Range


#1

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?


#2

#3

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