Vallon VMH3CS Mine Detector

[kingswood]

Looks very professional.
I hope they work well on the beach.

[Ferric Toes]

Standard headphones for the VMH3CS

I managed to put together a small plug in unit which enables the Vallon to be used with normal, inexpensive moving coil headphones. It also appears to work fine with an FM wireless module and FM headphones. The angle of the FM transmitter can be altered to give the best reception to the phones. I wonder how this wireless method will work on a wet beach where basically you have a huge ground plane which may affect the propagation from such small antennas.

Eric.

[kingswood]

I hope the 30cm coil is a good investment and gives some useful extra range. If I were in your shoes, I would be looking for the bigger nuggets too. I couldn't be bothered with the sub-gram bits.

Eric.

Happy to take what I can get....But hopefully the bigger coil gets a bit better depth to get anything larger and deeper!

[Ferric Toes]

The 30cm coil is here Looks very well made and bigger than it looked in the pictures!
Will get some photo's and a report next time I am out swinging
Thanks for the info about the probes Eric....I guess with the 30cm coil I am now looking for the bigger nuggets

I hope the 30cm coil is a good investment and gives some useful extra range. If I were in your shoes, I would be looking for the bigger nuggets too. I couldn't be bothered with the sub-gram bits.

Eric.

[kingswood]

The 30cm coil is here Looks very well made and bigger than it looked in the pictures!
Will get some photo's and a report next time I am out swinging
Thanks for the info about the probes Eric....I guess with the 30cm coil I am now looking for the bigger nuggets

[Ferric Toes]

I call dibs on the first Vallon EF 24 inch coil ha ha
I would also like to see how a small one would go on tiny pieces....

I am making a 15in coil which will give more range on coins and rings and it will be interesting to see if the range on, say, a 1gm nugget suffers. I suspect that it will.

I tried a ferrite cored probe that I made for the Vallon. This gives 8in range on a US Nickel, 7.0in range on a 10gm nugget, 3.5in range on a 1gm nugget, but there is no improvement on a 0.3gm nugget over the standard Vallon coil. I would say that this is because once the total decay of an object is about equal to the sample delay, that is what is limiting the detecting of the small object decay, more that the coil size. The pulsed magnetic field is certainly more concentrated with a small coil (everthing else being equal) and it may lift the tail end of the decay just sufficiently out of the noise to be observable, but shortening the delay will have a much more noticeable effect. Unfortunately this is not possible with the Vallon, except maybe for the Vallon firmware experts.

Eric.

[TH'r]

One thing you could try regarding the EMI on one of the Vallons is to check the channel settings to see if they are different.
On the one that is less affected by EMI set the mode selector to the speaker symbol. Press C and keep it pressed. After 3 seconds you get a short beep, but keep pressing C. Two LEDs should eventually light, 12 being one of them, but ignore this one. Note the LED number of the other one.

Switch off the first detector and go to the noisy one and repeat the process. If it settles at a different LED number, press either the + or - button so that the channel LED number is the same as te first detector. Switch back to the normal mode and see if the EMI is any better. Any channel change is stored on switch off, so on further use it will be the last change that you are working with.

If there is no improvement in EMI, then there could be a difference in the firmware settings of the two.

EMI is a problem for me in, or near, my workshop. No change in channel setting will cure it and I have not yet found out what the source is. Whatever causes it, goes off after 5.30pm and then the Vallons are quiet. It must come from an adjacent shop; maybe my wife's. I can hear it quite loudly on a medium wave radio and during the day it blots out all but the strongest stations. I use a 14in search coil as a loop antenna, so it is definitely the EM noise that plays havoc with the detectors. I'll have to find a portable radio with ferrite antenna and do some direction finding.

Eric.

Hello Eric; Tried this experiment with the following results. When I held "C" down in volume mode I got LED's 6789 followed by 2 & 11 (not 12) on the less sensitive to EMI Vallon. On the more sensitive to EMI one I saw 6789 followed by 9 & 13 (not 12?). I changed the channel to #2 but there was no improvement in the EMI situation.

[kingswood]

Great Report 6666
That all sounds very promising! I noticed the max. sensitivity thing too...machine false signalled even when a tiny bit of grass rubbed against the coil.
I love the pics too....the Vallon looks right at home

[Chet]

Hi 6666

Nice report.

Thank you,
Chet

[6666]

My day out in the Victorian Goldfields with my Vallon VMH3CS

My day out in the Victorian Goldfields with my Vallon VMH3CS


Recently I said that my Vallon was a dud, that turned out to be incorrect, what was happening was the machine was ground balancing almost instantaneously on the soil in my backyard and that combined with the poor description in the manual lead me to the wrong conclusion,


After watching Kingswood's video, I tested my machine on 3 tubs of goldfield dirt with added hot rocks, (these hot rocks were found with my 4500).
THEN, I could see a difference in the time the machine took to ground balance on the 3 different samples and when I waved the coil over the other 2 then they reacted and needed re balancing.


But the machine only takes a couple of bobs of the coil and its done with GB, very quick.


These 3 samples were from Castlemaine, Beechworth and Heathcote Goldfields in Victoria.




So last Saturday I travelled up to Wedderburn which is over 550 Km round trip for me to test my Vallon on the hot mineralised ground there, even my GPX4500 has a hard time there, unfortunately there were hundreds of detectorists in the area as a detector jamboree was being held in the town that weekend.


The weather conditions are important I think, it was a hot 35' C and hotter temperature in the direct sun with a strong wind blowing the dust around, it has not rained there for some time so the ground was very dry and dusty and hot to touch with your hand, I didn’t spend a lot of time testing as it was very hot and the 25 mm March flies were biting big chunks out of me, at least the mosquito plague from the last few months has died off.
The machine needs to be re tested in the winter on wet ground.


The public Goldfields are very restricted on where we can hunt, the area I chose to test was in a flattish long gully that had extensive workings, and had been thrashed with detector holes everywhere, I laid the machine on the ground for a few minutes to let it adjust to the temperature as it said in the manual, I also used the military headset which works quite well and fits ok with the straps on it, but would look better with headphones.


The ground there has a lot of large and small quartz in various colours from white through to pinks and iron stone and slates, dense hard pack clay and gravels, a scattering of scrubby bush and trees which gives a lot of bark and leaf litter and a small amount of dry grasses, I turned the machine to normal and let it do the self test and then to the last position and adjusted the headset audio level, then turned it to mineral and put the coil on the ground and let it settle, after pushing the “C”button and doing the correct ground balance procedure it only took 3-4 bobs and it finished the GB, very fast, after walking around for a short distance I noticed some ground noise so I rebalanced in that area and that fixed that, I did notice a bit more noise from around the ground at the bottom of tress , so I re balanced on that area and that fixed that noise to, again only took 3-4 coil bobs. I struck one area around a big tree base that was noisy, and that took the machine about 6-7 bobs of the coil to balance, so I guess the trees bring deeper rocks and soil to the surface as they grow ? but out in the open areas the machine ran very nicely and no EMI, I keep the machine on 12 , turning it up to max 14 did bring up the ground noise so kept to 12.


Time for gold nugget testing, I brought along several natural nuggets all found with a detector, ranging from 14 grams down to .1 gram, they were in plastic bags and just laying on the surface.


Needless to say the 14 grammer blew the headset off, the 1 gram very loud and getting down to my (.2) point 2 gram gave good signals with the coil off the ground a few inches, the (.1) point 1 gram gave a very tiny signal and if the machine was running with good balance and the .1 nugget was sitting close to the surface then you MAY get a diggable signal, it was very iffy.


I had planned to bury some of the nuggets but the heat and hungry march flies were making the conditions unpleasant so it was time to find somewhere to camp for the night and enjoy a few cold drinks, so in conclusion I was very happy with the way the machine worked and balanced to the ground conditions, even the other detectorists with gpx5000's and the latest Evo coils that I spoke to, were complaining about the ground conditions and noise.


So if the Vallon handles hot Wedderburn ground then I cannot see why it would not handle ground with lesser mineralisation, when the weather cools down a bit I'll be back for some more testing, one thing I forgot to do, and that was to throw a magnet on the ground, to see how it clumps.


It would be interesting trying other size coils but getting the shaft fittings would be very difficult.


The description in the manual only gives a partial GB description and needs to be improved, at a later time I will try the GB at home and try and see what number LED setting the machine chose for Wedderburn, I forgot to look at the GB LED while I was testing there, I did not try the manual fine adaption .
A couple of pictures for interest. 6666

[Ferric Toes]

I call dibs on the first Vallon EF 24 inch coil ha ha
I would also like to see how a small one would go on tiny pieces....

I have made a few ferrite probes that work well with the Vallon, and are equivalent to a smaller coil. I will see if any of these show improved performance on small nuggets and post shortly.

Eric.

[kingswood]

All we need is some alternative size coils and I am working on that. Eric.

I call dibs on the first Vallon EF 24 inch coil ha ha
I would also like to see how a small one would go on tiny pieces....

[Ferric Toes]

Great news, my Vallon does ground balance on the hot ground at Wedderburn, and runs very nicely, pictures and better report later.

Yes, that is great news and also look forward to a detailed report. It could be that more Vallons will be on their way to Oz before long to give the home bred detectors a bit of competition. They are certainly rugged enough for the bush environment. All we need is some alternative size coils and I am working on that.

Eric.

[kingswood]

Great news, my Vallon does ground balance on the hot ground at Wedderburn, and runs very nicely, pictures and better report later.

Excellent....Post a pic of your nugget finds

[6666]

Great news, my Vallon does ground balance on the hot ground at Wedderburn, and runs very nicely, pictures and better report later.