Jump to content
Sign in to follow this  
Mike Hillis

My Requirements For A Micro / Tiny / Small Jewelry Detector

Recommended Posts

Hunting tiny gold jewelry in inland sites is just so different from mainstream detecting methods that unless you do it you don't understand the requirements.    

#1.   EMI stability.   Your detector has to be stone cold stable.  No spurious noise.  None.  The signals you are after are small tight signals and you can’t hear them if your detector is making spurious noises.

#2.   The detector needs to be able to keep its HOTs at low gain/sensitivity settings because:

a... You need to be able to focus on the right depth of signals and those tiny signals are not deep.  Most of the time they are just down in the grass roots.   You want to focus only on the top three to four inches of depth.   If you have to run your sensitivity at or near max all you are doing is masking the desired signal response with reports from all the other signals surrounding it and below it.  And in cases where the ground minerals are high, the ground itself will mask the response.  

b... You need to control the coil foot print.  In this type of hunting you don’t want coil edge surface responses.  You only want to hear what is directly under your coil.   Concentric coils work better at this than DD coils.  DD coils are ok but you get better footprints with concentric and tighter readings on your meter.

#3.  The higher the operating frequency, the more important the above become.  As the operating frequency goes up, the level of discrimination goes down because the trash targets hit harder and sound better.   In other words, the higher the operating frequency the better the trash sounds and responds.

#4.  Notch discrimination or some other form of discrimination that will allow you to focus just on the signal range you are hunting.   The only range of signals you are interested in are in the ferrous/non-ferrous boundary range and the foil range up to maybe the nickel reading.   All other signals are distractions.

I'm editing to add a number #5.   Tiny signal audio boost is a big plus if it can be deployed while keeping original signal response integrity.  

I'll close with this.....You can take a gold prospecting unit onto a woodchip playground or a sand pit and as long as it can handle the EMI you can hunt with it on normal settings.  But if you are targeting sites  where good quality, tiny jewelry is most likely to be present, you will be working a lot of turf sites where a prospecting detector's normal feature set isn't going to be very helpful. 



  • Like 6

Share this post

Link to post
Share on other sites

Great concrete advice - based on experience.  I know you aren’t into PI’s, but consider this.

The Manta PI, which is now in the process of final development by Fisher might make an interesting tiny gold finder.

It has a very short minimum pulse delay - 8μ seconds or so.  that should make it able to detect all but the tiniest gold, especially at the shallow depths you are talking about.  The sensitivity is variable and it ID’s or excludes all but huge ferrous as well as high conductors. the set point for that control is variable. 

The testing up to now of this device has been pretty  Much at the beach because it is designed to be a killer on gold in salt water.  It hasn’t - as far as I know - been tested in the environemnts you are talking about.  I suspect with the correct adjustment of controls it might prove a killer in the grass and in tot lots.

Maybe Fisher should let you test it for that.

  • Like 1

Share this post

Link to post
Share on other sites

Hi Rick,

Anything can hunt a tot lot,   If you want to hunt tiny targets in a tot lot, just get a normal high frequency gold prospecting unit and have at it.  Totlots and sand lots you dig everything just because you can, its easy to dig everything.

Turf is where the restriction is at.   You can't dig everything in turf and you don't want to dig everything in turf.   It will look like the top of Hacksaw Ridge in a very short period of time if you try to dig everything in these turf spots.  

I had a Whites TDI for a season.  The two biggest drawbacks I had with the TDI was 1)  it lumped small non-ferrous and small ferrous targets together.   I couldn't tell a paper staple from an earring.   and 2) the ridiculous coil control it required to keep the ground from responding.   As long as the ground was flat and I kept the coil 3 inches or higher off the ground I had a silent detector but in uneven ground every irregularity made it report, which resulted in having to keep the coil even higher off the ground and, if I didn't keep my mind in the game, staying on top of identifying what was sounding off, the ground or a target,  I could end up chasing a ground surface irregularity like it was a target.   It did work well for high conductors, however.

So....the Manta PI would need to have small ferrous rejection, (no staple responses) with some form of ground balance to kill the surface irregularity responses, and some form of discrimination to limit what reports.    8 ns is extremely low and will be somewhat like hunting with a high frequency VLF.   Everything is going to report.   There will need to be some low conductive non-ferrous discrimination.   The only way you can do non-ferrous discrimination like this with a PI is by measuring multiple PI pulse delays:   Hits at 8 ns, still hitting at 11 ns, don't give an audio response.  Hits at 8 ns, decay is complete by 11 ns, give an audio response or a meter reading or whatever.   Last I checked they haven't started making these yet where you can dial in a bottom and a top pulse delay range.  

As of now the Whites V3/V3i is the only detector on the market today that can kind of do that by comparing the 22kHz and the 3kHz signals real time so that you can see and compare the results at the same time.   22kHz screams on everything,  the 3 kHz say mass, no mass.  Audio signal gives target size hints    However their coils aren't really built with a tight enough null so there is an inherent limitation to signal size beyond frequency limitations.  But it works.

If Fisher gets something designed that can hunt that environment I would be happy to prove it.



  • Like 1

Share this post

Link to post
Share on other sites

Good view, Mike..., at Spectra is a dimensionally good-sensitive and stable Vrated and Emi resilient coil - it is the foundation for this detector ... For example 6x4 shooter is low RX gain is1050266751_iphoneMarec52018013_DxO.jpg.98e7e245d11bb7b5273ab94ebacc511b.jpg low sensitive to small things ...

well there are also differences in range at different frequencies and multi 3F

iphone 5S marec 6 001_DxO.jpg

  • Like 2

Share this post

Link to post
Share on other sites

Thanks for the feedback Mike.  By the end of the year, I hope, you might get a chance to play with one!


Share this post

Link to post
Share on other sites

Thanks Rick.  Maybe so.  Maybe not.   I got a call from someone's shipping department a couple of weeks back wanting to send me something.  I was busy and focused on the task at hand only listening with half an ear and declined shipment.   I don't even know who it was that called or what company they were with.   I think I thought it was a phishing scam to get my info and in any event I was in a hurry to get off the phone and not loose my focus.  

El Nino77, that is some work you have done.  I'll have to take some time to review it closer than I have.  



Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

  • Similar Content

    • By JP.Diggzzit
      Hit this deep, 10 gram Platinum ring on the beach recently.  Initial signal was a faint, choppy tone, jumpy 12/13 ID.  After the 1st and 2nd scoops the signal went to negative #'s and gave me the iron tone.  After the 3rd scoop the signal was gone.  I utilized pinpoint mode thereafter and recovered the target after the 5th scoop.  Solid 13 out the hole.  Wet sand was hard packed so I don't believe the target was moving or sinking, no water filled the hole.  Has anyone else experienced an initial good target going to negative #'s/iron readout?  Halo effect on non-ferrous?  Positive this target was at the brink of detection range...14" - 15" inches.  Impressive depth but I will not trust that iron reading/tone if it is mixed with a positive reading/tone going forward. 
      I run Beach 2 with no discrimination almost exclusively on the beach.
      GL & HH!

    • By phrunt
      Disclaimer: I've only really been interested in Gold hunting so I'm pretty clueless in using my Nox for jewellery hunting.
      This might be a challenging one, a farmer I knows wife lost her wedding ring in a paddock and didn't realise,  Later the same day they run a plough or some sort of farming gadget over the paddock as they planted it out with grass seed so the ring is likely buried.  They're pretty certain it was lost in this paddock.
      I have been recruited to try find this ring, it's 24k gold with about 20 diamonds on it.  The guy originally gave me the wrong description of the ring, probably his ex-wife's ring he described as he said it had 1 diamond and sapphires 😄
      The paddock is really junk filled, I went and swung my detector over it yesterday morning before skiing and there was iron I assume setting the detector off everywhere in all metal mode.
      I know the VDI numbers are extremely useful for coin hunting but will they help for finding this ring, I really don't want to have to dig everything! Is there a range I should be targeting? I assume Field 1 will be the best mode or maybe Park 1 seeing there is a lot of junk?
      Small gold when prospecting always comes up under 10 on the VDI's, I am guessing a ring will come up higher? 
      Would the Equinox be my best choice or would I be better off using my T2 with Mars Tiger 10x13" or 15" round Stock T2 coil for more ground coverage? I also have a Garrett Euroace with Nel Tornado 12x13" I could use if that would be best.  That's the biggest coils I own.
      I have a GPX 4500 with a 15x12 DD Commander I could use but I don't want to dig lots of junk and I was hoping VDI's would be useful.
      I told them I'd do the hunt for nothing when they tried to pay me as it's a bit of fun for me anyway but they said they can't allow that and they'd give me a few sheep for my freezer for my efforts even if I don't find it but I'm sure if I find it they'll force me to take some sort of payment, I will try refuse as I really don't want it but it will be difficult to not take it when they're forcing it....
      The paddock is about 3 hectares!!!!!  Just over 7 acres so I really have a job ahead of me.  The soil is extremely mild but it seems to have its share of junk.  I assume rusty old nails and tractor bits and mower blades whatever else over the years.
      Any help appreciated.
    • By Jackpine
      are starting to heat up.  I spent a couple hours at the sand bar this morning and managed a couple pieces.  Nothing to brag about as the stones in the ring are CZ's.   The hoop earring is silver plated.  There were 3 other hunters out and their finds were meager as well with only one gold ring being reported at this spot so far.  
      The wire mesh I had welded in the scoop worked a dream.  The earring back in the pic is just one of many tiny bits it captured saving a lot of time. 😉
      The nut

      The heartbreak

      It really felt good to get out and get started on this years "crop"!  👍
    • By Randy Dee
      This post is mainly directed to UK field detecting where we have had social open air gatherings since Medieval times and on fields littered with coke. I used these settings yesterday and I was hopeful of finding at least one gold necklace / chain but alas none, better luck next time.
      As most of us know it is almost impossible to find a fine gold chain with any metal detector and as it is a long story why but mainly due to Eddy Currents and the metal detector rejecting coke which fits into the same frequency range as thin and fine gold and as here in the UK we find our permission fields littered with coke which mostly emanates from the days of steam engines powering farm equipment and the spreading of night soil as a crop fertilizer and which was collected from house middens and where the ashes from the household coal fires was used to cover the stinking human excrement, these ashes contained large cinders which survive for donkeys years in the soil and give off wonderful signals for metal detectors.
      This information on how to adjust the Tone Breaks to enhance the chances of finding gold chains during field detecting is only applicable to the Minelab Equinox 800 as it has the advanced settings capability.
      To alter the "Tone Breaks" it involves making changes to three "Target Tone Dependencies" which are "Number Of Target Tones", "Target Pitch" & "Target Volume".
      Here is my effort to change the settings to cover the frequency conductive range to give off a signal from thin gold chains in the discrimination zones, at present the default Discrimination zone is -9 to +2 and it is the Zero to +2 segment where gold chains show.
      So first of all select either "Field 1 or 2" your choice.
      Then go to "Target Tone" choose 5 tones.
      Then go to "Tone Breaks" and set the 5 tones as thus T1 = -9 to 0, T2 = 1 to 2, T3 = 3 to 28, T4 = 29 to 38, T5 = 39 to 40.
      Then go back to "Tone Volume" and set tone segments to T1 = 1, T2 = 15, T3 = 25, T4 = 25, T5 = 15.
      Then go to "Tone Pitch" and set the tone segments to T1 = 1, T2 = 15, T3 = 25, T4 = 20, T5 = 16.
      To move from from one tone segment to the next segment use the "Accept / Reject" button ( \//x ). These settings are working for me but then again they may not be every-bodies cup of tea.  
    • By schoolofhardNox
      Well today was beach hunt #7 with the Equinox. There wasn’t a lot of detecting room, with the way the tide was today. Also, a lot of people walking and laying out on the beach. It’s getting crowded out there. I was hoping to keep the streak alive today and I didn’t have to wait very long. First good target was the pink stone 14 K Gold ring. I almost didn’t believe it. That made the rest of the hunt less stressful and more enjoyable, as the gold streak would continue. But I didn’t expect to get too much more, but the finds kept coming.  All the time I just kept shaking my head, I can’t believe what Minelab has done!!! 4 gold rings, some silver and a small amount of clad. The broken class ring was found in 2 separate holes about 60 ft apart. The breaking points match up perfectly…they were part of the same ring. The tiny targets were out in full force, as well as the pull tabs too. A small price to pay for the good finds that can come with it. Probably the smallest chain this machine can pick up. Had a hard time locating it once it was out of the hole. I was glad to get out today… a picture-perfect weather day!

    • By Mike Hillis
      Patch Gold = A patch is a hot spot with the right ingredients (cover, clientele, and activity) to allow re-occurring jewelry losses over time.  Patch Gold is gold jewelry found in this hot spot.   
      This is nice piece of Patch Gold from one of my patches.   18k White gold with a very pretty diamond I found a few weeks back.