I personally wouldn't worry too much about the height.
The important thing is whether there are any obstacles nearby. So, for example if you have a station 2m above the ground, but nothing around it, then there are equations that you can use to convert 2m to 10m, or you can simply use the 2m. Likewise, if you have high buildings around it, then even if it is at 10m above the ground, it would be useless.