I will assure you, FIRST and foremost, you need to get to know the nuances of any machine. You have to "pay your dues" so to speak. You will find surface or near surface coins if any are present. The deeper ones, you will also find, after you learn the ETRAC better.
You look like a young fellow, and I don't have a clue how long you have been detecting. I have been doing this for 37 years, and I can assure you that with any given machine, my silver coin score has gone up with the amount of time I have had a machine.
The ETRAC is a stellar producer. Period. With time you will find, not only silver, but more than with other machines, imho.
The first thing you need to do, is to use one program, and dig a LOT of signals. DON'T get in a hurry with learning, and I think, instead of trying all the TTF, Different Patterns, etc, learn what the machine is saying to you. PLANT a test garden for sure.. At 100 hours in time used, you will see a marked increase in recovery I predict, if you learn the machine. There are so many tricks with any detector, to learn. With my ETRAC, I hear buzz, static, thumps, roundness of signal, abruptness, whispers, and other subtle sounds, that all are clues as to what is there, and what the ETRAC is saying to me. The height of the coil off the ground, while still sounding, will tell you how big the target is, or isn't. Using the edge of the coil can tell you information, as can speed of sweep, both on an already found signal, or just sweep.
There is NO quick and ready answer to finding all the stuff others miss. Speed, direction of sweep, moisture of the soil, length of time an item is buried, electrical interference, and experitise of the operator all play a role in recovery. A blind hog can still find an acorn as well, so things will pop up, occasionally. (My recent find of my 1807/06 overstrike one cent piece could have been found by a blind man with a radio shack detector, as it was only 4 inches down, and nothing but soil around it. ) That being said, there is simply no substitute for experience with your machine. DON'T give up on it. DON'T get in a hurry with it.
I just spent a couple of days, hunting an old church from the 1800's, which was torn down in 1956. I have taken 4 Mercury dimes out of here, and the newest wheats have been 1942 (only one) The rest of the coins have been in the teens. The dimes were at an honest 8 or 9 inches, and rang solid with the ETRAC, is manual sens at 27, multi, and the old park pattern. Since the dimes are there, I can reasonably assume there are other silver coins there. There should be some barbers/seated. I can further deduce that they are likely to relatively deeper, up to 12 to 14 inches, which is beyond my depth capabilities with the machine I suspect, even with my 15x12 SEF. I am going to try my WOT next time out, just to see if it reacts differently, and simply dig anyting beyond 6 inches.
I have wandered a bit on this post, but my advice, is slow down your speed, and slow down your changing modes, and above all, slow down your learning process, and you will indeed find the stuff that others have left. Finally, as another post in this thread alluded to, use your head, and look places that might be overlooked by others. When you get a goodie, search a circular spiraling pattern around it, in case the same person lost more stuff at the time......
HH
Dennis