shuptyler -- tough question to answer, since it's tough to know what was going on for sure not being there. A couple things...YES, if there is trash, the "repeatability" of the target's response can -- and often will -- be less consistent. Secondly, if you are running too high OR too low of sensitivity, that can affect the tone (depending upon the amount of trash in the ground, and the amount of mineralization in the soil). Being new, I assume you are running semi-auto sensitivity? If so, that's good, but deeper targets won't be quite as repeatable often times, when running semi-auto. When you learn the machine well enough, running manual sensitivity will help the deeper targets to hit more consistently -- but will also result in more "falsing," so it's a tradeoff. It's best to stick with semi-auto for awhile, until you gain enough experience at understanding how a "good" target sounds, vs. a "bad" target.
Have you learned to do the "Minelab wiggle" yet? Obviously, when hunting, you will hit many targets on your "normal" sweeps of the coil that catch your attention. Once I get a signal that interests me, and I have narrowed down the location of the target, I then begin to "interrogate" the target using the "wiggle"...meaning, I cut my sweeps down to little, short, fairly rapid, back-and-forth swings -- like maybe 4-6 inches on either side of the target (i.e., the "Minelab wiggle"). As you do this, repeatedly, the machine will either tend to "lock on" to the target (if it's a "good" target), and start giving a good, consistent tone, OR, the tone will remain more choppy and inconsistent (if it's a "bad" target -- or occasionally also if it's a good target, but one that is almost undetectable due to co-located trash). When doing this "wiggle," rotate slowly around the target 360 degrees, while constantly maintaining that "wiggle." THIS, to me, is the key to deciphering targets with the Explorer. I consider it a two-step process...regular, slow sweeps to give you that initial hint that a potentially intersting target is under the coil, and THEN the "Minelab wiggle" while circling the target, to "interrogate" the target and make your dig vs. no-dig decision. LISTEN CLOSELY to what you are hearing while circling the target while "wiggling" it, and then make note of what type of target you recover. Over time, you'll learn what types of information you get from this process that mean "good target," and what types of information usually mean "trash target."
Hope this helps...
(and yes, you are doing VERY well, so far!)
Steve