Nfd 90 Metal Detector

[Sven1]

After a couple days of field testing the NFD90 in our soils it is totally different than testing on the bench.
Reminds me of a Garrett Ground Hog air and field testing in the red clay soils when living in Georgia.
The GH had superb air tests in TR mode, just couldn't get any depth in actual soil hunting.
I experienced the same with the NFD90 in our Canadian sandy dirt soil with some magnetic sand mixed in.
In static mode, NFD90 was too sensitive to changing ground conditions, like the old VLF/TR detectors in TR disc mode. Was constantly adjusting the tuning to compensate. In Dynamic mode it was more stable due to its auto tuning. Quarter coins barely made any threshold changes at 4", nor did pull tabs. Any other targets, were loud and could not determine size of the target. Canslaw, small, foil, crunched up foil was driving me crazy, at 4" it was still loud in Static mode. If I switched to Dynamic mode, they sounded more like good targets. 

As for finding iron, did not find any nails, hairpins, wire. Just some deeper steel cans and bottlecaps at 4". If there would have been a coin type object near one of those pieces of iron, they would not break thru the threshold null the iron creates.

I am concluding the NFD90 is not the ideal detector for coin and jewelry hunting in schoolyards or parks in our part of the world.  In other parts of the country and USA, the soil conditions might better suit the NFD90.  

Just want to add that not all brands or models of detectors work well here in Canada made before 2010 but,  are found to be superb detectors in the US.  

[ysabxe]

Sven, in miniral soil you need to use Dynamic mode. Modern sites are hard to hunt... but for best sepparation on low conductors we can't cut foil. I duged coins from 9" in black soil, just need to here faint thrashold. Try to hunt with it more on other sites. When you do GB coil should be not very close to ground. All your info is taken into account! Will do some changes to improve signal ID on depth. Conception of NFD 90 is not depth monster but it has max depth on iron infested places. Will do video test in real conditions and show what it finds 

[Sven1]

In modern sites with lots of foil and aluminum canslaw and no disc to eliminate it is not fun to hunt in with any detector. Just too bad too many people have no respect when it comes to properly disposing of their trash.

Next time I head down to Buffalo, NY if there is no snow or ice will give it another test. Soil conditions are different and will have to locate some old ground.

 

[Sven1]

Weather permitting, over the next few weeks will try a 100-150 year old farm field that is not polluted with foil and aluminum trash.  May find some relics or coins lost by the loggers or from the settlers. Maybe a better enviroment to try the NFD90 at. Just a lot of hot rocks to deal with in many of the  fields.

[kac]

I am curious about this machine still but hesitant as high frequency machines get slaughtered here when the ground is wet due to high iron content here in new england. When its dry I have no problems picking out targets with 56khz or even 40-45khz on d2 but start hunting near the wetlands or after a good rain the high frequencies tend to be too noisy. Tesoros I have at 14 khz and 17khz do very well and D2 I end up using mostly 13khz smf or mono.

Average for older coins tend to be in the 6-10" range but sometimes bit deeper here depending on area and previous activity.

Still wondering if your machine would do better in the 10khz range and concentric coil. That I think would make it a nice relic machine in this neck of the woods.

[palzynski]

Looking fwd to see NFD90 field tests in mild soil ( with and without iron trash ) , as I only have mild soil in my area .

Perhaps the NFD 90 will work better in mild soils than in mineralized soils 

 

 

 

[palzynski]

On 11/17/2023 at 9:32 AM, ysabxe said:

Will do video test in real conditions and show what it finds 

Yes videos test in real conditions are what we need . A side to side comparison with an iron trash specialist like an an Orx , Deus , and Deus2 would be a great plus . Personally in my European conditions ( nails beds , moderately mineralized soil )  I havent found a better machine than the 3 XPs up to now,  and I am curious to see if the NFD90 can do better than the XPs ..

[kac]

Not for nothing but I think there is a market for concentric coil machine at lower frequencies for iron infested grounds. Something the SMF trend seems to be skipping over as those machines seem to be more targeted towards beach hunting and general coin and jewelry hunting.

[EL NINO77]

The use of detectors with a very high frequency of over 30 kHz...also brings the difficulty of setting the detector to a highly mineralized magnetic/magnetite terrain with 4-5% or more percentages of magmetite in the terrain/..because extra high frequencies are much more sensitive to this type of mineralization terrain...

Hematite/iron terrain is not so sensitive to high frequencies and there high frequencies can work more stably/ similarly it is also in terrain that contains corroded iron... and there these high frequency detectors achieve good results...

74khz VS 14.4khz  ..note the stability of the detector at 14.4khz VS 74khz when I pass the coil around the edge of the black sand container...where there is no target...!!!

 

 

[kac]

Higher frequency means you have a wider gamut of detection on lower conductors (more spread on targets in that range). This crunches the mid and high conductors up high and making them more susceptible to iron wrapping. Other issue with high frequency machines is when you have rusty targets with halos they will respond to those too aggressively when the ground is wet which will smother other targets nearby. Using a dd coil will make that even worse as dd's tend to be very perpendicular in detection.

Big question is then is the NFD 90 chasing the nugget hunter market in mineralized soil as your comparing it to the Orx with HF coils OR are they pursuing the relic hunters looking for coin sized targets in iron infested grounds?

Prospecting machines can be used for relic hunting, I often use my Gold Racer for that but not around a 1700's barn or old cellar hole from a house that burned down and especially not after a soaking rain.