John said:
It appears that many have been shipped with a terrbly positive ground balance. Mine starts making noise about 6" from the ground. The ground around here is very mild. 6" is way too positive.
For some who I know don't know how to check the GB response, just hold the search coil about 6 inches to 8 inchers above some metal-free ground.
Press the Pinpoint touchpad and you should hear some slight audio [size=small](Threshold).[/size]
While pressing the Pinpoint touchpad, lower the search coil toward the ground and listen for any audio change.
Naturally, a lot of what we hear will depend upon the intensity of our ground mineral content, but if you have neutral or very low mineral content, there should be very little increase in the Pinpoint Threshold Audio as the coil nears the ground. If you are in moderate-to-high mineralization you might hear some audio change as the search coil gets very close to the ground, like maybe within 1" to 3".
If you start with the search coil from 6" to 8" off the ground, and quickly hear an audio INCREASE by the time the coil is lowered to maybe 5"-6" and it continues to peak as it is lowered, then the Ground Balance setting is WAY TOO POSITIVE!
My 2nd Euro-Tek Pro had a difference in GB performance between the Discriminate and Pinpoint models than the first. It was positive, but not quite as positive as the first E-T Pro. The 1st Euro-Tek Pro was way too positive and it was easy to discern when I tried accessory coils on it, as well as on the 2nd one I got. I got both with the stock 8" Concentric search coil, and I used a brand new 11" BiAxial [size=small](Double-D)[/size] and my own 5" D-D coils on both of these detectors.
I used the same assortment of test coins, to include 'V' and Buffalo nickels, an Indian Head cent, a silver dime, quarter, four Walking Liberty halves, and a silver Morgan Dollar, and I used a piece of rusty tine, an iron nail, and a pocket knife [size=small](steel)[/size]. The biggest problem was with my first Euro-Tek Pro. The Pinpoint GB was noticeable way more positive that I would ever adjust it, peaking abruptly when lowered about 2" down to about 5": or 6" off-the-ground. That was with all three search coils.
I next checked the responsiveness of the E-T P with the stock 8" coil using all the test samples, setting the Volume for about '13' to reduce the loudness of ferrous targets. I noted two things with regard to their response. The Nickel, Indian Head and Dime gave okay responses to a certain "air test" depth [size=small](distance from the center axis of the coil)[/size], but the Quarter seemed a touch less depth, and the silver Half and silver Dollar were notably 'shallower.'
I enjoy using smaller-size coils, and my 5" DD has served me well in the past on an Omega so I mounted it up to test. The Euro-Tek Pro wouldn't give a positive response on the Morgan Dollar and broke up on the Walking Liberty Half. The 11" DD coil was even worse. It was the same behavior I have seen from some Compass, Tesoro, GMT, and a few other detectors when the Ground Balance is way too positive. So, I set out to try and resolve the issue.
I sat down at a table with all my coin and iron samples as well as three baseball/softball size very mineralized rocks, opened the ETP, and noted there was only one trimmer on the front side of the circuit board. I didn't explore farther than that, just trusted it to be a GB trimmer and checked things out. First I started with the 11" DD coil because it had the worst performance. Working with the Pinpoint function, I tweaked the trimmer reduce how positive the GB setting was, and continued while also checking the response to the silver Morgan Dollar. Once I got the GB adjusted so I had a reliable response from all coins with the 11" DD coil, I checked the 5" DD and then the stock 8" Concentric. All worked fine with adequate response.
Using the mineral rock samples and the Pinpoint mode, and with all three search coils, I still had a positive GB. Not as positive as it was out-of-the-box, but more than I would ever set it if the models had an external GB control, and far more than it would balance to if it had the fast automated Ground Grab balancing like the Omega or G2. None-the-less, I left it 'workable' as it was then, put it back together, then went out hunting a lot of sites, several that I know are VERY mineralized. The ETP then worked okay with the 8" and my 5" DD, but even in the worst ground the GB was still too positive.
I sold it, but a couple of weeks later acquired another from out-of-state, brand new, and wanted to see how it compared to my first one. I ordered it with the 8" coil, which I prefer to the 11" DD, but I still had other coils to check it out with. The first thing I noticed was it worked better than the first one, responding with all three coils to all coin targets. The Pinpoint mode's GB was a little positive, still more then I would like, but it was even better than the first ETP even after I tweaked it.
The good news was that the 2nd one worked better. The bad news was that the 2nd one worked better, and that's because it hints to inconsistency in design, calibration, and check-out before being shipped. I like 'simple' but I also prefer to have ample control of important functions, and Ground Balance is one of the most important in the performance of our modern-day detectors. So, I sold that one and am satisfied with what I own and use, and also satisfied with the performance I get from an Omega, thanks in part to the automated or manual GB options.
The Fisher F19 uses the similar Volume control concept to reduce Ferrous target loudness while still hearing a full audio from non-ferrous targets, but it also has a fast-acting automated Ground balance [size=small](or manual if you choose to)[/size] and that makes a big difference. I wouldn't mind paying a little extra for a Euro-Tek Pro with only Ground Balance added. No need for back-light or other notch functions, etc., or for the too-rapid auto tuning. Just keep the ETP the way it is except add Ground Grab and it would be a great value detector with far more versatility and ability to use optional search coils and be properly balanced to the ground being hunted.
Monte
