Range

[W1MDS]

I am new and my best range so far is 217.2 miles alt of 45k. Is that my limit at 80 feet above sea level with some trees?

[rugomol]

What is the Maximum Range I can Get?

INTRODUCTION The Maximum Range achievable at any location depends on (1) Curvature of earth (2) The terrain around that location. Terrain plays a very important role as hills & changes in ground level will restrict maximum range. This is due to the fact that propagation of radio waves in GHz/Microwave range is line of sight. The range is therefore limited by curvature of earth, and is about 250 nautical miles / 450 km for an ideal condition of perfectly level terrain. Hills & rise in grou…

[evangelyul]

Yes, according to [http://members.home.nl/7seas/radcalc.htm] for a totally obstacle-free horizon (rare !). [https://www.heywhatsthat.com/] can give you a more accurate answer including the obstacles in your area.
according to the numbers you provide, and the calc result, the difference can be attributed to
a. obstacles
b. antenna quality

HTH
Evangel