Check with any amateur radio operator, UHF, VHF and above are line of site only. If bird drops below horizon or objects it will loose connection. I know of one university that is working on drones using HF frequencies (1-30 Mhz) and near vertical incidence ground antennas to communicate over the horizon. Only other way is a repeater in sky ala satellite in low geo stationary orbit. All space communication is done above 144 Mhz because signals do not bounce off atmosphere. HF frequencies will bounce or skip as off different atmosphere layers depending on time of day and solar cycle. Sorry for long post hope you get the drift of why you need altitude the farther out you do due to 2-5Mhz signals we use. Tim W4YN
Over the years my range has been decreasing with each home now blasting 2 or more APs creating unmanaged noise on this band. Before I could go out almost a mile, line of sight at tree top level. Now I'm hundreds of feet higher to clear the noise at 1/4 mi. I still enjoy the quick sorties and heading to the country for the range which is the reason why I haven't gone with a boosted yagi antenna rig yet. I'm fed up with this "off the shelf", unregulated band. Iv'e been debating on switching over my controller and bird to the European frequencies for "testing purposes only" out of curiosity. Yes, i know my app wont work and the fact its illegal broadcasting on this feq but so is putting an Evergreen amp on my CB radio, blasting through tube TV's with rabbit ear reception back in the day. You millennial's would know anything about that either.
It sounds like this person that's complaining about range is flying where he shouldn't fly.
Even if you are not a member of the AMA please read the flight rules because you are the reason why laws and regulations have been passed that limits our hobby.
I can't even fly FPV with a spotter anymore.
I used to fly 2 miles out via FPV while friend or one of my sons spots my.aircraft with binoculars. With the new regulations we can't do that anymore. Now the pilot has to have the aircraft in view with an unaided eye.
Laws like this were passed because of people, such as the one complaining about range in this thread. You are not supposed to fly in a suburban development, nevermind a congested area.