Opening it
PKT → Fox hunt, or the menu of the new intercom look → Fox hunt. Tune the fox's channel first: the hunt listens on the current channel.
The readout
The big number is the signal strength in dBm (higher, closer to zero, is stronger), with the S-meter and the peak since you opened it or cleared. Beeper on clicks through the phone faster and higher as the signal rises, so you can hunt without looking. Pointing shows the compass bearing of the top of the phone, corrected to true north.
Marks and the estimate
Hold the phone against your chest and turn slowly: your body blocks the signal from behind, so the strongest reading is when you face the fox. Point the top of the phone that way and tap Mark: the reading, your position and the bearing are saved. After two or more marks from different places, the app works out where the bearing lines cross, giving stronger readings more weight, and shows the distance and direction from you; the plot shows your marks (cyan weak, amber medium, red strong) with their bearing lines and the estimate as a green ring. Without bearings, the strongest mark is the hint. Open in maps shows the estimate in your map app. Marks stay until Clear marks, even if you close the sheet.
Close to the fox
Near the transmitter every reading is at the top of the scale. Off-frequency listens 10, 20 or 30 kHz above the channel, where the fox's signal is much weaker, so the readings start to change again as you move. Closing the sheet tunes back to the channel.
Be the fox
Start the fox beacon sends 5 seconds of beeps on the current channel every minute until you stop it or change channel; on amateur channels your callsign follows in Morse. PKT lights while it runs. Hide the phone, with a full battery.