Crossbow Classic PI SAT

[TowySalmon]

On the Crossbow Classic, what is the purpose of the SAT pot’ and how does one use it? The detector will be used on beaches primarily for jewellery but it two locations looking for Spanish Cobs and Gold Doubloons.
Please be aware, I have no technical knowledge, so a simple explanation would be appreciated especially when explaining the use of the SAT pot'.
Thank you.

[Qiaozhi]

SAT stands for Self Adjusting Threshold.
Its purpose is to maintain a steady threshold as the dc level will tend to drift over time mainly due to temperature.
If you keep the coil steady over a metal target it will eventually adjust the threshold and effectively tune out the target.
Because of the SAT you need to keep the coil in motion, and the pot adjusts how fast the threshold is adjusted.
The Crossbow SAT can be changed from very fast to very slow.

[Carl-NC]

To add to that...
A faster SAT retune can help with the "breathing effect" you can get on sloped wet salt sand (you'll know it when you hear it). However, a faster SAT can also reduce depth on targets. I generally recommend running it as slow as conditions allow.

[TowySalmon]

Thank you both very much for the information.
Does the knob have an off/on? When the knob is turned fully anticlockwise there seems to be a little resistance between the two points in the pictures, samely, when moving from fully anticlockwise clockwise there is again a feeling of an off-on occuring.
If it is an off/on should I use the detector in fully anticlockwise (off), or just past point of resistance (on) as in picture 2? Or turn the knob to somewhere else?
I would say that the beaches I detect are quite flat.
Thanks in anticipation.

[GeoMax]

Hi,

yes, the auto-track poti of the Crossbow Classic has an on/off switch.

[Qiaozhi]

The Auto-Track (SAT) control does not have an on/off switch. There is a Static/Dynamic switch on the rear panel which changes the setting between slow and fast modes.

AUTO-TRACK
In association with the STATIC / DYNAMIC switch on the rear panel, the AUTO-
TRACK control adjusts how fast the detector tracks the threshold level. Slowest
tracking occurs with the control at minimum (fully anti-clockwise) and conversely
the fastest tracking occurs when it is set to maximum. Initially try setting the AUTO-
TRACK control to about 7 o'clock. This provides good separation between targets
while allowing the coil to be swept back and forth at a reasonable speed. Again, you
should experiment to see what works best for you.

STATIC / DYNAMIC
For normal detecting it is best to work in DYNAMIC mode, which provides a self-
adjusting threshold. The speed of this adjustment can be altered by the AUTO-
TRACK control on the front panel. In practice this means that you must keep the
coil moving. If you hover over a target, the audio tone will automatically adjust
itself. A STATIC mode is also provided to allow the user to pinpoint difficult targets.
Be aware that this is not a pure STATIC mode in the usual sense. Some PI detectors
do not provide auto-tracking and work only in STATIC mode, requiring the user to
frequently push a reset button to retune the threshold. Crossbow Classic PI also
provides auto-tracking in STATIC mode, adjustable by the AUTO-TRACK control
on the front panel. However, the tracking speed is extremely slow, allowing more
than enough time for pinpointing. STATIC mode can even be used for general
searching if desired. The advantage of this quasi-STATIC mode of operation is that
the threshold is maintained over time and does not diverge from the default setting.
Hence there is no requirement for a reset button. In reality you could consider the
STATIC mode to be a very slow version of the DYNAMIC mode.

[GeoMax]

Hi Qiaozhi,

you are right. I must have mixed this up with the Hammerhead circuit because both circuits are very similar. In the Hammerhead was an on/off switch.