I work for an event on a 60-hectare site with a few hired vehicles (trucks, forklifts etc). The site is a couple of miles/kilometres across.
The problem is locating vehicle keys. Dipshits take the forklift and wander off with the only key. We need to be able to locate the keys.
Range is far too long for Bluetooth.
Money is tight, lol. Subscription services are probably not viable, we prefer an upfront cost. That rules out GPS trackers that update their location via mobile cell services.
Is there any beacon on the market that can be picked up at a couple of kilometres and costs a few hundred euros for a set of, say, six beacons?
Closest thing I can think of something using GPS and radio communication, but the only context I've seen or looked for it in was for finding rockets. I recently bought a kit from eggtimerrocketry.com that does not require a radio license, but there are also systems out there that require a 60mm HAM radio license. These may be too bulky or take too much assembly for your need though, and I'm not sure about battery life as they are intended for relatively short rocket flights.
The loko beacon posted by someone else looks to be similar and pretty good, not sure if it uses the same tech or not tho.