Interesting discussion... as it happens, I have the FMKit beacon and recently bought the older Baofeng UV-100 radio to locate the beacon. Previously I'd used a Motorola Talkabout 4600 radio but it doesn't have a removeable antenna or squelch, so I was having problems using it to locate the beacon.
Although I have no doubt that the FMKit can be used to locate my Phantom, focusing the search continues to be a challenge. You do this by intentionally blocking/attenuating the signal received from the beacon by your radio. Peter, the developer, told me to use my body and to spin in a circle with the radio held against my chest. Unfortunately I have a balance problem and can't do that without falling over
Other methods include wrapping the radio in aluminum foil, removing the antenna, adjusting squelch, and even putting the radio inside a tin can.
By the way... if you remove your radio's antenna DO NOT TRANSMIT or you'll fry it, just as I fried my FPV tx by forgetting to connect the antenna.
So... I was about 800 feet from the beacon in heavy forest and got a weak single tone signal, repeating every several seconds on my radio (I use channel 5). As I move closer to the beacon, I begin to get two tones... then three. To focus the search I need to identify the direction which gives the strongest, clearest tones and move toward the beacon.
It obviously takes practice.
Advantages -- I live far away from cell phone service and seldom fly in open areas, so this is my only realistic hope of finding a "Phantom in a haystack". Also, the beacon and its tiny battery are ridiculously small. I put it in a small pill bottle and fix it to the Phantom's landing gear with Scotch tape.
If I know that I will be flying where there's cell service, I'll be using the FiLiFi GPS locator with an AT&T sim card. Cheaper annual cost than the Garmin and similar GPS units.