bobcat300, located about 3 feet off the ground with the stock antenna in my kid's room, hardwired to my router. I was averaging about 0.03HNT a day.
I then used the same equipment, but put the stock antenna inside my house in the bottom right hand corner of the half moon window you see in the 2nd picture. I went to 0.25 HNT a day with that change.
Now I will run with this setup for a week or two to see what the change is over the internal antenna. Assuming it is the right direction, my next move will be to move this antenna mast up to the very tip top of my house, which you can see in the 2nd picture.
So if I see shorter 5.8dbi antennas then they are not truly 5.8? I've seen them in length from 16inches to 32 inches.
I bought this one and it came in a week: https://www.amazon.com/gp/product/B0927CGC76/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1