ABC- regarding your FA data:
1) have you done any tweaking around your config wrt gain to increase range?
2) how are you seeing so far? I have a 1090 antenna in the attic ~ 8 m up and only see 100 miles ish out.
Yes, I have reduced gain to 38.6, but note that this is NOT the universal best best gain. The best gain depends on the environment in which antenna is located, and this is different for each installation.
Higher the gain setting, you receive distant planes whose signal is very weak due to distance. However higher gain has a disadvantage that nearby planes, whose signal is strong, saturate the dongle and the plane is dropped by the dongle. It is a compromise between far away planes and nearby planes, and depends solely on the user's choice.
Basically gain setting is trial and error. Start gain setting at -10, observe for some period, then reduce to 49.6, again observe for some period, then agai reduce to say 45 and again observe for some period, and so on till you ind a value which gives best results.
Your limit of 100 miles may be due to many reasons, like metal in the building material which shields antenna from radio waves, or poor quality or low gain antenna. Did you try to mount antenna on roof? That will considerably improve reception.