Dutchman4

Despite the problem it still appears to be useable though. From the looks of the fail pattern it could be a display driver or cable problem also, maybe? Maybe a gentle reseat of the cables could resolve it. The screw heads in the picture appear to be corroded like this was a salt water beach machine. Good luck.

So I picked up a GP3000 a few days ago including an assortment of coils. This NF 17x11 is the only mono coil in the bunch and it appears to be an older model with a fiber glass body. Do any of you old timers have any experience with this coil regarding depth (on 2g+ nuggets) and stability vs the more modern coils?

That is generous of you Dave and I may take you up on that offer when I make a return trip to the patches. At least it will settle my mind on what could be at depth.

Kingswood, I see in your list that you own the GPX6000 and GP3000 so you would know if the GP3000 with the 24x12 ufo mono would have a depth advantage over the GPX6 on larger gold. If this advantage is minimal then I will just get the 17x13 mono for the 6000 and hope it adds some depth over the stock 11.

Hey Rob, So it appears you are saying that a stock GP3000, with the right coil, wont have a significant depth advantage over a 6000 with the 17x13 coil, on 3g+ nuggets.

It is obvious to me that these patches are virgin ground since I am finding multiple nuggets up to 2.5 grams in size that should have been found by any PI machine and probably most VLF also. The average depth of these nuggets was 5 to 10 inches.

I have a GPX6k that I have had good success with over the last few years. I have found several patches that yielded in the range of 8 to 15 nuggets each with biggest ones at 1.7g and 2.5g. I have considered going back to these patches and start layering off the surface to gain more depth but that sounds like a lot of work. I have also considered getting the 17x13 coil for the 6k to gain more depth but the reported depth gain appears to be only about 1 inch over the stock 11 coil if that is true. Another option I am considering is to purchase an older Minelab PI and combine it with the best coil for depth, so that I can use it to go over patches (that I have cleaned out using the 6k) to find larger (3-5g and larger) nuggets at depths deeper than the 6k is capable of. So just to be clear I want a machine that is dedicated/configured for increased (at least 3+ inches deeper than 6k) depth on larger gold, has a stable threshold and the ability to handle ground mineralization and hot rocks better than the 6k. It does not need to be an all around machine that can also find smaller shallow gold since I have the 6k for that, but if it can then that would be a bonus. I want to limit my budget to a max of $1500. After some research and input from friends I have been advised to consider the following models: SD2200D - Reported to be one of the deepest machines Minelab has made. Apparently the extra depth is due to the detector power supply being unregulated and the full voltage from the battery is available to the coil. Are Lithium battery packs, either commercial or home made, adaptable to this machine? On an unregulated machine I would think that a lithium battery would be preferred. At the same time I read that using mono coils on this detector is not practical because they generate too much ground noise and to use DD coils instead. A DD coil cuts the width of the coil in half with an associated loss of depth so I am confused how this machine can be deep when only using DD coils unless very large DD coils are recommended. I would like to limit max coil size to between 15-18" round. I would prefer to limit cost to between $600 and $900 on such an old machine in case it dies and the faulty component is no longer available. I have the skills to troubleshoot to the component level and make repairs on older "through hole" technology PCB's as long as the components are marked and available. What is the best coil for depth on this machine? GP3000, 3500 - I dont know much about these machines and if they would meet my requirements for depth, stability, etc. Would this be a better choice than the SD2200D? What is the best coil for depth on this machine? GPX4500, 4800, 5000 - A GPX4800 or 5000 with a NF 15" round evo mono coil (or similar) looks to be the best and the most expensive option. I might have to look for a long time to get a below market value price on one. Please advise, regards, Ceril

The discovery of the crash site is quite a story. Thanks for sharing, Ceril

The next ones will come easier, at least it did for me. Keep it up.

Interesting way to store electric energy

I'm still of the opinion that if you own a 6000 then you don't need an Axiom and also the other way around.

I was up in Spokane, WA for that 2017 Eclipse also. It got quite dark and cooled off considerably. We were in park next to a river and as soon as it started getting dark the Canadian geese' that were sunning themselves on the grass, walked to rivers edge and swam over to an island to roost for the night. Then some minutes later when the sun came out again they came back on shore and resumed sunning.

I lived in Mesquite, NV for 3 years and joined GSSN club, they have claims in Gold Basin/Lost Basin, AZ and also in Johnnie, NV. I found some nuggets in Gold&Lost Basins but it was one of the harder areas to find gold for me. I had better luck on the Pale Burro claim in the Johnnie district and the surrounding areas.

I'm 5' 10" and measured 19.25 inches.

Two different scenarios are being described here: 1. The original question was "what would happen if one was to turn a PI on without a coil connected?" In this case I would also expect that nothing would or should happen because there is no load (coil) and there should be no current flow. 2. What would happen when "hot swapping a coil" or better said swapping a coil when the detector is turned on. In this case the load (coil) is being disconnected and/or connected with the detector on and hopefully the detector is designed to withstand this but I would consider this risky with any piece of electronic gear that has an external load connected with a cable or wire.

I have refurbished 80's vintage high end audio amplifiers by replacing ALL the electrolytic capacitors and they will work brilliantly for another 20 to 30 years. Electrolytic caps age, leak, swell and degrade over time.

Thanks for the suggestions but I have found all my gold in dry and mostly comfortable conditions and prefer it this way. I could make an exception if I was missing a significant amount of gold by choosing to hunt only dry ground but it appears from most comments that dry ground provides the best overall metal detector performance for both VLF and sensitive PI like the 6K. Prospecting is a recreational hobby for me that lets me enjoy the outdoors at the same time. I wouldn't plan a camping trip or a day at the beach if it is forecast to be wet or windy and it's the same for me regarding prospecting.

Now I am a bit confused, there is JP's very detailed technical explanation of how "conductive ground" can negatively affect detector performance and at the same time there are (non-technical) observations in the field that support the opposite result.

Is this because of the mechanics of water erosion removing overburden or is there a technical explanation?

Thanks Ron, My real question is this: I don't like to metal detect for gold during or after it rains in the desert for a number of reasons but mainly I don't like to dig and recover targets in wet or damp soil and I don't like to walk around with muck on my boots. I am retired so I can choose when to go prospecting based on if I like the weather or not. So I just want confirmation that some wet or damp soils can increase ground noise, requires lowering of the gain and results in reduced depth and performance. From your response it appears that you confirm this to be the case and this will be yet another reason for me to plan my prospecting trips so as to avoid wet or damp soil when I can.

So based on this information, am I correct to think that using the 6000 (with a mono coil) in wet or damp soil, from lets say a recent rain event in the deserts of the western US, would hinder the performance of the detector and it would be best to wait some days for the soil to dry out again?

That was plenty technical for me, Thank you. Maybe even more reason for me to wait for the NF 16x10 coil to be released since the NF 12x7 is inherently quieter than the stock 11 inch, unless that is only because it is smaller (less sq inches) and sees less ground. Regards, Ceril

Can you please give technical explanation of "conductive signal"? Is that a ground condition?

Thanks for the feedback. Finding a 0.023 gram nugget, at around 1 to 1.5" deep, with the NF 12x7 is small enough for me and I have no need or desire to find anything smaller than that. If one didnt already own the 12x7 then the 10x5 might be a consideration but for me there is no need to own both.

Thanks for all the feedback guys. I spoke to two of my fellow prospector friends, (Chet and Art) who both own the GPX17 coil, regarding pros/cons of this coil. Based on their inputs as well as all of yours, I have decided to wait on purchasing a larger coil for the following (personal) reasons. One, I really like the performance and stability of the NF 12x7 mono coil on the 6000. It has been my primary coil since the day I put it on at the beginning of last year. Most of the time, I run it with gain of Manual 8 to 10, in normal or difficult, with the threshold volume turned down to where it is just audible using head phones. The NF coil appears to stabilize the chatty threshold inherent of the 6000 (yes, my 6k also has the audio/emi fix), especially when set to high gain. With this setup I investigate any slight threshold change and if repeatable then I dig. I found my personal best nugget of 19.6 grams, around 14 inches deep, a few months ago with this setup as well as a 0.023 gram nugget for my smallest. The NF coil has really boosted the confidence in my ability to find gold as long as I do my part. The elliptical shape allows me to get into spots that the 11 inch round coil wont and that is another significant advantage. Anyway I guess I am sorta hooked on NF coils performance and quality so I will see if the NF 16x10 mono will be released this year and if it has similar performance characteristics as the 12x7. Two, the Coiltek 14x9 option is too close in size to the NF 12x7 (imo) so just the simple math tells me that there is not enough to be gained regarding depth and coverage.