Iffy Signals G M Doc Watson
  Metal detecting today differs very little from years ago.  Some people hunt the beaches for Spanish silver or the rings of yesterdays’ swimmers; others look for coins in the local parks or the long gone fairgrounds.  And others hunt the fields, forests and latest construction sites for relics of the early wars and the settlers who waged them.  Some manage to do a little of it all.  What has changed, however, is the equipment that we do it with.
  Starting in the early seventies with a Compass 66B, detecting was a simple process.  The detector had an on-off/volume knob, ground balance knob, small green light and a switch to change the signal indication from sound, light or both.  You turned it on, tuned the ground balance to neutralize the effects of ground mineralization, and dug every single waver to the threshold tone.  A loud signal could be a bottle cap on the surface or a hub cap two feet deep; there was no discrimination and other than loudness/weakness, little change in the tone.
  I remember detecting a park that first year out, and digging two or three aluminum pull tabs in a row.  The next signal was exactly the same and I would have bet money it was another tab.  But I was surprised when I popped up my first silver dollar, together with a couple of mercury dimes.  That told me that it all pretty much sounded the same so I’d have to dig it all.
  Over the years detectors have improved their performance and offered new capabilities.  Listening to the subtle changes in tone one could hear a difference, to some degree.  At least a bottle cap and hub cap no longer sounded the same.  At a gold mining camp I could tell the difference between metal objects and the mineralized rocks that were in abundance on the site, by the quality of the signal tone.  One produced a clear, crisp tone where the other signal experienced a slight delay, giving it a re verb effect.  Though I’d dig the odd sound every so often as a way to double check and keep myself honest, this tonal discrimination allowed me to skip over 95% of the signals I was getting and to focus on the clearer metal signals.  That first day yielded over an ounce and a half of small gold nuggets, including one that weighted a half ounce.
  On the next day the good signals were far and few between, as I was now covering the same area again.  One signal sounded iffy, neither good nor bad, so I decided to check it out.  I quickly located a hot rock responsible for (at least) part of the signal; there was still a weak tone there.  This tone sounded more like the metal signals I had been digging and as I dug deeper and deeper, it grew louder and stronger.  At a depth of two feet I located the source of the second signal, a palm sized hunk of gold that weighed over five ounces.
  Many years and detectors later, the same concept holds true.  Between multiple tones, conductivity and ferrous vs. nonferrous indicators, my detector displays more information then ever.  I just need to interpret it.  Most sites I detect and dig most all metal,
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 though I will fore go small iron objects.  One tone sounded like the target could be a bit of small iron, and the secondary screen information suggested the same.  However, since there was not much “new trash” on this site, I dug the iffy signal and was rewarded with not one but two metal objects, a square iron nail, and an 1850 O dime.  Another broken signal in the same area turned out to be a much worn 1803 half reale.
  It could be easy to let the technology overwhelm us when we first start out, or when we change to a new detector; partly because detectors are so much more accurate then before.  Now when the screen says 10¢ clad, it most likely will be; but not always.  If someone is working a heavily trashed area, relying on the detector to decide dig/not dig may be the only way the site is worth digging.  But in areas where the finds could be very rewarding, and it is not carpeted with modern trash, digging the extra trash could well be worth the efforts of chasing the iffy signals.
  Another such time occurred a few years ago while covering the yard of a residential home lost to the construction of a highway by-pass.  I