As art and rick said, the probe sounds off only at and around the tip. The probe has a range of about 3" if you're running Sens ~12oclock.
Also the Sovereign does not lie in All Metal. If you get a blip, there is something there. Disc can false off of iron to fool you. I always check what I think is something in Disc by using All Metal to pinpoint before digging.
Heres how I use the probe:
A) pinpoint by "X"ing the coil in all metal
B) flip to disc, flip to probe, and scan the spot
...1. if i get a signal with the probe, its a shallow object 1-3" therefore I'll cut a plug expecting to split the plug in half to get out the shallow thing. (you could use a coin probe/screwdriver to pry it up but I don't). if it nulls, its probably iron, so either pass or if the disc tone was just too good, dig it up and check the area again.
...2. if no signal with probe, its deep. so using the original pinpoint location I'll cut a plug ~4" across. when I pry out the plug I'll scan the hole with the probe.
......I) if I hear a strong signal, I've got it.
......II) if I hear a weak signal, I'll flip in to All Metal and pinpoint in the bottom of the hole with the probe. you can get a threshold change in All Metal from an object a little too distant to give a good Disc signal.
......III) if I null out, its iron, but maybe there is something else down there too? maybe recover it and then restart.
...3. if no signal on the bottom of the hole, check the plug possibly waving the plug over the coil to be sure. also use the tip of the probe to check the sides of the hole. if you get a signal goto I, II, or III.
...4. if nothing, dig another plug length out of the hole and rescan with probe. at this point you'll be at least 6" down (the length of a lesche digger).
...5. if nothing, its either really deep or the initial pinpoint was bad. Switch back to the coil and into all metal and pinpoint again. is it something tiny in the dirt you've already pulled out?
...6. if the pinpoint was bad and the signal is to the side of your plug, cut a new semi plug on the side.
...7. if you get no signal -- its either tiny shallow iron that you've bumped to the side somehow or its in the bottom of that hole so go to 9".
...8. if nothing -- either keep digging until you're tired or pack everything back in. go back to the coil and see if you get something now.
C) pile the dirt back in, replace the plug, and tamp it down with my
heel.
Most of my recoveries have been at 7" or less, so there might be some extra tricks for the 1' recoveries people sometimes talk about.
Hope this helps!