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Question for Eric Foster
Posted by: landman
Date: April 15, 2017 07:36AM
Eric, can the Aquascan Aquapulse AQ1B ever be modified to
have a discrimination circuit on it?
Reason I even ask is because one of the techs at Kellyco suggested
if and when it is done it would be by far the best water

3 foot probe
DRS Ground Exper Pro

Re: Question for Eric Foster
Posted by: Eric Foster
Date: April 15, 2017 02:54PM
I presume that you are looking for ferrous/non-ferrous discrimination? This is something that is long overdue in a pulse induction detector and several ideas are being progressed at the moment.

When this was tried before in a detector that Mel Fisher used, the sea water background signal made the discrimination unreliable. Technology has moved on a lot since then and it is worth having more tests done.


Re: Question for Eric Foster
Posted by: BenjaminE
Date: July 12, 2017 11:01AM
To Eric Foster,

I have used the Whites Surfmaster Dual Field PI for just under two years. And, I have found hundreds of rings with it.

Unfortunately, what I have discovered is that I do not believe I can pick up a gold ring past 16 inches. I run at full 100% gain. The sensitivity knob is just turned on just a hair. And, the threshold is barely audible.

I have no complaints about all of the gold that I have found. Only, I would like to be able to detect roughly three to four inches deeper. In some areas, the bedrock is around 18-20 inches deep. And, I cannot pick up small targets, like rings, in those areas. I know they are there. I simply cannot get a signal.

If Whites does not come out with a submersible detector that goes deeper, could you recommend a simple submersible PI unit comparable to the Dual Field, that will pick up rings at 18-20 inches?

I am uploading my most recent batch of 37 gold rings, to give you an idea of what I find. There are some areas where I know that I would do really well, if only my detector could go just a few inches deeper.

Any thoughts or suggestions would be greatly appreciated. Since I own three Dual Fields, I would even be willing to pay to have one modified to go deeper, if that is possible.

By the way, I don't need a loud target signal. Even a subtle signal would be enough. I have dug many deep rings off of a very subtle signal, that easily could have been missed. Unfortunately, it seems that past 14-16 inches, there is no signal at all...



Re: Question for Eric Foster
Posted by: Eric Foster
Date: July 17, 2017 07:52AM
Hi Ben,

You have certainly done very well with the Surfmaster and can understand the desire to go deeper. What size coil do you have with the Surfmaster? One of the greatest gains to be had is simply by increasing the coil diameter from say 10 inches to, say, 15 inches. The trade off is that pinpointing is less accurate, water signal is increased,and emi noise pickup is greater. Physically sweeping a large coil from side to side in water is also more tiring. However, a 15in coil is perfectly good for most of the objects you are hunting for.

Before going further into electronic improvements that are possible in addition to a larger coil, what is the greatest depth of water in which you search? i.e. waist deep, chest deep, snorkel or scuba.


Re: Question for Eric Foster
Posted by: BenjaminE
Date: July 22, 2017 10:57AM
Mr Foster, thank you so much for taking my question.

I have the Surfmaster Dual Field PI, with the large yellow coil. I do not believe that there is a larger coil.

I snorkel - no scuba. Generally, I work in water up to around seven or eight feet deep, and all the way back to the shore. I have an extension on the detector, so with my long arms I can snorkel and reach down to the bottom. Also, I dive to the bottom, and dig everything up by hand. Rocks and small boulders are no obstacle. I use a garden trowel, and no longer use a scoop.

I hunt in the Mexican Caribbean. The sand is composed of pulverised coral. The ground does not appear to be mineralized with iron. I run the Dual Field at maximum gain, with sensitivity close to maximum. If there are many waves, and the detector is more prone to falsing, I adjust the sensitivity to make it quieter. If the water is lake-like, I use greater sensitivity. I run full gain all the time.

In a number of instances, I have recovered lead cloth bale seals at around 16-20 inches. These seals weigh between 30 and 35 grams. I can detect them deeper than rings, I assume due to weight and density.

Also, I can detect old Spanish musketballs at probably around 15 inches. They weigh about 20 grams each.

Here is a recent pile of gold and platinum rings, now at about 213 grams. As you can see, most all of the rings are wedding bands. I can pick up large gold rings at around 16 inches. But, the thinner gold rings, maybe 2-4grams, are coming in at maybe eight inches to a foot, tops. And, the limit is when the signal is faint, and "iffy". Whenever the signal is faint, I pretty much always dig!

What you will notice is that I have never found a thin delicate ring with a large precious stone on it. Even out of a hundred gold rings, none are thin and delicate, with large stones. My theory, for whatever it is worth, is that thinner high dollar rings, with big stones, are harder to detect than the heavier 18k bands, which are more massive. I say this because the thinner gold rings in general are hard to pick up if they are beyond eight inches. So, this is another reason why I am interested in a more powerful detector comparable to the Surfmaster. I would like to be able to hit a heavy 18k ring at close to 20 inches, while getting more depth on the thinner rings, if this is possible.

My sense of depth is based on the length of my forearm. From fingertip to elbow my forearm is a lanky 19 inches. And, the distance from my fingertips to the middle of my forearm is about 12 inches.

So, once the objects pop out of the bottom of deeper holes, I put my arm in to try to get an idea as to the depth of the hole, based on the distance my arm goes into the hole. I do this on notably deep objects. If it takes over twenty minutes to dig a signal, I usually take a break, and look for some shallow stuff to dig, and then return to finish digging out the object. In some cases, after a good twenty minutes of digging, I have unearthed fairly large rings, that were deep, and under rocks. But, I don't think that I have found a ring beyond 16 inches, whereas the lead cloth seals come in deeper, and can take even longer to dig out.

It would seem to me that after thousands of hours of using the Surfmaster D.F, I am becoming familiar with its limits. In areas that are sanded in elbow deep at about twenty inches I can dig to the bottom by hand, but I cannot get a signal on anything, unless it is the size of a pocketknife, or larger. Nothing smaller comes in. No rings, no coins, nada. Yet, such areas are heavily frequented by snorkelers and swimmers. So, there are probably thousands of small objects just out of reach that could be dug by hand. But, currently I either have to wait for a hurricane, or find a better detector that runs a few inches deeper.

From the little I have gathered, I suspect that maybe you developed a deeper running PI? Would the Aquastar do the job for me? Could I hit a coin, or a ring, with the Aquastar at around 20 inches??? Unlike other detectorists, I reject the notion that the Surfmaster goes too deep. And, I reject that idea that digging fishing weights is somehow "unwanted". Fishing weights oftentimes are found in the same range as heavy gold. But, in some cases, these objects could be just a few inches out of range of the Surfmaster.

Any help would be immensely appreciated. The main thing that I am looking for is a few more inches. If I could hit a heavy ring at 20 inches, it would be ideal.



Re: Question for Eric Foster
Posted by: stephenscool
Date: July 30, 2017 08:29AM
Are you picking up thin bands at depth or just big 18k at depth? If you are hunting in deep water the salt water gives off more of a signal making those thin little bands harder to hear through the noise. Try adding some delay and turning up the volume inside the box... and listen for deep whispers, even weak signals if you are in deep waters

Re: Question for Eric Foster
Posted by: lytle78
Date: July 30, 2017 10:20AM

I don't know if youmjave seen any of the other posts I have put up with this video link - if so - disregard. If not, have a look. This detector has iron discrimination to it's full detection depth. Fisher has recently hired the designer of this prototype - the Manta - a french guy named Alexandre Tartar. Theynhave announced that they will develop production Pulse Induction detectors based on this platform. Hopefylly before I'm too old to detect! Check out the good signal they get in the last part of the first video of the large ring at 16". In the 2nd video, they get 50cm on the same ring with the Manta - that's a hair less than 20"

Rick Kempf

Re: Question for Eric Foster
Posted by: stephenscool
Date: July 31, 2017 12:46AM
Couple other things forgot to mention that you can try. Crank the gain, increase delay, turn up volume in the box, lower threshold to barely audible or inaudible. Dig anything you hear.

2nd.. Crank volume, lower gain slightly (play with it), keep threshold the same. Ignore all loud obvious junk signals, only dig the ones barely heard... there are lots of settings to play with.

The volume control in the box can basically be used as a discriminator (hello fisher). Ignore loud surface signals. Then if you can shape and size the target on top of that you are in business

Edited 1 time(s). Last edit at 07/31/2017 12:49AM by stephenscool.

Re: Question for Eric Foster
Posted by: daverave
Date: September 05, 2017 05:04PM
you say about the manta doing 20" on a 18ct gold ring but even some home made detectors can do that...a detector i made several years old can do 20" on a 9ct heavy gold ring and about 18" on a platinum approx 7g wedding band ring...i think this french guy may have got some of his early idea's from eric foster's machines.

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