Hi Kos,
I don't know which is worse, very wet ground or very dry ground
Very wet ground just enhances the conductive properties of everything and it can get really noisy if there are many targets close together. Considering the F5 will pick up BB's, small foil bits as well as the normal larger trash items like tabs, crown caps and all that other metallic junk that winds up on the ground, plus add in any EMI floating through the ether around you and it can get a bit crazy at times.
Just remember that the site conditions determine how hot you can set the machine. You basically have to ignore how anyone else can set their detector for their site and just focus on how best to set up for your location. Sometimes you can hunt with high settings, sometimes you can only hunt with low settings. The site conditions always have the last word.
First thing is to determine if its EMI or ground noise causing your problems. Hold your detector up in the air. Are you getting chirps and jumping numbers on your display? If so, thats EMI and you need to turn your Gain or Threshold levels down. Once you get it stable in the air, then sweep it over the ground. Now all that noise and jumping number are ground related. Here you can do several things. One is that now you can set your disc or notch to eliminate some of that noise and numbers. Raising the disc to the top of foil will help a lot, notching out tabs will help alot, and if you have a lot of large rusty iron like the bolt you mentioned, notching out the 50c segment will help a lot. The key to happiness is to limit the audio to a comfortable level your brain can process. As you get more accustomed to the detector you can let in more objects.
Key thing about the Gain and Threshold controls. The Gain makes the signals bigger or smaller. Like a . vs a O. But remember it affects all signals, good and bad. The Threshold control does two things. From -9 to 0, it raises or lowers a internal trigger point or threshold. Turning the Threshold down to -9 raises the trigger point so that only signals of a certain strength can be heard. Raising the threshold towards a 0 setting lowers the trigger point, making it possible to hear the weakest of signals. Another words, the threshold settings from -9 to 0 are a form of signal strength discrimination. Lower settings toward -9 require a stronger signal in order to be heard, higher settings toward 0 require a weaker signal strength to be heard. Threshold settings from +1 to +9 enhance the volume of the signals. Another words it makes weak signals louder.
So at your setting of 50 and +1. You have multiple the signal strength of all targets relative to the 50 gain setting, have lowered the threshold trigger point to 0 so that even the weakest signals can be heard, plus increased their audio loudness with the +1, and doing it in really wet ground which in itself is enhancing the signals. Add in the actual ground content and yep, it could be noisy.
That knowledge should help you figure out the right settings for your different ground conditions.
Good luck and HH,
Mike
