Cache Test

[Unregistered]

Don't write off the Saxon due to an old Arado not being up to spec. The quoted in soil range on a Sovereign was 11 inches for the 120 (its about the size of a U.S. 5 cents). You could certainly dig old copper pennies at 12 inches+ and the 130 model was deeper again so start adding 50% and you get repectable coin depths and the larger coil on the Saxon would favour larger objects like the silver bar and cache.

[hung]

Esteban,

If you have the 08MI or MP10 2 boxes units by Mineoro, try this cache test. I believe they will easily pick this up. Actually 2 meters down would be a fair test for them. Specially for the silver cache. Pay attention to the small objects VU. It's got a tremendous sensitivity.
In 1969 with one of those, Mr. Anisio Trelha found a cache of gold coins from 120 m away. Since the long time buried target has an intense electric field around it , this triggered the auto mode in the detector and the VU led him to the direction over the target.
Unfortunately I don't have my 08MI anymore. If for some reason you cannot do this test, I'll ask my friend Celi who's got an MP10.
AFAIK the Mineoro's 2 boxes are one step above anyting I know.

[Unregistered]

Don't write off the Saxon due to an old Arado not being up to spec. The quoted in soil range on a Sovereign was 11 inches for the 120 (its about the size of a U.S. 5 cents). You could certainly dig old copper pennies at 12 inches+ and the 130 model was deeper again so start adding 50% and you get repectable coin depths and the larger coil on the Saxon would favour larger objects like the silver bar and cache.

Personal opinions dont have much in common with science. Good measurement test will determine how deep is the Saxon indeed. If the Arado can find coin at 12"+ then the Saxon should get them at 18"+(50% more depth)
Well that claim is against the laws of phisycs. And by the way the Arado does not have big enough search coil to get to that depth.
Another fact. The Arado comes with 8"-10" coil as far as I am aware. The Saxon with 12". The difference between 8" and 12" is 50% which suggest that the difference in sencitivity will not exeed 25% (not 50% as they say)
I believe the claims about the Saxon are not based on real facts.
If someone pay 1700£ it will be hard to admit that it was not worted.

[Unregistered]

Esteban,

If you have the 08MI or MP10 2 boxes units by Mineoro, try this cache test. I believe they will easily pick this up. Actually 2 meters down would be a fair test for them. Specially for the silver cache. Pay attention to the small objects VU. It's got a tremendous sensitivity.
In 1969 with one of those, Mr. Anisio Trelha found a cache of gold coins from 120 m away. Since the long time buried target has an intense electric field around it , this triggered the auto mode in the detector and the VU led him to the direction over the target.
Unfortunately I don't have my 08MI anymore. If for some reason you cannot do this test, I'll ask my friend Celi who's got an MP10.
AFAIK the Mineoro's 2 boxes are one step above anyting I know.

I think we are missing the point here.
The cashe test in garysdetecting was done with induction balance detector.
Now comparing induction balance against PI or LRL or any other is like star ship to a bull wagon.
It might be better to just run comarison between detectors build on the same principals and close phisical sizes for the search coils.

[Carl-NC]

I disagree... only because, so far, nothing at all will detect the cache, at least in my case (I don't have a Nexus). So my goal is to find something that will detect it, whether VLF or PI or BFO, regardless of coil size, or operating mode.

[Leto]

Carls MD colection

So to make this test realy 100% comparable because of numerious factors as soil mineralisation, hoard composition-distribution, RF interference and operator subjectivness
..... we will all have to send our best detectors to Carl

[Unregistered]

I disagree... only because, so far, nothing at all will detect the cache, at least in my case (I don't have a Nexus). So my goal is to find something that will detect it, whether VLF or PI or BFO, regardless of coil size, or operating mode.

David from Dixie Metal Detectors have Nexus in his shop. May be you can talk to him about this test. Perhaps he would land it to you for the test.

[Ferric Toes]

Hi Carl and All,

I suspect that most available PI's would fail to detect the cache as the TX pulse would be too short. A standard Quarter requires a TX pulse of 800uS to get maximum signal, and a silver quarter would require considerably more. I have one somewhere, but having recently moved, I'm having trouble locating it as well. I did find a Silver Dollar, and this required a TX width of 4mS on my test rig! Modify a Hammerhead to give 2 - 4mS and use a 48in diameter coil, and I bet you will find your cache easily. The sampling and integration values will need to be changed considerably as you will be running at a low pulse rate. You should be able to increase coil inductance considerably too, which will help. Even if sampling begins at 100uS, there is loads of signal there.

My experience with a quantity of coins is that the decay time for the quantity, is much the same as for a single coin, because of the relatively poor electrical contact between individuals. What does go up though, is the amplitude, because of the larger effective surface area.

Eric.

[Carl-NC]

Hi Eric,

Moved again? Where now?

I am in the process of modifying an old HH prototype for this test. I changed the 555 to run 100Hz, then started having all sorts of problems. Just before I went on vacation last week, I discovered a speck of solder that was intermittingly (sp?) killing the 555 output, drove me nuts for 3 weeks.

Hopefully can now get this thing finished. Hadn't expected to run such a long pulse width, was thinking more like 0.5ms. But OK, I'll make 0.5ms the bottom end of the range. Will also make the sample go up to 100us.

Thanks for the input.

Regards,
Carl

[Unregistered]

baby buggy parts

Had a look at nexus last week. Looks like another dog to me. Hardware looks like its from baby buggy. Has everything but wheels. If I buy one in US can I get parts from mothercare. I think Unregistered posts on this forum are to much open to abuse by low budget manufacturers. Unregistered = Nexus Guy

[Carl-NC]

One reason I've allowed Unregistered posts, is so folks can post anonymously if they feel the need to do so, for whatever reason. As long as Unregistered remains civil and doesn't abuse this option, I will leave it as is. Also, I welcome participation by all manufacturers, regardless of their budget.

[Ferric Toes]

Hi Eric,

Moved again? Where now?

Hi Carl,

I'm back in Oxford, the home of PI, just a couple of miles from the city centre. Had to move for family reasons, but I have a nice workshop in a quiet location, and a big field out back which will be good for testing. No fun moving and setting up again, but I am now fully operational once more.

Eric.

[Unregistered]

Had a look at nexus last week. Looks like another dog to me. Hardware looks like its from baby buggy. Has everything but wheels. If I buy one in US can I get parts from mothercare. I think Unregistered posts on this forum are to much open to abuse by low budget manufacturers. Unregistered = Nexus Guy

Looks like the Nexus guy is talking himself down or what?????????

[Unregistered]

Hi Carl and All,

I suspect that most available PI's would fail to detect the cache as the TX pulse would be too short. A standard Quarter requires a TX pulse of 800uS to get maximum signal, and a silver quarter would require considerably more. I have one somewhere, but having recently moved, I'm having trouble locating it as well. I did find a Silver Dollar, and this required a TX width of 4mS on my test rig! Modify a Hammerhead to give 2 - 4mS and use a 48in diameter coil, and I bet you will find your cache easily. The sampling and integration values will need to be changed considerably as you will be running at a low pulse rate. You should be able to increase coil inductance considerably too, which will help. Even if sampling begins at 100uS, there is loads of signal there.

My experience with a quantity of coins is that the decay time for the quantity, is much the same as for a single coin, because of the relatively poor electrical contact between individuals. What does go up though, is the amplitude, because of the larger effective surface area.

Eric.

Hello Eric.

My new test site is in the back garden of Mike Longfield. He is a very old detector dealer in the UK. He lives near Birmingham.
You could get there if possible and test you detectors. The cashe is 1kg. of various bronze-copper-silver coins and very few modern iron based 2 pence coins all at 24" depth.
You can see pictures of that test site in www.nexusdetectors.com the Tests page.
If you do go there it will be interesting to see how the PI detectors will respond to that test.
Best regards.
Georgi, Nexus

[Carl-NC]

When I went to Radio Shack to pick up my cabinets, they had a Discovery 2200 in the storage room, just laying there, no box. I asked if it worked, he said, "Yup, it was the floor demo. No box or papers. I'll sell it for $29." I couldn't resist. It won't detect the cache either.