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Detector With Good Discrimination


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Hi guys!

I asked for advice on choosing a forum detector (http://www.detectorprospector.com/forum/topic/91-choose-detector/#entry632. I was planning to buy an inexpensive VLF detector. But I got a bonus at work and bought a used GPX 5000. I went with this detector on some old gold deposits. I found 6 nuggets total weight of 6 grams.

GPX 5000 detector is good, but I dug a lot of iron objects. I lost a lot of time digging for iron things. Gold mines are very old, so the soil forged nails, small pieces of wire.

I think in addition to the GPX 5000 I need a second detector. The main requirement for the detector - good discrimination.

Now I look at the detectors:

1. Whites MXT

2. Whites GMT - because things are little nuggets (less than 1 gram). Am I right to think ?: GMT will be deeper than GPX to 0.5 grams of gold nuggets?

3. Minelab X-terra 705

4. Minelab Explorer SE

5. Fisher Gold BUG Pro/F19. This detector (thanks to Steve for information) shows VDI targets all metals mode, it's good!

I know what to look for in the "all metal" because discrimination reduces sensitivity. But I would like to be able to include disc. whenever I want.

What do you think of the detector to hunt for nuggets in the tailings. Any thinking please!

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For years I've used a White's MXT.  For tailings the 4X6 Shooter is my choice.  For parks the 6X10 DD coil is great for jewelry/coins. With those two coils it's like having two detectors in one.

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There simply is no perfect answer to this because many detectors would do well for this task, including many not normally regarded as prospecting detectors. I think there are three categories a prospector should consider:

1. A good pulse induction detector. You need these to ignore hot rocks and ground a VLF cannot penetrate well. The Minelab GPX 5000 is the obvious example with the Garrett ATX serving as a budget alternative.

2. A detector very hot on small gold. Pulse induction detectors weak spot is very small or very porous and wiry gold. The Gold Bug 2 and White's GMT have always been the recommended models but I would now add the Minelab SDC 2300 to the short list as a "hot PI".

3. A good general purpose VLF with good discrimination and with good sensitivity to gold. There are many detectors that may serve but I am going to narrow the field by adding hurdles.

a. The unit should be able to run in a single frequency running between 10 and 30 kHz. Single frequencies pack more punch than multi frequency units on gold items. That eliminates the Explorer from your list as being a multi frequency model, and the GMT for being on the "hot" list.

b. There are just too many detectors to choose from, so let's really narrow it down to bang for the buck. It can't make our short list unless it can be had brand new with warranty online for under $800

Looking at your list then I would focus on the MXT, 705, and Gold Bug Pro/G2/F19. The smart thing to do is just line up the feature list for all three and see if they have things that appeal to you for other purposes. The 705 for instance for coin and jewelry detecting has numerous tone and notch selection options making it the most feature rich of the three. The MXT falls in the middle with the First Texas machines being more spartan.

I will add a detector to your options just in case. The Garrett AT Gold. In general I would pass because it is waterproof and so it has underwater connectors for the coils and headphones that are problematic if you do not need a waterproof detector. However, if you want the detector to be safe in pouring rain or wading in and around streams then all the sudden waterproof to 10 feet looks real good.

A closer look at discrimination options on the four:

MXT can reject a ferrous target by a. setting a simple knob to just barely eliminate the ferrous target or b. set the knob to give a low tone on ferrous targets and high tone on non-ferrous targets and c. always give a target id on screen. You get three possible ways to reduce digging nails.

AT Gold while in all metal prospect mode allows you to set an adjustable "iron audio" to give a low tone on ferrous targets plus give an on screen target id. You can also switch to a normal disc mode and reject nails. Again, you get three possible options.

Gold Bug/G2/F19 while in all metal mode put the target id on screen. However, to separate by tones you must switch to discriminate mode. The MXT and AT Gold differ somewhat in that they have all metal "mixed mode" capability that layers a ferrous tone response on top of the all metal channel. This means those two models offer more nuance in the way of audio options for those that prefer to hunt by ear. Gold Bug/G2/F19 tend to mean more screen analyzing after audio target acquisition.

X-Terra 705 in all metal Prospect Mode has an adjustable "iron mask" that can be set to reject ferrous targets while in all metal mode. There are no tones, the target either breaks up or is eliminated. There is also no on screen id while in all metal. To get these options you must switch to the less powerful discriminate modes. However, while the 705 is the most limited in this regard the iron mask while in prospect mode does get the job done.

I will leave it at that because they are all good detectors for the task. You can get a Gold Bug/G2/F19 or X-Terra 705 or AT Gold or MXT and be well served by any of them. They all have very powerful all metal modes and they all can be used for just about any type of metal detecting. They can all be had around the $700 mark more or less and all can actually serve well for people who just want one detector to do all the detecting they do. I highly recommend people interested look very hard at all the things each model offers for extra features in making a decision as that is where they all differ the most. For instance, the 705 and MXT both have decent beach modes that would make them a better choice for somebody near the beach compared to the Bug or AT.

Short list in alphabetical order, online prices:

1. Fisher F19 (10" x 5" DD coil, 2.8 lbs) $749
2. Garrett AT Gold (8" x 5" DD coil, 3 lbs) $679
3. Minelab X-Terra 705 Gold (10" x 5" DD coil, 2.9 lbs) $729
4. White's MXT Base Model (9.5" Concentric Coil, 4.2 lbs) $729*

*MXT All Pro with extra features and 10" DD coil $799

Final note - it looks like we will be able to add the Makro Racer to this list in February. Some may also question why I left the Tesoro Lobo off the list. In my opinion the Lobo is a good detector but Tesoro has opted out of keeping up with the times. You get to chose between an all metal "dig it all mode" or a hobbled discrimination mode. Tesoro has decided to ignore prospectors for twenty years so I am ignoring them going forward.

For more details and information see Steve's Guide to Gold Nugget Detectors The subject has also been discussed recently on other threads such as the one at http://www.detectorprospector.com/forum/topic/506-are-we-missing-nuggets/

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I have a GMT and an AT Gold. I love the GMT for sensitivity and ease of operation, but I find the AT Gold outshines it in very trashy areas. The area that I mostly hunt in has a ton of brass shells and bullet frags, along with plenty of square nails, tin foil and various other pieces of trash. The variable discrimination, iron audio and visual ID on the Garrett just makes it easier to decide what to dig and what not to dig.

 

When I bought the AT Gold I had narrowed my options to either it, or the Gold Bug Pro. It was a tough decision between the two as they both seem to have very similar features and plenty of great reviews. At the end of the day I decided the Garrett made a slightly less annoying noise than the GB Pro! The headphone socket on the AT is an annoyance, but there is an available adapter to convert to 1/4" jack (if you don't mind spending an extra $40).

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Thank you all!

I purchased used ML X-Terra 705. Coil DD 10.5 "7,5 kHz.

According to the descriptions I liked MXT but ML I bought inexpensive!

If I buy a coil of 18.75 kHz ellipse, it will greatly increase the depth to small targets?

Small targets for me is 0.3-0.6 g nuggets.

Testing the air coil 7.5 kHz showed a depth of about 1 inch by a nugget weighing 0.4 g

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