Same Setup/location total different results

Did you try Quick Spider?
It costs pennies, and is easy to make.
It may possibly improve. No harm in trying.

The only drawback is that you will need a pigtail or adapter to connect RG6 coax to your Dongle:
F-female to MCX-male for generic DVB-T
F-female to SMA-male for Flightaware ProStick.

F-male to MCX-male Pigtail

F-female to SMA-male Pigtail