Report from the field on the GPX 17" monoloop coil
Life before the GPZ7000 seems so long ago, prior to the Zed I was using the GPX 5000 and had an absolute armoury of coils to put on depending on the conditions I was encountering. Out of all those coils there were 3 sizes that saw the most use, an 11 or 12 inch mono, an 18 inch round mono and the mainstay coil that did all the heavy lifting/prospecting was a 17 inch elliptical spoked coil made by Nugget Finder.
The 17” elliptical coil was so good because
it performed three roles brilliantly, it offered more depth than a 11 inch
round whilst at the same time having nigh on as good a sensitivity to the small
stuff as the 11”, but most important of all it provided excellent ground coverage.
Fast forward to present day and I am now
a lot older and unfortunately carrying a few injuries acquired along the way after
years of heavy repetitive coil usage.
Out of the box the GPX6000 comes with an 11 inch monoloop coil and a 14 inch DD, the DD allows users to work in EMI or salt environs, it is not a DD coil aimed for use in noisy ground like traditional DD coils of yesteryear - the Difficult timings of the 6000 now do that for you. The DD design is so that the detector can remove unwanted EMI signals or salt/conductive signals, as such the outright depth drops right off compared to monoloop coils so the DD coil should only be used in areas that the operator cannot work effectively with the other coils.
The supplied GPX11 mono coil is just incredible on how sensitive it is to small gold, even in really bad ground. The detector feels so natural to the hand with the 11 inch coil attached but I personally find it hard to make myself slow down because it is too light (never thought I’d find myself saying that). It is way too easy to buzz along at a quick clip because the balance of the GPX 6000 is nigh on perfect, as such because I am used to bigger coils I tend to find myself zipping along trying to get more ground coverage.
Enter the GPX17 coil, this thing is light weight for its size, that’s the first and most obvious thing about it. There is also a lot of top side real estate on the coil because it has a solid top but when you pull the skid plate off you soon see some clever design has gone into getting the weight down. It’s kind of like an upside down spoked coil. The key thing here is lightness of weight and boy it is light for such a big coil. The other thing that was immediately obvious was the sensitivity, its very close to the GPX11 coil, so not much trade off there.
Depth is as expected and definitely better than the GPX11, but to be honest depth does not interest me that much with the GPX6000, I have the GPZ7000 for that!! No what interests me is the amount of ground I can cover in a given time frame whilst patch hunting!! I can scoot along cutting huge swathes with this coil as I traverse the country looking for a new patch, and in the time I have used this coil I have put that to very good effect. Covering a lot of ground is paramount to finding new patches, but also it’s important you have a coil that will ping the tiniest of pieces because it is those points of gram nuggets that pull you up and allow you to scout around and find where the main run is.
The balance and feel of the GPX 6000 with the GPX17 coil attached is extremely good. However I found a couple of nuisances, one is because it is so long if you clip some grass at the front there will be enough pressure to pull the coil out of alignment, this is because the upper and lower shafts do not have any locating dowels so you need to get a decent amount of pressure on the locking mechanisms to prevent the twisting even then it will still twist if you hit it hard enough. Secondly because the GPX6000 is so sensitive the larger coil can be problematic if the ground has any salt or conductive component. I hit a few areas that got the salt wa-waa’s happening so have ear marked them for a return with the DD coil in salt mode.
I found using a HipStick with a GPZ7000 Velcro bungee attachment and GPZ bungee wrapped and pinned with a zip tie around the handle made for a really nicely balanced detecting experience. You can use the GPX17 free handed but eventually the detector will wear you out and punish you. The GPX6000/GPX17 detector/coil combo is all about long hours in the saddle covering as much ground as possible in a given time frame, as such you need to bungee up. Secondly I found the GPZ7000 Guide arm worked a treat attached just above the locking nut on the mid shaft, this also had the added benefit of stopping the torsional twisting of the shafts when the coil front comes into contact with grass clumps etc.
The sensitivity of this coil is superb, I have never had a detector that can, whilst at full gallop, ping a 0.05 gram piece in grass before, but with this set up I did it many many times. I have also never had so many widow nuggets which is interesting and goes to show that gold bearing country has more scattered gold laying around that I ever thought. All of those widow pieces of gold no matter how tiny could point to a patch that I have just not discovered yet, so as frustrating as they are at times, any gold is most welcome when patch hunting.
So I now have a lot of options in my prospecting arsenal, for patch hunting/coverage I put on the GPX6000 with the GPX17 coil, for deep ground hunting it’s a no brainer and go straight for the GPZ7000, for crumbing or just leisure detecting it’s back to the GPX6000 with the GPX11 coil and go and have some fun.
Jonathan Porter © 2021