NEXUS ULTIMATE, your opinion, please

[wam]

...Georgi tells me that he once issued a challenge for anyone to try and beat the Nexus in a real test in the field. Apparently the challenge still stands. You can contact Nexus for details.

Would You know the target conditions for challenge ... my MD takes 25C coin from 51cm in air. If You know what has to be faced in challenge then I better try it before make myself idiot.

[Qiaozhi]

Would You know the target conditions for challenge ... my MD takes 25C coin from 51cm in air. If You know what has to be faced in challenge then I better try it before make myself idiot.

As I said ... you need to contact Nexus for details.

[kt315]

As I said ... you need to contact Nexus for details.

Qiaozhi, is this subject so interesting for the topickiller? why he does not reply? why he is silent in time we are so hot fussy on nexus? stop pls and wait WHAT TOPICKILLER WANTS TO HEAR NOW FROM THE MEMBERS.

[Max]

Qiaozhi, is this subject so interesting for the topickiller? why he does not reply? why he is silent in time we are so hot fussy on nexus? stop pls and wait WHAT TOPICKILLER WANTS TO HEAR NOW FROM THE MEMBERS.

Hi kt315,
you meant there's a "challenge" about detectors performances in air ?

or it's for underground targets ?

regards
Max

[toni_lxg]

Wich detector for coins

Would You know the target conditions for challenge ... my MD takes 25C coin from 51cm in air. If You know what has to be faced in challenge then I better try it before make myself idiot.

Thank you to all for the information. Which model of MD you make these tests?
- Its seems that to use NEXUS is much difficult...i don't know which detector to choose for coin search, Wich one is the best?? what do you think guys?? for daily and professional use

Thank you again

[Max]

Thank you to all for the information. Which model of MD you make these tests?
- Its seems that to use NEXUS is much difficult...i don't know which detector to choose for coin search, Wich one is the best?? what do you think guys?? for daily and professional use

Thank you again

Hi
depends: where are you going to search for coins ? at the beach ? or ancient stuff... say inland and hard soil with grass and lot of bricks and hot ceramics around ?

cause for beach I would go for a good PI , no dubt, cause of more depth performance and salt water ignoring features... but inland, with ceramics and bricks (someone here knows VERY WELL what I'm talking about... false signals from that stuff when using PIs!) I'll go for VLF no dubt!

about models... well... depends on budget: today you can find decent VLFs for less than 200usd also, even brand new; about PI you also can find good ones for some hundreds dollars or eur

if you want really good ones (will not talk of brands and models , it's easy to know which ones really shine) be prepared for many hundreds or thousand also dollars/eur expense

the "best" ones and also overpriced ones... thousands eur/dollars are big deal for many people; the best one is the one you can really enjoy and dug something interesting and that's not mean you must buy a top-of-the-line MD...

[detectoman]

HELLO MAX, i´m jealous of see you of new here, jajaaj, i send you my embrace
holaaa max yo estoy gustoso de verte de nuevo aqui, yo te envio mi abrazzooooo

where going you in all this time? jajajajajajajajajaj

[Max]

HELLO MAX, i´m jealous of see you of new here, jajaaj, i send you my embrace
holaaa max yo estoy gustoso de verte de nuevo aqui, yo te envio mi abrazzooooo

where going you in all this time? jajajajajajajajajaj

Hola detectoman
yo te envio mi abrazo también

where ? well... had some connection troubles...

no, really, had so many things to do that could be almost impossibile follow the forum and various threads as before, of course I read some stuff from time to time but sometimes with months of intervals between readings!
last time before I retrieve the password and posted stuff (yesterday) was from an hotel in central London... during the night... too much curiosity about new trends here

[goldfinder]

Q - galvanized sheet metal

Firstly, I must confess that Georgi at Nexus is a friend of mine. Although I haven't used the final product (as displayed on the Nexus website), I was with Georgi when we did some field testing of the prototype. It's a real beast. We originally did some searching at a river site by the Thames using a 9" OO coil. Georgi found a really strong deep signal and insisted on digging it out, whatever the depth. Eventually we got to the bottom of a waterlogged hole, and it turned out to be a chunk of galvanished roof panelling; which of course is non-ferrous, buried at a depth of 1m. The Ultima coil was able to detect the same target with ease. The prototype was a single-frequency version. According to the website, it can detect a roman helmet at 190cm (6.2 feet) in normal soil conditions. I can quite believe that.

Q- galvanized sheet metal is zinc coated sheet iron here in the USofA and therefor very ferrous.
Goldfinder

[Qiaozhi]

Q- galvanized sheet metal is zinc coated sheet iron here in the USofA and therefor very ferrous.
Goldfinder

The metal we recovered from the 1m deep hole was not rusty, and definitely not ferrous.

[Qiaozhi]

The metal we recovered from the 1m deep hole was not rusty, and definitely not ferrous.

More detailed information from Georgi:

"The story with the metal roofing we found is this.

Any kind of Iron based metal target that is coated with non-ferrous metal regardless which exactly is detected by the metal detectors as non-ferrous, because the detectors do not react on what is in the depth (construction) of the targets but on their surface layer. It is on the surface where the Eddy currents are most powerful.
This is the very reason why coins covered with patina are more difficult to detect than clean coins. The patina is not conductive and it obstructs the formation of Eddy currents."

[ivconic]

More detailed information from Georgi:

"The story with the metal roofing we found is this.

Any kind of Iron based metal target that is coated with non-ferrous metal regardless which exactly is detected by the metal detectors as non-ferrous, because the detectors do not react on what is in the depth (construction) of the targets but on their surface layer. It is on the surface where the Eddy currents are most powerful.
This is the very reason why coins covered with patina are more difficult to detect than clean coins. The patina is not conductive and it obstructs the formation of Eddy currents."

That makes pretty much sense, agree.

[Max]

More detailed information from Georgi:

"The story with the metal roofing we found is this.

Any kind of Iron based metal target that is coated with non-ferrous metal regardless which exactly is detected by the metal detectors as non-ferrous, because the detectors do not react on what is in the depth (construction) of the targets but on their surface layer. It is on the surface where the Eddy currents are most powerful.
This is the very reason why coins covered with patina are more difficult to detect than clean coins. The patina is not conductive and it obstructs the formation of Eddy currents."

Hi,
yes, I agree and think the same, but we must consider that in not disturbed (for many centuries) soil the target e.g. coin could create a "halo" around , that's not about LRL or something mystical thing but just "migration" of metal in the sorrounding soil in chemical compounds and salt that will change not only the electrical conductivity of soil in direct contact with target but also change the magnetic properties of that small portion of soil, thus creating an increased signal

btw I assume that Georgi is an expert of what I'm talking about and also knows about magnetic detection (mostly by PI but not only) of hot rocks and bricks where there are virtually no eddy currents but detectors got signals from them cause of magnetic properties of aligned micro magnetic dipoles inside the ceramics or hot rock...

thus... halo works the same, it's a dispersion of metallic compounds that can give a stronger signal for such a target, and that's include mostly silver and copper or bronze items cause we know halo is not easy to develop around gold items cause of chemical behaviour of gold

these halo spots make that e.g. silver coins with patina produce less eddy currents at exposed surface but stonger magnetic interaction with tx field resulting in stronger signal and phase shift of what we can have from same target , same position, same orientation and depth in same soil but "disturbed" and "fresh" buried

so I think that patina it's not always a problem when its creation is related to halo formation during very long time and oxidation processes

regards
Max

[pelanj]

More detailed information from Georgi:

"The story with the metal roofing we found is this.

Any kind of Iron based metal target that is coated with non-ferrous metal regardless which exactly is detected by the metal detectors as non-ferrous, because the detectors do not react on what is in the depth (construction) of the targets but on their surface layer. It is on the surface where the Eddy currents are most powerful.
This is the very reason why coins covered with patina are more difficult to detect than clean coins. The patina is not conductive and it obstructs the formation of Eddy currents."

I would agree with the first part. The layer of zinc can be thick enough to show only as zinc at the MD frequency.

But for the second part - does the patina work as a shield? I would rather doubt. If the layer is not conductive, then the eddy currents would appear just below that layer as it had not been there at all...It seem I miss some points or the statement is just not true. It seems to me as mixing apples and oranges in that paragraph.

I might be wrong, I am ready to hear your arguments.

[ivconic]

I would agree with the first part. The layer of zinc can be thick enough to show only as zinc at the MD frequency.

But for the second part - does the patina work as a shield? I would rather doubt. If the layer is not conductive, then the eddy currents would appear just below that layer as it had not been there at all...It seem I miss some points or the statement is just not true. It seems to me as mixing apples and oranges in that paragraph.

I might be wrong, I am ready to hear your arguments.

It is fact that "clean" coins are easier to detect than ones with patina layer.
But there is also another fact; coins buried in soil for long time are also easier to detect than "freshly" buried coins.
Usually patina layer do develop on coins which are buried for long time.
But also the "hallo" effect appears on such coins.
So it is pretty complicated now. Patina prevents better detection - while "hallo" effect supports better detection.
At the end, better detection is dependable on several factors - not only one.
On other hand; eddy currents can easily develop and flow on straight and clean surface.
So, as you see; it is all conditional.
Georgi was generally very right, speaking about relation between mass and surface of item in soil.
It is not so important buried object to be massive as it is desirable to be turned face up with broader side (parallel to coil surface) - so eddy currents to evolve easier and feedback stronger response back to coil.