Here is a little sample of the detail on the site:
CTX 3030:
DETECT Screen (page 7 of the CTX-3030 Instruction Manual)
The CTX-3030 does not have either a Pattern Screen or Digital Screen. All visual information (Discrimination patterns, Target's FE-CO coordinates, etc.) is presented on the Detect Screen which can be accessed at any time by pressing the Detect button.
The FE-CO numbers and Target Depth readings can be shown in large sizes if a large format of the Target ID Panel is chosen through the Display Menu (page 46 of the Instruction Manual). The large Target ID Panel will only appear on the Detect screen when a target is detected.
Just like on the E-Trac's Pattern and Quick Mask screens, on the CTX-3030 Detect Screen, a Target Cursor (Target Cross Hair) of "Accept" or "Reject" type is positioned in relation to the FE-CO properties of a detected target: the cursor takes the same spot where it would be on the E-Trac screens.
For example, when the CTX-3030's Audio is set to "50 tone CO", and the the low Co (Conductivity) readings correspond to Low tones, the Target Cross Hair moves toward the left of the Smartfind 2 window. When the high Co readings correspond to High tones, the high-conductive targets cause the Target Crosshair to appear toward the right of the window. Thus, the Co readings range from 01 to 50 on the horizontal axis of the Smartfind-2 window.
In FE tone 35 mode, Fe (Ferrous) coordinate readings range from 01 to 35 on the vertical axis of the Smartfind-2 window, and the FE tones range from the LOW "blaats" (a Target Cursor is positioned on the bottom of the Smartfind-2 window) to HIGH-PITCHED "Squeaks" denoting non-ferrous targets with a low Fe number (a Target Cursor is positioned on the top of the Smartfind-2 window).
Unlike the E-Trac, the CTX-3030 is equipped with two great features - TARGET TRACE and TARGET TRACE PINPOINT (activated in the Detect Screen Quick Menu, page 11 of the Instruction Manual), which are displayed over the Discrimination pattern.
TARGET TRACE shows a real time animation of detections per second that the CTX-3030 detector uses to identify a target, and travels between the FE-CO coordinates of detected targets shown on the screen. This is particularly useful when detecting targets lying in close proximity to each other or in cluttered environments. You can easily identify and isolate individual targets by using the TARGET TRACE display (page 11 of the Instruction Manual).
There are four types of the TARGET TRACE visual "paths":
1) Horizontal Trace indicates coins of LOW and HIGH CONDUCTIVITY.
horizontal Trace on CTX 3030 Detect Screen
2) Vertical Trace indicates the HIGH-CONDUCTIVE coins and FERROUS junk.
Vertical Trace on CTX 3030 Detect Screen
3) Diagonal Trace indicates the LOW-CONDUCTIVE coins and FERROUS junk.
Diagonal Trace on CTX 3030 Detect Screen
4) Erratic Trace (it looks like a bland splotch on the display) indicates the RUSTY JUNK.
Erratic Trace on CTX 3030 Detect Screen
Also, unlike the E-Trac, the CTX-3030 is a "visual detector". With the color graphics on the CTX 3030 display, you are better able to observe and follow the trace path of a target and determine its signal strength through the color-coded graphics. However, the TARGET TRACE feature is effective only down to 7" (≈18cm) in depth, and, for targets lying at greater depths, one barely gets any visual indicators. The TARGET TRACE PINPOINT may perform better and should be used in this case.
As for dealing with QUESTIONABLE responses, the CTX-3030 has more effective "tools" than E-Trac: "COMBINED" Tone ID Profile, "FERROUS-COIN Target Separation", Target Trace, and Target Trace Pinpoint.
SENSITIVITY - AUTO (pages 54-56 of the E-Trac Instruction Manual)
With this setting, the Sensitivity level is just a little above the 'Suggested' Sensitivity level.
CTX 3030:
SENSITIVITY - AUTO (page 21 of the CTX-3030 Instruction Manual)
Auto Sensitivity level is shown by the white number (left number) on the Sensitivity Panel optionally displayed at the bottom center of the Smartfind-2 window (pages 19, 21, and 46 of the Instruction Manual). If Manual Sensitivity is ON, this number will also represent its level that you have set. The green number on the right of the Sensitivity Panel shows the 'Suggested' Sensitivity level.
Do not use Auto Sensitivity at the beach.
Unless I metal detect on the low-mineralized or NEUTRAL ground, I do not use Manual Sensitivity to allow the detector to respond to deeper and small targets lying within detecting range. Instead, I utilize less discrimination and receive more signals, most of them being true signals emitted by the accepted targets. This way I can "see" what lies underground and avoid being bugged by false signals caused by iron junk and/or high mineralization. Also, when I compared these two approaches to increasing the detector's "sensitivity", "Maximizing Manual Sensitivity" and "Lowering Discrimination", through testing, the latter gave me greater results in the high-mineralized ground.
In AUTO mode, E-Trac (or CTX-3030) continually analyses the ground and adjusts the Sensitivity level when the ground mineralization level changes. One should keep in mind that the ground mineralization level changes more often (sporadic mineralization) at the former settlement sites located in the never-plowed areas than at the sites located in the plowed fields (where all cultural layers and "mineral pockets" have been uniformly mixed up).
So when you hunt in the never-plowed area, you should always run your E-Trac (or CTX-3030) in Auto Sensitivity to avoid jamming its microprocessor, which will cause a substantial loss in operational depth range. To learn how the Sensitivity settings affect the detector's performance, read about it on page 1 of my article - How To Search Around Cellar Holes Successfully.
If you hunt in the plowed fields, and the ground is not highly mineralized, and the area has been cleaned of most superficial junk (and good targets), and you wish to switch Sensitivity to Manual (page 56 of the E-Trac Instruction Manual, page 21 of the CTX-3030 Instruction Manual), the 'Suggested' Sensitivity should be used as a guide in setting the Manual Sensitivity.
To get more detecting range while hunting in areas with low trash, Manual Sensitivity should be set in the 23-25 range for so-called "depth boost" to come into effect. However, if the medium-to-high levels of mineral content in soil do not permit utilization of Manual Sensitivity setting above 23, and you still set the Manual Sensitivity much higher above that point, you will risk running your detector not being properly adjusted to the current metal detecting conditions.
Also, with Sensitivity being set too high, correct identification of target properties is negatively affected by instability, in particular, of Fe numbers in the target's FE-CO read-outs. Especially this concerns identification of deep coins lying close to iron objects. In this case, the Fe value of a deep coin may bounce within the Fe 17-27 range, sometimes reaching even higher numbers, when the coin's signal gets affected by nearby iron junk. This is why the Fe values are not considered reliable and should not be used for identification of deep coins. In the same case, the Conductivity values are more stable and must play a major role in determining the non-ferrous target properties (read more details on questionable signals here).
You can also adjust Manual Sensitivity to the highest level of stability through manual selection of a channel with the least noise (page 75 of the E-Trac Instruction Manual, page 20 of the CTX-3030 Instruction Manual). However, if you set all three internal signal channels to the same high level, the magnetic ground interference may cause false signals and unstable Target ID (the FE-CO numbers will be bouncing all over the Smartfind window). Also, in Auto Sensitivity, any Minelab's FBS detector is able to detect at a higher sensitivity level than you are able to achieve for the same noise level.
The Manual Sensitivity can be effectively used for gaining more operational depth range only when:
1) the ground is NEUTRAL or has a very little mineral content;
2) the iron junk is sparse in the ground;
3) stable audio Threshold can be maintained;
4) you metal detect in the grass-overgrown area, and you do not have a larger search coil, and increasing the Manual sensitivity is the only way to get to shallow coins and artifacts;
In any case, remember that an amount of deep targets to which the detector is allowed to respond is inversely proportional to the Discrimination level - a key factor unlike Manual Sensitivity.
AUTO SENSITIVITY LEVEL - A (page 55 of the E-Trac Instruction Manual)
CTX 3030:
AUTO SENSITIVITY LEVEL - A (page 21 of the CTX-3030 Instruction Manual)
The Auto Sensitivity Level allows you to be more conservative or aggressive while operating the CTX-3030 in AUTO Sensitivity. Increasing this level by +1, +2, or +3 sets the Auto Sensitivity higher on each of three internal signal channels (high, medium, and low - all helping identify targets correctly) than the automatic setting by the number of levels you select. However, increasing this level will also cause a few more false signals and decrease the accuracy of Target ID's. Decreasing this level by -1, -2, or -3 will have opposite effects on performance of your CTX-3030.
Some detectorists utilize level "+3" to detect faint target signals, but it is a "catch-22" as more false signals will appear. And certain types of small and thin hammered coins are left undetected when the "+3" level is used because of affects of high mineralization. The "A" setting allows me to find not only the smallest hammered coins of 5mm in diameter, but also tiny fragments of other hammered and thin milled coins