Vallon VMH3CS Mine Detector

[mschmahl]

They are both exatly with the same depth (if you use same settings). I have wrote to Vallon, they confirmed that there was a special UK-military version without land and Sea setting, without automatic-frequency adjustment and without the filter adjustment.

[daverave]

i was once sent a vallon to field test for someone and its not a bad machine...very stable with good depth.

[kingswood]

Reply from Vallon in regards the 30cm search coil....Total cost including carry bag and delivery is about 875 Euro !!
I wonder how much depth the 30cm coil would gain in detection over the standard coil. Looking at some of the mine test reports the larger coil did hit targets at deeper depths, but at a loss of sensitivity to smaller targets....
I am not sure if the cost justifies the experiment !!

[Alexismex]

Think it is a reasonable good cost for a military stuff

[kingswood]

Think it is a reasonable good cost for a military stuff

The coil will cost more than I paid for the 2 detectors !!

[Ferric Toes]

The coil will cost more than I paid for the 2 detectors !!

Another way of looking at it; you have only got to find 25gm of gold and the coil is paid for.

Eric.

[kingswood]

Another way of looking at it; you have only got to find 25gm of gold and the coil is paid for.

Eric.

Optimism!...I like that!!
How much deeper should I expect with the 30cm over the standard head...all things been equal??!

[green]

Optimism!...I like that!!
How much deeper should I expect with the 30cm over the standard head...all things been equal??!

I have been using a 200mm diameter coil and wondered how much I would gain with a bigger and smaller coil. I did a test awhile back comparing a 200mm coil with 133mm and 300mm coils. Inductance and current profile the same for the three coils. Charted target distance vs integrator out. Got similar results to a chart posted in other threads. Don't know if it relates to the Vallon coils. The amplitudes crossed at (diameter A + diameter B)/4. Gain on some targets, lose on others. Still don't know what size to end up with.

[green]

Another way of looking at it; you have only got to find 25gm of gold and the coil is paid for.

Eric.

Approximate. Looking at chart reply #593 the 300mm coil would be better than the 200mm coil for nuggets over 1gram, worse for nuggets less than 1gram? Something to try, find what size nugget can just be detected at(diameter A + diameter B)/4. I've found coil circumference converted to round to work for odd shaped coils.

My thoughts, appreciate being corrected if wrong.

[6666]

I have been using a 200mm diameter coil and wondered how much I would gain with a bigger and smaller coil. I did a test awhile back comparing a 200mm coil with 133mm and 300mm coils. Inductance and current profile the same for the three coils. Charted target distance vs integrator out. Got similar results to a chart posted in other threads. Don't know if it relates to the Vallon coils. The amplitudes crossed at (diameter A + diameter B)/4. Gain on some targets, lose on others. Still don't know what size to end up with.

Hi Green good chart thanks, I've been going over some of your charts recently
where do you place the target when you take a reading, is it stationary ?
Is your integrator a 1c or 2c ?
thanks

[green]

Hi Green good chart thanks, I've been going over some of your charts recently
where do you place the target when you take a reading, is it stationary ?
Is your integrator a 1c or 2c ?
thanks

1C integrator. Stationary, most of the time over the center of the coil spaced to give a maximum signal without the over ranging the amplifier. Depending on the coil connected(1.5 to 12 inch diameter) to the bench circuit it might be positioned closer to the edge to get a good signal. Or I might change coils. The amplifier full scale is 2.5 volts. I found my scope can effect the slope if the scale is less then .5 volt/div. so I try to position the target for at least 1 volt peak change, no target to target. It's a lower cost scope but does an acceptable recording.

Just described what I do when charting decay slope out of the amplifier, no integrator. Charting amplitude vs distance. 1C integrator, target stationary located at defined position over center unless charting amplitude off center which would be defined.

[kingswood]

Sheepishly mentioned to the wife that I was buying a larger coil....Told her the price and she said "Oh I thought they would be more than that"...God love her
Have ordered and will be shipped soon. Cant wait to try it!!

[kingswood]

Interesting morning out detecting!....Went early as we are heading for 37 degrees again!
Tiny staple at 6 inches....no doubt about the response from the Vallon.
Took my new 0.1g nugget with me (thanks ebay!...if you can actually call it a nugget, more like a flake!!)......on the ground can detect it with coil raised about 3 inches above it. Buried, it makes a decent signal at about 2 inches in mineralised mode.
Had the biggest loudest response from the VMH3CS that I have experienced so far!....Got quite excited....Dug down and it became louder!....at about 2.5 feet, found the side of a rusted old oil can
Depth was very very good! I can confirm that the screech the Vallon makes on lead, alloy, gold and steel all sounds a bit different...I think...

[6666]

Interesting report thanks
I've been crook for last couple of weeks so have not ventured out any.
Dont fancy that 37', we have 5 days of +30 next week
What sensitivity setting (LED) did you have the machine set to for the .1 at 2 inches ?
thats not bad.

With mine with sens LED at 12, my 1.2 gram detects at about 6 inches in air in normal mode.

[kingswood]

Interesting report thanks
I've been crook for last couple of weeks so have not ventured out any.
Dont fancy that 37', we have 5 days of +30 next week
What sensitivity setting (LED) did you have the machine set to for the .1 at 2 inches ?
thats not bad.

Standard sensitivity setting...the default one that it sets to when you switch on. I think it is 12 out of 14. I did find before that when I increased the sensitivity. I got more false signals from rocks, so have kept it pretty much set to "standard". When i did try that though, I was in a really rocky area, so will try and increase it again on "better" ground.
We would love a day below 30...cant remember the last one !!