Vallon VMH3CS Mine Detector

[Ferric Toes]

Ever since than i am asking my self; is there any special reason to put electronics in sealed screened box?
Ok, one of the reasons may be "military" standard... or whatever.
But what if there is another more important reason?

The most likely reason for putting the electronics in a screened box is to thwart emi, both from the unit and coming from outside the unit. Military electronics has to be as immune as possible to outside sources of interference and not to emit spurious interference of its own making. A secondary benefit, in the case of the Vallon, is to make it difficult for prying eyes to unravel their technology by cementing the boards to the inside of the box. Maybe that is being cynical, and the real reason is to stop things shifting when being thrown into a truck and bounced across rocky and hostile terrain.

[6666]

Hi Eric just talked with our son in the army, he is a bit distracted right now he is getting bombs dropped on the camp by the bad guys, but he thinks he may have used a Vallon, but will get back in a few days when the locals settle down and he has time to talk.

[Geo]

Lets wait.....

[ivconic]

Hahaha....
Carl knows how to calm the spirits

Next thing i expect here to see is Carl to find some (so far unpredicted) reason not to open his unit! (Murphy's law: El Paso moved to unknown location...etc..)
Spirits are calm Geo.
But there is no point in continue with making wild assumptions on how things are done or not done.
I highly suspect that coil damping in Vallon is playing crucial role in fact that coil is 1.5mH and yet capable for sensing smaller targets.
But that also may be my wild assumption too.
How can we be sure? Is there any method to distinguish about coil damping relying only on measurements performed via coil connector?
And what is its front end look a like?
Few important and interesting questions may be answered ONLY if unit was opened. I can't think on different solution.
But we will have to wait and see.

[Geo]

Hahaha....
Carl knows how to calm the spirits

[ivconic]

In my reply of yesterday I stated "The electronics is in a sealed screened box and could not be removed without damage". If I cannot remove the boards from the screened box then how can I take "macro shots from pcb". I could cut or machine away the box from the boards but then I risk damage to the board and destroying the outer screening of a module that I cannot replace. A working module that is, not a faulty one. Vallon would be most unlikely to sell me one, and if they did they would expect a 'military' price. It's just a no brainer to leave it alone and put the machine back together. That way I still have something of value that I paid £*** for.

Thanks Eric. I understand You.
I guess we will have to wait.
Hopefully Carl will manage to open his unit, especially if that unit is faulty and abandoned.
I haven't missed your statement about that, i remember that you mentioned it earlier.
Ever since than i am asking my self; is there any special reason to put electronics in sealed screened box?
Ok, one of the reasons may be "military" standard... or whatever.
But what if there is another more important reason?

[Ferric Toes]

What i would like to see is its analogue part (if any). Its front end design. Its damping method. Etc...
As Qiaozhi asked; i would like to see how 1.5mH coil is damped... for example. Macro shots from pcb will disclose some of the doubts, almost certainly.

In my reply of yesterday I stated "The electronics is in a sealed screened box and could not be removed without damage". If I cannot remove the boards from the screened box then how can I take "macro shots from pcb". I could cut or machine away the box from the boards but then I risk damage to the board and destroying the outer screening of a module that I cannot replace. A working module that is, not a faulty one. Vallon would be most unlikely to sell me one, and if they did they would expect a 'military' price. It's just a no brainer to leave it alone and put the machine back together. That way I still have something of value that I paid £*** for.

[KingJL]

I found pages 10----15, 20, 27-----33, 102-104 of this report interesting. The Vallon VMH3 in this 2006 report is a much earlier model than Eric’s 2011 model.
Have a good day,
Chet


Systematic Test & Evaluation of Metal Detectors (STEMD) Interim Report Laboratory Tests Italy Technical Report · January 2006


https://www.researchgate.net/profile...ad?version=vtp

Table 2, pg. 20 indicates that the VMH3CS and the VMH3 have more differences than just changeable coils... look at the optimum speed and loss at hi and lo speeds.

[Chet]

I found pages 10----15, 20, 27-----33, 102-104 of this report interesting. The Vallon VMH3 in this 2006 report is a much earlier model than Eric’s 2011 model.
Have a good day,
Chet


Systematic Test & Evaluation of Metal Detectors (STEMD) Interim Report Laboratory Tests Italy Technical Report · January 2006

https://www.researchgate.net/profile/Adam_Lewis6/publication/268371731_Systematic_Test_Evaluation_of_Metal_Detectors_STEMD_Interim_Report_Laboratory_Tests_Italy/links/546f5dee0cf24af340c087ee.pdf/download?version=vtp

[daverave]

i think sometimes we expect too much from this site...we must respect people if they do not want to open up their machine for whatever reason...when people are ready to share then maybe they will show us inside one of these vallon machines...we must sometimes be patient.

[ivconic]

If you want to see the inside of vallon so much its best to buy your own unit from somewhere like ebay and you could do your own tests...thats what i would do if i wanted to see the inside of one and see how it ticks.

If that is the only way; than there is not even a slightest excuse for this forum to exist any more.
If all of us are pushed to buy all the models we are interested in; than what's the point of Geotech forum?
Each one of us can buy desired models and investigate them in own privacy. No share, no exchange of experiences, no correspondence...
And all the stories here so far are completely pointless.
In that course all the similar stories here on forum should be rolled back and deleted... why?
Simple answer; if you want to know details and investigate: buy it on your own!
Anyway thank you for such ingenious idea; i would never dig that out!

[daverave]

If you want to see the inside of vallon so much its best to buy your own unit from somewhere like ebay and you could do your own tests...thats what i would do if i wanted to see the inside of one and see how it ticks.

[ivconic]

The primary purpose of this thread was to investigate the possibility that the Vallon pulse induction mine detector could, in its retirement from military service, be an effective hobby detector for land and beach use. After all, even 10 years after it was introduced, it has some advanced features, a major one being effective ground balance. Being designed for military use in hostile environments, it is incredibly rugged, weather proof, dustproof and submersible to the top of the bottom shaft. Sensibly looked after it should last another 10 years in civilian use.

Having been involved in some magnetic soil studies and attended a conference in 2008 on detecting mines in difficult soils, I have read many of the reports on the use of various mine detectors in places such as Bosnia, Croatia, Iraq, and Cambodia. The Vallon was always very highly regarded for its performance.

Two years ago I purchased six VMH3CS search heads and shafts which has been thrown out as unfit for further service. 5 of the search heads turned out to be perfectly OK and one was cracked. It was the cracked one that I salvaged the swivel from, and is now mounted on the 11in search head recently built. Out of the shafts, by mixing and matching parts, I have 3 complete ones with internal cable and plugs. What I was never able to get until recently was the main control box of the VMH3CS.
Having being absent from the Geotech Forum for a few years I figured that someone might have tested a Vallon with coin, ring, nugget hunting, in mind; hence my initial post to see what the response would be.

These detectors will be coming onto the market in dribs and drabs due to upgrading of mine detection technology and downsizing of military forces and maybe they have a second life rather than being consigned to the dustbin. That is what I am investigating at present. The technical side as to how they work as well as they do is also interesting, but my facilities and expertise is limited when it come to programmed DSP. Someone else can investigate that if they wish.

From today's beach tests I am convinced that the VMH3CS is a good contender amongst other top PI units, inspite of the beach and weather conditions not being the best. I found two £1 coins which paid for two hours at the car park, plus fishing weights and other bits of metal. We did some depth tests in wet sand of US and UK coins but that is for another post.

All the correct points, all attracting huge attention here. Also you did enough from the method you chosen; measurements&tests available through coil connector. You already proved it is competitive and interesting.
And that's about all what you could do. Now is time to open it and analyze everything inside what could be analyzed. DSP certainly not, neither one of us is capable enough to dig out what's in a "black box". And that was not my point.
What i would like to see is its analogue part (if any). Its front end design. Its damping method. Etc...
As Qiaozhi asked; i would like to see how 1.5mH coil is damped... for example. Macro shots from pcb will disclose some of the doubts, almost certainly.

[ivconic]

When I get back to El Paso I'll try to pop open the Vallon and post a few pics.

[Carl-NC]

When I get back to El Paso I'll try to pop open the Vallon and post a few pics.