Need help with sand shark

KRILL

Greenie
Aug 6, 2014
17
4
TEXAS
Detector(s) used
AT PRO
Primary Interest:
Metal Detecting
I just got a new TESORO SAND SHARK and went to the beach yesterday with it. I only hunted the water for about 3 hours. Sometimes the threshold surges up and down even when the detector is not moving. I was still able to find targets but could not find a way to stop the threshold from surging. The cable is secure to the shaft. I tried the normal and vco mode and adjusting the pulse and threshold settings. This was at Galveston beach. Is this normal or am I doing something wrong? No power lines or other detectors around.
 

Terry Soloman

Gold Member
May 28, 2010
19,410
30,023
White Plains, New York
🥇 Banner finds
1
🏆 Honorable Mentions:
1
Detector(s) used
Nokta Makro Legend// Pulsedive// Minelab GPZ 7000// Vanquish 540// Minelab Pro Find 35// Dune Kraken Sandscoop// Grave Digger Tools Tombstone shovel & Sidekick digger// Bunk's Hermit Pick
Primary Interest:
Metal Detecting
FIRST, go back to page 12 in the manual and MAKE SURE you have set your tone frequency to match YOUR hearing the best. Do you hear high or low tones better? Next, set your pulse width to about 3/4 power (2-230pm position). Turn your threshold up to where you can barely hear it above the waves and wind noise - like a mosquito hum, and use the machine in NORMAL mode.

I use “Normal” mode, because it is easier for me to hear these positive and negative breaks in the threshold — that does not hold true for everyone. It takes time on the headphones to learn to recognize whisper signals, usually over 100-hours. Sometimes actually speeding up your swing back and forth helps to recognize these signals. The general rule however is always to SLOW down and pay attention.

Slight “Positive” signals are also called “whisper” signals. This is a very soft or slight, almost unnoticeable, rise in the threshold signal. It will always be repeatable over the target — not random. “Negative breaks,” are also referred to as whisper signals. This is when the threshold gets quieter, or goes away completely over the target. Again, negative breaks are always repeatable over a real target — not random. As you remove a little sand from over the target and re-sweep with your coil, the signal becomes a slight or stronger positive signal.

If your threshold is set too high or too low, you can miss slight breaks easily. If your threshold is not smooth enough you can miss these whisper signals easily. If you want to make your machine more sensitive and cut down on interference, make sure you are not wrapping your coil wire close to the coil down on the lower plastic rod (see photo). There can be a couple of reasons, including EMI, for an unstable threshold. The most common is too much pulse width. Sometimes you can max it out, sometimes you can only run it at the 12-1 o’clock position. It depends on the beach. Minerals in the sand and salt water can also cause the threshold to raise and lower.

I’m right-handed, so I swing the Sand Shark with my left arm. I mount the box up high and use the arm strap so that I let go of the detector and use my left hand to remove the target from the scoop. The arm strap keeps the detector right there attached to me, but gives me the ability to use both hands. Lastly, using your scoop effectively takes practice in the water. I put my toe just in back of the pinpointed target then place my scoop right in front of my toe for the recovery. This works well with practice. You’ll learn to time the waves.

DO NOT just walk up or down the beach in one direction or the other! Pick yourself a 50-yard long beachfront, and start gridding it. You start at the wet sand high mark and detect right into the water thigh-deep, move over a step and detect right back up to the high wet sand mark until the whole 50-yards or 5-hours is done. Hope this helps and feel free to PM me with any other questions or explanations.
 

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Sandman

Gold Member
Aug 6, 2005
13,398
3,992
In Michigan now.
Detector(s) used
Excal 1000, Excal II, Sovereign GT, CZ-20, Tiger Shark, Tejon, GTI 1500, Surfmaster Pulse, CZ6a, DFX, AT PRO, Fisher 1235, Surf PI Pro, 1280-X, many more because I enjoy learning them. New Garrett Ca
Primary Interest:
All Treasure Hunting
Listen to Terry, he's always right.:thumbsup:
 

OP
OP
K

KRILL

Greenie
Aug 6, 2014
17
4
TEXAS
Detector(s) used
AT PRO
Primary Interest:
Metal Detecting
Thanks for the reply. I tried the pulse several times at the 12 and also the 2 to 3 range and it didn't seem to help. I will try to get to another beach next weekend and see how it goes. There is some black sand in that beach. Could that be the problem causing the surge in the threshold?
 

Golden oaks

Full Member
Aug 4, 2012
146
112
BEACH BETTER HAVE MY MONEY!
Detector(s) used
Minelab CTX-3030
Minelab Equinox 800
Minelab Excalibur II
Tesoro Sand Shark
Primary Interest:
Beach & Shallow Water Hunting
My shark seems to raise the tone when I swing away from my body just before swinging back. It isn't too noticeable and I have come to recognize when the coil is over a target just at arms reach. I make certain the control box does not move, on the shaft, as I have had tone problems from the box's slight wobble. Experience will help & I think the unit itself is a bit chatty, but it sure is great to take in the water!

H.H. & Happy trails!
 

Last edited:

Terry Soloman

Gold Member
May 28, 2010
19,410
30,023
White Plains, New York
🥇 Banner finds
1
🏆 Honorable Mentions:
1
Detector(s) used
Nokta Makro Legend// Pulsedive// Minelab GPZ 7000// Vanquish 540// Minelab Pro Find 35// Dune Kraken Sandscoop// Grave Digger Tools Tombstone shovel & Sidekick digger// Bunk's Hermit Pick
Primary Interest:
Metal Detecting
Thanks for the reply. I tried the pulse several times at the 12 and also the 2 to 3 range and it didn't seem to help. I will try to get to another beach next weekend and see how it goes. There is some black sand in that beach. Could that be the problem causing the surge in the threshold?

Yes, the black sand in an indication that high mineralization is present on the beach but this should not cause falsing. The rise or fall of the threshold can be affected, but a good threshold can be wavy. The key to using an audible threshold is learning to recognize the "breaks" in the threshold, not the up and down "waves." This is yet another reason I advise new owners to master Normal mode before switching to VCO.
 

algeus

Jr. Member
Aug 13, 2014
86
27
Primary Interest:
All Treasure Hunting
I had this issue once at the end of my hunt, and after playing with the configuration a bit I've started thinking I will need to repair the detector. Then I simply switched it OFF and ON ,and automagically got a stable threshold again. Go figure...
 

OP
OP
K

KRILL

Greenie
Aug 6, 2014
17
4
TEXAS
Detector(s) used
AT PRO
Primary Interest:
Metal Detecting
I went to a different beach this past weekend and didn't have any problem with it surging. I tried adjusting everything and could not get it to surge there. must be something at the first beach. I found 2 junk rings a dozen or so coins and a sheetload of bobbie pins.
 

Golden oaks

Full Member
Aug 4, 2012
146
112
BEACH BETTER HAVE MY MONEY!
Detector(s) used
Minelab CTX-3030
Minelab Equinox 800
Minelab Excalibur II
Tesoro Sand Shark
Primary Interest:
Beach & Shallow Water Hunting
Bobbie pins.... I call them Roadrunners because they Beep-Beep!!!
 

Fletch88

Silver Member
Mar 7, 2013
4,841
2,367
Valdosta, GA
Detector(s) used
Garrett ATPro- 8.5x11, 5x8, CORS Fotune 5.5x9.5
Tesoro Silver microMax- 8 donut, 8x11 RSD, 3x18 Cleansweep
Minelab Excalibur ll- 10" Tornado
Minelab CTX 3030
Minelab Xterra 305
Primary Interest:
All Treasure Hunting
Krill, try sweeping from several directions, usually the bobby pins will give a drawn out sound or double beep. Most coins and rings will have a round, tight sound.
 

Terry Soloman

Gold Member
May 28, 2010
19,410
30,023
White Plains, New York
🥇 Banner finds
1
🏆 Honorable Mentions:
1
Detector(s) used
Nokta Makro Legend// Pulsedive// Minelab GPZ 7000// Vanquish 540// Minelab Pro Find 35// Dune Kraken Sandscoop// Grave Digger Tools Tombstone shovel & Sidekick digger// Bunk's Hermit Pick
Primary Interest:
Metal Detecting
Remember, broken silver and gold rings and earrings also double beep, but usually the signal is a quieter one than a bobby pin
 

Fletch88

Silver Member
Mar 7, 2013
4,841
2,367
Valdosta, GA
Detector(s) used
Garrett ATPro- 8.5x11, 5x8, CORS Fotune 5.5x9.5
Tesoro Silver microMax- 8 donut, 8x11 RSD, 3x18 Cleansweep
Minelab Excalibur ll- 10" Tornado
Minelab CTX 3030
Minelab Xterra 305
Primary Interest:
All Treasure Hunting
Very true! The long drawn out "bobby pin" I left behind could be that Rolex watch.
 

Crispin

Silver Member
Jun 26, 2012
3,584
2,856
Central Florida
Detector(s) used
Coinmaster Pro, Sand Shark
Primary Interest:
Other
To avoid deep aluminum cans sweep from several directions. If you get a strong signal in a range around the target it is probably a very large piece of aluminum or iron. I usually give these a couple of scoops worth of dig and if no change in single then I give up. Don't want to miss a huge piece of silver, but can't dig every last can either. My hunting buddy calls this "predigging holes." He comes behind me and finishes off the job. So far all my give ups have been large pieces of aluminum. Either that, or he found some massive gold or silver and didn't have the heart to tell me.
 

OP
OP
K

KRILL

Greenie
Aug 6, 2014
17
4
TEXAS
Detector(s) used
AT PRO
Primary Interest:
Metal Detecting
I only heard the double beep on a couple of bobbie pins but I didn't try sweeping from all directions. But also heard a double beep on 3 coins in one hole.
 

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