> …seems we are both wrong.

If it makes you feel better to view an approximate number as wrong, then enjoy it. This is the internet after all.

I've personally had better results than that transmitting on a handheld set to 5w. There are a lot of variables to range on low power, small antenna units like this. Frequency, obstacles, characteristics of the terrain, condition of the antenna and connector, height above ground, background interference etc.

The best thing you can do to help yourself if you need to use one of these in the wilderness is to get as high as safely possible above potential receivers with it before transmitting. I.e. climb a hill or mountain with it if you want to be heard.

A neat trick if you have two decent handhelds and some rope: set one radio up to retransmit what it receives, tie a rope to its lanyard and throw it up into a tree branch as high as you can. With the other unit you can now transmit with your impromptu repeater being (hopefully) significantly higher up and giving you waaay better range. A decade or so ago I set up a very crude pair of solar powered repeaters like this in the mountains, it worked well and I was able to talk to people dozens of miles away on the other side of the mountains so long as I had LOS with the first repeater. The repeaters in trees at mountain peaks had massive transmit range even at low wattage. Not bad for some cheap Quansheng radios