Need A New Pi For Beach Detecting

[BigSkyGuy]

On 12/29/2023 at 9:58 AM, Hard Prospector said:

OK guys, I've just ordered TWO new Sea Hunter MK2 detectors.  One I will have fitted out with the 10 x 14 coil and the other with  standard 8" loop.  Merry Christmas to me!

Thanks to all of you for the helpful suggestions,  I really appreciate your input

Robert

I think you will like the SH. Although it is not a ground balancing PI it handles black sand much better than a VLF. When passing over a patch of black sand you get a broad increase in threshold, but nothing that you would mistake for an actual signal. The box is quite heavy, but I hipmount mine and that works well. I never turn up the iron eliminator (pulse delay) and just dig everything. You may get a bit better depth than from your Sand Shark, especially with the big coil. I also broke the headphone jack. Garret was kind enough to replace it free of charge despite the warranty running out two weeks before. Thank you Garrett!

Happy Hunting!

[Tony]

8 hours ago, Hard Prospector said:

Easier to just grab a different detector than switch out coils (as we all know).  Plus the discussion on waterproof beach PI detectors possibly becoming extinct some day kinda spooked me.  Always wished I'd bought a second Sand Shark when I had the chance. Really appreciate all your help Tony,  perhaps when the detector arrives you'll give me some suggestions on settings,  thanks a bunch..........Robert

Sea Hunter MK2 is about as simple to use as anything out there. These are my observations

• Switch on to first position (Standard)
• Threshold to suit
• Elimination to Zero (can advance clockwise a fraction to reduce the salt audio rise from waves and swell). Leave at zero for hunting anywhere else. Elimination at zero equates to around the 15uS mark. In the surf, I ran mine at "2" or "3". This puts the delay around the 20uS mark (much like the Sand Shark)
• The wobbly shaft might be a problem. I replaced with a carbon fibre upper shaft
• Take care when aligning the headphone and coil pins into the housing
• Shallow and big targets are quite loud in the headphones. Wearing a flap hat or some small foam in the earcups helps.
• A very light application of silicone grease on the battery compartment O ring is important. Because the battery cap screws / rotates against the O ring, some grease prevents the O ring from potentially distorting. A dry O ring can "grab" against the cap. Don't screw past the indicator mark on the housing.
• The coils are great but I found the epoxy was somewhat brittle and chipped in rocky areas. I applied Plasti-Dip to mine and it solved the problem
• I ordered a spare battery cap and got some spare battery holders.

That's about it really........I might have to get another one someday. They are a no frills workhorse detector.

[Hard Prospector]

1 hour ago, Tony said:

Sea Hunter MK2 is about as simple to use as anything out there. These are my observations

• Switch on to first position (Standard)
• Threshold to suit
• Elimination to Zero (can advance clockwise a fraction to reduce the salt audio rise from waves and swell). Leave at zero for hunting anywhere else. Elimination at zero equates to around the 15uS mark. In the surf, I ran mine at "2" or "3". This puts the delay around the 20uS mark (much like the Sand Shark)
• The wobbly shaft might be a problem. I replaced with a carbon fibre upper shaft
• Take care when aligning the headphone and coil pins into the housing
• Shallow and big targets are quite loud in the headphones. Wearing a flap hat or some small foam in the earcups helps.
• A very light application of silicone grease on the battery compartment O ring is important. Because the battery cap screws / rotates against the O ring, some grease prevents the O ring from potentially distorting. A dry O ring can "grab" against the cap. Don't screw past the indicator mark on the housing.
• The coils are great but I found the epoxy was somewhat brittle and chipped in rocky areas. I applied Plasti-Dip to mine and it solved the problem
• I ordered a spare battery cap and got some spare battery holders.

That's about it really........I might have to get another one someday. They are a no frills workhorse detector.

Great stuff Tony

Thanks again!

[schoolofhardNox]

5 hours ago, bklein said:

Just got depressed using my Manticore in black sand at Newport Beach. Put a nickel on top of the sand and detect it probably >15”, depress an area 1-2” down from surface and it only sounds if the coil is an inch or so from it. I tried all modes. Sorry I didn’t have my AQ to see how it would perform.

 

That's why my Manticore sits in the corner now. That is the main reason I use a PI on beaches almost exclusively.  I think when I posted that I had issues at a beach and finally brought out the PI, some people probably thought  "user error" ☹️ I think the OP will be happy with the PI they choose over any VLF/MF if they are on those kinds of beaches. Thanks for that video. It clearly explains the difficulties of MF. The Garrett Carrot did a better job of finding that nickel  🤣

[Tony]

9 hours ago, bklein said:

Just got depressed using my Manticore in black sand at Newport Beach. Put a nickel on top of the sand and detect it probably >15”, depress an area 1-2” down from surface and it only sounds if the coil is an inch or so from it. I tried all modes. Sorry I didn’t have my AQ to see how it would perform.

 

Can I ask what your Sensitivity setting was in this location?

The detector is extremely chatty from about 40 seconds on with it laying on the ground.....even before the pinpointer is turned on around the 1:00 mark.

Thanks.

[bklein]

I’m sorry I’m not sure of the settings in the video. I usually ran deep or LC mode and prospecting audio but during my time testing seen for the video not sure.  If all metal the sensitivity was likely like 23. But towards the end I thought I’d see what would result if I ran in discriminate with Sensitivity cranked to 31.  I was thinking if
the detector has any ability to pick out a non-ferrous target (the nickel) from the black sand I’d be masking the iron and be more sensitive to everything else. That resulted in short random tones that you hear.  Not enough of them to overload my brain.

I went back and got a bucket of sand yesterday with my wife’s complete disapproval. She was pissed - wanted us to walk our dogs.  This next day I was at an area a few blocks north and the sand was different - not as many black sand concentrations. 
My friend also went back yesterday and found more targets than the day before, perhaps because the black sand wasn’t as concentrated.

One of these days I’ll get around to making a dual mic setup so I can narrate while the detector audio can be heard as well. 
 

I had seen a video by Fun With Jim showing the masking (Equinox 800) of coins by the dry black sands at Sunset beach, perhaps 5 miles north. He seems to get good targets there regardless. 
 

My goal is to eventually get a home test platform in a concrete mixing pan so I can test several detectors.

[cjc]

I would also add that it's not just fast salt  and black sand that cripple VLFs.  Its the interference  created  by inclines, hills, seabed contours, weed beds, different types  of material under the coil--any number of  things.  There's just no contest.  I too  have engaged  in  this same wishful  "VLFs have gotten so  powerful" type thinking but found it to be not true.  At the same time there's such a thing as benign  conditons--or places  where trash  targets and the  general  depth  of what there is to be found make VLF the  way  to go.  cjc

[EL NINO77]

9 hours ago, bklein said:

I’m sorry I’m not sure of the settings in the video. I usually ran deep or LC mode and prospecting audio but during my time testing seen for the video not sure.  If all metal the sensitivity was likely like 23. But towards the end I thought I’d see what would result if I ran in discriminate with Sensitivity cranked to 31.  I was thinking if
the detector has any ability to pick out a non-ferrous target (the nickel) from the black sand I’d be masking the iron and be more sensitive to everything else. That resulted in short random tones that you hear.  Not enough of them to overload my brain.

I went back and got a bucket of sand yesterday with my wife’s complete disapproval. She was pissed - wanted us to walk our dogs.  This next day I was at an area a few blocks north and the sand was different - not as many black sand concentrations. 
My friend also went back yesterday and found more targets than the day before, perhaps because the black sand wasn’t as concentrated.

One of these days I’ll get around to making a dual mic setup so I can narrate while the detector audio can be heard as well. 
 

I had seen a video by Fun With Jim showing the masking (Equinox 800) of coins by the dry black sands at Sunset beach, perhaps 5 miles north. He seems to get good targets there regardless. 
 

My goal is to eventually get a home test platform in a concrete mixing pan so I can test several detectors.

It shows a high concentration of magnetite in the sand...but not so high that it overloads the detector...,, maybe somewhere around 20% of the magnetite content in the sand......
How did you set the recvery speed  on the Manticore?..

In any case... here you can see that the discrimination work of the VLF detector on such strong mineralization is no longer effective..but one of the possibilities is to use open discrimination and use it in a similar style as an all metal detector,,,

[bklein]

Not sure what you mean by iron reactivity settings - but the iron settings were default and no added discrimination masking. 
Yeah, funny that the Carrot found the nickel just fine. But is the Carrot a PI design?

What do you think of my experiment running in discriminate with higher sensitivity? The nickel is not giving me an iron signature - it’s not seen at all (unless within an inch of the coil). If I was an engineer at Minelab this would be a challenge I’d love to take on.  Must be a way for MC coil and electronics to function better in this concentration sand?

 

[schoolofhardNox]

3 hours ago, bklein said:

Not sure what you mean by iron reactivity settings - but the iron settings were default and no added discrimination masking. 
Yeah, funny that the Carrot found the nickel just fine. But is the Carrot a PI design?

What do you think of my experiment running in discriminate with higher sensitivity? The nickel is not giving me an iron signature - it’s not seen at all (unless within an inch of the coil). If I was an engineer at Minelab this would be a challenge I’d love to take on.  Must be a way for MC coil and electronics to function better in this concentration sand?

 

Here is a bit about the Garrett pinpointer from their online manual. It operates at 11.5 kHz.

international standards:
• FCC • CE • RoHS • ICNIRP • IEC 529-IP 68
SPECIFICATIONSModel Name: Garrett Pro-Pointer® AT
Model Number: 1140900
Operating Temperatures: -35ºF (-37ºC) to 158ºF (70ºC)
Operating Frequency: 11.5 kHz
Waterproof Rating: 20 foot (6 meter) maximum depth; IP 68
Tuning: Automatic or manual retune
Indicators: Proportional audio/vibration pulse rate
Controls: Power, Retune, Adjust switch
Dimensions: Length: 9” (22.9 cm)
Thickness: 1.5” (3.8 cm) tapered to
.875” (2.2 cm)
Weight: 6.5 oz. (0.2 kg.), with battery in
Battery: Single 9V (included)
Battery Life: Carbon: 16 hours
Alkaline: 30 hours
Rechargeable: 8 hours
Warranty: 2 Years, Limited Parts/Labor
Patent Information: US 7,575,065; D583,261 and
patents pending