The higher the Fe value the more likely it is iron, the more the Fe jumps the more likely there are varying targets in the ground of which at least one is iron. Dig a few jumpy targets in the area you are hunting and then decide how much digging for iron you are willing to suffer. You can usually eliminate elongated iron since it is sensitive to the coil orientation and will cause the detector to null in one direction (long length sweep) but not in the other (if isolated from other elongated iron).
A coin amongst iron is likely to only signal in one very restricted sweep angle - if at all. As a rule to keep your sanity in fields of iron, just search for that one repeatable stable hit and ignore the rest. It may only be a sweep length of 2-3" in only one very precise angle - but if you find it - dig it. Consider all targets with Fe values below ~25 (iron up averages the Fe value in iron so good targets can be found in iron field with higher Fe values). Just look for stability more than target value.
Since it is tiring to watch the display, I just hunt in Combined (3030) or TTF (E-Trac) so that a med-high or higher audio (Co value) will sound for anything around the 12Fe line (+/- 3) with the 3030 or above ~20Co (with E-Trac). I'm only listening for the med-high or greater tones that repeat (not interlaced with low tones). That makes life simple. Of course if you want rings and jewelry (which will be in the 1-15Co area around 12Fe, you'll have to watch for them too. With the 3030 I give that area a unique bin tone in combined and with the E-Trac in TTF it gets a unique tone too (usually a med-low tone). I reserve the lowest tone for iron (above ~25 in combined).
If the iron is especially dense and the CTX/E-Trac is nulling left-right-and center, remove all DISC (or almost all). Otherwise the machine will be nearly completely dead to low conductive targets. You won't find rings and jewelry in fields of iron (nails) with globs of DISC dialed in - the extra filters greatly decrease sensitivity in both machines (unless the jewelry is thicker or larger and therefore higher conductive). The FBS low freq was chosen by design to minimize reaction by low-conducting iron - but it will also cause low-conducting rings to be passed. Low freqs don't build strong secondary fields on poor conductivity (high resistive) surfaces (like iron and thin rings). The higher harmonic of the FBS helps to induce voltage across the target, but the xmit field is not as strong as the primary freq (FBS compares only low/high freq response at several varying pulse lengths and measures along at several points along the time constant of target's decaying field).
If you use the E-Trac/3030 in dense iron fields, you need a smaller coil (less soil volume), slowed sweep (more time to resolve target), varying sweep angles (to escape iron nulling), and a careful ear to hear those med-high/high peeps (which are not tonally the same as iron falsing - iron falsing is erratic/truncated blips that do not repeat unless coil sweep is exactly duplicated - caused by sharp points/bends on iron targets presenting a conductive point. Unless the coil sweep angle is duplicated precisely the next sweep will be off just enough that eddies are not strong on those prominent points. In dense iron fields a variety of iron will be chirping falsely (at various depths), thus the need to control the sweep angle to uncover only repeatable signals that occur along set sweep angles). Iron falsing is common, as strong Fe responses will drive the Fe value through 35Fe into the next bin 01-03Fe (which is usually tonally set higher for other reasons and produce the chirp). You can use a slight bit of DISC in that area on the E-Trac/3030 to limit the falsing (a good idea).
Since the E-Trac is not well balanced, constantly attempting to control an exact sweep angle over a suspected good signal (clean med-high/high beep) will tire your forearm out, especially with the11" DD coil. Another reason to use a smaller coil. The E-Trac is best in open fields where wide swings can be made - it is not made for close/tight work, like iron fields. But even so, it can produce good targets - just need to learn to discern that beep amongst the falsing chirps (and develop stronger forearm and shoulder muscles - actually learn to use your wrist to control small movements and give your arm a rest. I also have learned to hunt ambidextrously to rest the arm).
Note: If you dig past the reasonable depth given on the meter for coin-sized targets (you did check the meter before you started digging didn't you?) your probably not digging a coin-sized target. It is probably a nail (ferrous provides strong return signal that enhances the weak conductive response from the nail head/tip). You will find elongated iron at great depths (12-15") and in the side of the hole (you are likely digging toward the nail tip). If you go much past the depth meter's reading - but your pinpointer (in all metal) says the signal is deeper - it's a nail (or crushed soda can). Skip it - it isn't buried pirate treasure, it's junk.
If you want to find the jewelry/rings - dig all targets along the 12Fe axis, even if they are reading 01Co. That foil is just as likely to be a ring (especially if the depth meter is > 2-3", beyond most foils' depth). There's not much 'easy' about metal detecting.
Johnnyanglo
Your bit about Iron-Falsing is more applicable to the more pressing questions and issues I have been experiencing. I have brought up other threads/posts trying to get answers. I hope your information will help me single out those false signals. In fact everything you mentioned is useful and I will be taking note of it. Thanks again. 