Vallon VMH3CS Mine Detector

[kingswood]

I dont think that ground balancing out some targets with similar properties is only a Vallon issue....My GPZ7000 will, as will my old GP3000....

[Ferric Toes]

Let us be correct - to quote correctly , without interpretations . This mine post contains information between the rows ? here's a precise quote , - 3.3.3 Important Notes , from the instruction of Vallon : http://www.vallon.de/download/Vertri..._soft_1_14.pdf
,,NOTE
The program ,,mineral'' adapts the detector to the metallic properties of the
soil. Mines containing metal components with the same electromagnetic
features may be overlooked.
Use program ,,mineral'' only if absolutely necessary. ''
Happy Holiday of All Women, Happy March 8^th . I wish health and happiness .With best wishes , to make your dreams come true . Make your thoughts come true .

If you look carefully you will see that TH'r's quote is from the 1.19 later version of the VMH3CS manual, which states 'Mode mineral adapts the detector to the magnetic properties of the soil'. Your earlier manual does say 'metallic', but this is not a correct description for the iron minerals found in soil, rock, or earthenware ceramics. Maybe the translation from German to English was the problem, but has subsequently been corrected.

Having been involved in the past with manuals for military and police equipment, the fact that it states that the mineral mode should only be used if absolutely necessary is because most operators would struggle in live field conditions to set up the GB accurately. Basically what they want is a 'switch on and go' detector with no critical adjustments. In the Afghan sand, probably all that was needed is normal mode and operators would be discouraged from using anything but this mode, which could then result in limitations on certain targets. Cambodia, Laos, and other places, have soil with magnetic properties and mines are mostly cleared by humanitarian demining operatives who are properly trained and have more time than soldiers in a war zone. Mineral mode would be essential in those areas as many of the reports indicate.

Eric.

[MTammet]

If you look carefully you will see that TH'r's quote is from the 1.19 later version of the VMH3CS manual, which states 'Mode mineral adapts the detector to the magnetic properties of the soil'. Your earlier manual does say 'metallic', but this is not a correct description for the iron minerals found in soil, rock, or earthenware ceramics. Maybe the translation from German to English was the problem, but has subsequently been corrected.

Having been involved in the past with manuals for military and police equipment, the fact that it states that the mineral mode should only be used if absolutely necessary is because most operators would struggle in live field conditions to set up the GB accurately. Basically what they want is a 'switch on and go' detector with no critical adjustments. In the Afghan sand, probably all that was needed is normal mode and operators would be discouraged from using anything but this mode, which could then result in limitations on certain targets. Cambodia, Laos, and other places, have soil with magnetic properties and mines are mostly cleared by humanitarian demining operatives who are properly trained and have more time than soldiers in a war zone. Mineral mode would be essential in those areas as many of the reports indicate.

Eric.

The only problem Vallon had in Afganistan was emi from jammers.

Best
Mihkel

[Rocketdemon]

Yes, I have had some 1st hand experience of devices used by UK Army in Afghanistan to deal with IED issues, I am not surprised that the Vallon couldn't cope with the very high RF levels!

Pete

[MTammet]

Yes, I have had some 1st hand experience of devices used by UK Army in Afghanistan to deal with IED issues, I am not surprised that the Vallon couldn't cope with the very high RF levels!

Pete

Vallon was built to deal with printed pcb boards. Take a piece of thin copper 5mm copper tape and look at the depth in normal mode. Same with bad silver mediaeval pennies 0.19+0.22 g

mihkel

Mihkel

[Ferric Toes]

Yes, good work and I enjoy reading all posts by you guys.

The curves Eric posted are expected. The three metal target look to be Exp^(-t/Tau) whereas the Ironstone looks to be -1/t.
If plotted on a Log/Lin and log/log graph this should be obvious.

Very interesting that even this Vallon detector has a GB hole.

Here is the confirmation on a log/Lin graph with the 1 Lev giving the expected exponential decay and the ironstone power law decay.

Eric.

[green]

Here is the confirmation on a log/Lin graph with the 1 Lev giving the expected exponential decay and the ironstone power law decay.

Eric.

[ATTACH]45611[/ATTACH]

I see the 1 lev has a TC about 19.5us. I have a 1963 20 centimes francaise with a TC about 17.5us that falls almost to the bottom of the hole with my detector with the time settings I used.

[Ferric Toes]

I see the 1 lev has a TC about 19.5us. I have a 1963 20 centimes francaise with a TC about 17.5us that falls almost to the bottom of the hole with my detector with the time settings I used.

I measured the TC of the 1 Lev by the method in post 223 in the 'target response tester' thread. I get 23.2uS, which is not far removed from your 19.5uS. My measuring window was between 40 and 63uS where signal/noise ratio is still very good 3.0V and 1.1V.



The detection ranges I get with the VMH3CS and stock coil are 14" (35.5cm) in Normal and 7" (17.8cm) in Mineral. Mineral being balanced on Australian ironstone. My 11.5" circular coil does better at 16" (40.6cm) and 10.5" (26.7cm). All measurements are for 2 LEDs lighting consistently. I'm not sure why the 11.5" coil does better in the Mineral mode, but it definitely seems to.

With this Vallon the coin is in the hole but not at the bottom. With a TDi detector, I once filed a piece of lead so that it was not detectable in the GB setting for ironstone. However during testing it slowly started to react, which I found was due to the slight heating caused by my fingers holding it. The hole, or notch, must be quite narrow.

Eric.

[Riss]

I measured the TC of the 1 Lev by the method in post 223 in the 'target response tester' thread. I get 23.2uS, which is not far removed from your 19.5uS. My measuring window was between 40 and 63uS where signal/noise ratio is still very good 3.0V and 1.1V.

[ATTACH]45655[/ATTACH]

The detection ranges I get with the VMH3CS and stock coil are 14" (35.5cm) in Normal and 7" (17.8cm) in Mineral. Mineral being balanced on Australian ironstone. My 11.5" circular coil does better at 16" (40.6cm) and 10.5" (26.7cm). All measurements are for 2 LEDs lighting consistently. I'm not sure why the 11.5" coil does better in the Mineral mode, but it definitely seems to.

With this Vallon the coin is in the hole but not at the bottom. With a TDi detector, I once filed a piece of lead so that it was not detectable in the GB setting for ironstone. However during testing it slowly started to react, which I found was due to the slight heating caused by my fingers holding it. The hole, or notch, must be quite narrow.

Eric.

,,slight heating caused by my fingers holding it '' - well yes ! ?Piece of lead heats up because you hold it in the iron grasp ( iron hand ) of yours ,, Ferric Toes ''

[Riss]

I measured the TC of the 1 Lev by the method in post 223 in the 'target response tester' thread. I get 23.2uS, which is not far removed from your 19.5uS. My measuring window was between 40 and 63uS where signal/noise ratio is still very good 3.0V and 1.1V.

[ATTACH]45655[/ATTACH]

The detection ranges I get with the VMH3CS and stock coil are 14" (35.5cm) in Normal and 7" (17.8cm) in Mineral. Mineral being balanced on Australian ironstone. My 11.5" circular coil does better at 16" (40.6cm) and 10.5" (26.7cm). All measurements are for 2 LEDs lighting consistently. I'm not sure why the 11.5" coil does better in the Mineral mode, but it definitely seems to.

With this Vallon the coin is in the hole but not at the bottom. With a TDi detector, I once filed a piece of lead so that it was not detectable in the GB setting for ironstone. However during testing it slowly started to react, which I found was due to the slight heating caused by my fingers holding it. The hole, or notch, must be quite narrow.

Eric.

To leave the jokes . My compliments-by raising the target temperature its conductivity decreases. This causes the decrease of the time constant of the target . And respectively to emergence from the bottom of the hole GEB .

[Ferric Toes]

To leave the jokes . My compliments-by raising the target temperature its conductivity decreases. This causes the decrease of the time constant of the target . And respectively to emergence from the bottom of the hole GEB .

You got it! It also happens with non-conductive ironstone resulting in noisier ground on a hot sunny day. Stones on the surface heat up while those underneath stay cool. This temperature difference give a small shift in decay rates between those in the sun and the shaded ones. Best times to search are at night or after a rainstorm when temperatures even out and ground noise is quieter.

Eric.

[green]

I measured the TC of the 1 Lev by the method in post 223 in the 'target response tester' thread. I get 23.2uS, which is not far removed from your 19.5uS. My measuring window was between 40 and 63uS where signal/noise ratio is still very good 3.0V and 1.1V.

[ATTACH]45655[/ATTACH]

The detection ranges I get with the VMH3CS and stock coil are 14" (35.5cm) in Normal and 7" (17.8cm) in Mineral. Mineral being balanced on Australian ironstone. My 11.5" circular coil does better at 16" (40.6cm) and 10.5" (26.7cm). All measurements are for 2 LEDs lighting consistently. I'm not sure why the 11.5" coil does better in the Mineral mode, but it definitely seems to.

With this Vallon the coin is in the hole but not at the bottom. With a TDi detector, I once filed a piece of lead so that it was not detectable in the GB setting for ironstone. However during testing it slowly started to react, which I found was due to the slight heating caused by my fingers holding it. The hole, or notch, must be quite narrow.

Eric.

I have a Excel program that simulates a PI with GEB. Charted TC vs amplitude for different TC targets. Data on left is output from simulator. Ground with a -1.07 slope was balanced by adjusting GEB sample time until integrator out with GEB on was near zero. First column is PI timing with 1000samples/second. Second column is integrator out with GEB off, third column is integrator out with GEB on(slope=-1.07). Last two columns are the target, GEB off and on. GEB off amplitude was adjusted for 1000 for each TC. GEB on is reading when GEB off is 1000. The hole is quite narrow at the bottom. Different timings and ground slope could or would effect hole shape.

[MTammet]

I have a Excel program that simulates a PI with GEB. Charted TC vs amplitude for different TC targets. Data on left is output from simulator. Ground with a -1.07 slope was balanced by adjusting GEB sample time until integrator out with GEB on was near zero. First column is PI timing with 1000samples/second. Second column is integrator out with GEB off, third column is integrator out with GEB on(slope=-1.07). Last two columns are the target, GEB off and on. GEB off amplitude was adjusted for 1000 for each TC. GEB on is reading when GEB off is 1000. The hole is quite narrow at the bottom. Different timings and ground slope could or would effect hole shape.

I have noticed that there are several alloys which behave in similar way in mineral and normal mode. So in my opinion this GB hole in case of Vallon is quite wide. Fortunately old bronze and most hammered coins will not fall into it.

[Ferric Toes]

My grandaughter has a small 9 carat gold ring with 4 red stones with a total weight of 1.9gm and diameter 18mm. I checked the detection range on VMH3CS with both the Normal and Mineral settings. The Mineral setting was GB'd with a lump of Australian ironstone the same as with the tests on the 1 Lev coin. The range was the same in both settings at 11" (28cm), so there was no loss with this target. The TC of the ring was measured at 5.9uS.

Eric.

[green]

My grandaughter has a small 9 carat gold ring with 4 red stones with a total weight of 1.9gm and diameter 18mm. I checked the detection range on VMH3CS with both the Normal and Mineral settings. The Mineral setting was GB'd with a lump of Australian ironstone the same as with the tests on the 1 Lev coin. The range was the same in both settings at 11" (28cm), so there was no loss with this target. The TC of the ring was measured at 5.9uS.

Eric.

[ATTACH]45726[/ATTACH]

Interesting that you don't loose any detection depth. Wouldn't expect much signal lose in mineral setting with the ring. I loose a little when not in the hole because of noise increase with GEB on. Maybe Vallon doing something different?