My first Racer silver was a 1909 Barber dime, and all I have found since have been '51 and '59 Roosevelt dimes. I need to get into more older sites, and I hope to find some in April. I know I will be in some old-coin [size=small](and trade token and artifact and etc., etc.)[/size] potential ghost towns and such in mid-May when we have a casual, informal, "Welcome to Hunt" outing based out of a town on the Utah/Nevada border. I have my hopes up for more Barbers and Seated Liberties, if good fortune comes my way and I put my Racer coils over the targets.
Now, to the topic of "overload" and what it is.
To some people, the term "overload" means a condition where there is too much EMI present and the detector is unstable. So far, my FORS and Racers have been quite stable, unless I am very close to some high-power sources like a sub-station or overhead transformers, etc. That said, I haven't been in any environment that causes me to walk away because I could easily deal with it with a very modest reduction in Gain/Sensitivity.
Then we have the "overload" audio or "saturated" audio response that can occur. Again, I don't have a problem with any "in-the-air" "saturated audio" response with my initial Racer, using all four search coils at any Gain setting, or with a brand new Racer my friend got on Friday and assembled on Saturday. He has a heavy, busy work load out-of-town [size=small](actually out-of-state)[/size] from last week through at least through the month of April and has his White's M6 and Nokta FORS CoRe with him, so I am using the brand new Racer and coils he got along with my Racer and coils to do some more testing [size=small](and hunting, of course)[/size].
After reading this thread's post and comments, I went out and used 2 Racers, early version and new production run, 2-small DD coils, 2-5½X10 DD coils, 2-7X11 DD coils and 1-large 13X15 DD coil.
I used both 2-Tone and 3-Tone modes.
ID Filter was left at '10' and Gain was checked at the default setting of '70', then increased to '85' where I usually hunt, then up to '95' and '99.' I then reduced the Gain to '65' and then to '50.'
I checked everything over some nasty black asphalt in our parking lot and, depending upon the search coil used, the Ground Balanced Ground Phase was between '79.[size=small]40[/size]' and '81.[size=small]60[/size]' with a Magnetic Mineral read-out on the 'pie graph' of '7' filled in pieces.
Waving the detector around in the air, with a Pacific Power substation for our entire town just a half-block away, I couldn't get any "overload" or "saturated audio" response at all. Calm and quiet.
Could I get a "saturated audio" response? Yes, and here's when:
If the Gain was reasonably high, AND if I briskly bobbed the search coils [size=small](any of them)[/size] from almost touching the asphalt up to about 1" to 2", I could often get a 1-time space-gun sounding audio. It was not continuous, just one short little saturated audio response, very brief. Kind of part of the overload/saturated audio, not a repeating sound.
Why did it happen? Really nasty bad ground with a high Ground Phase and an intense Magnetic Mineralization Indication read-out. ... See Page 21, and then remember that 'Saturation' occurs when a target is too close to the search coil or if the target is too large. A lot of intense mineralized ground, in this case the high-responding black asphalt, was large enough and close enough to the coil to saturate the EMF. That saturation of the EMF, or you could call it warping the field or overloading the field, is what caused the very brief, partial, 'saturated' audio.
Placing a couple of coins on the asphalt and sweeping over them in a 'normal' fashion and keeping the search coil level with the ground throughout the sweep produced typical, average good target hits w/o overload .. as long as I maintained a proper coil-to-target distance.
To double check I took all the coils and detectors over to the grassy lawn. Did an automated Ground Balance in a couple of spots and the Ground Phase ranged from '75' to '79' and the Magnetic Mineralization Indicator only had '3' to '5' of the 'pie segments' lit. I could do the same brisk bobbing of the coils, or place them right on the ground and abruptly lift them away [size=small](as I did on the asphalt parking lot)[/size] and never got an 'overload" audio, even at the highest Gain settings.
So, I can only say that using one Racer for almost two months now, and comparing it with a fresh production Racer, it seems that some of the issues a few people might have with it are that they did run too much gain, and I wouldn't doubt that a few might forget to check the Ground Balance, and no doubt some [size=small](a few perhaps)[/size] could use an improper sweep technique with more of a pendulum arc to it, and that can cause a false response when quickly brought close-to and then away-from the ground, especially if it is a very mineralized chuck of dirt.
Is there a detector problem? I don't think so.
Is there a coil issue? We'll, that is possible, but I am not seeing it with the 7 Racer coils I have and am evaluating, on 2 Racers, so I don't think it's a real issue.
On the bright side, the Nokta and Makro Detector folks are, like they have been, on top of any issues that seem to be showing up and are replacing some coils. I just hope people with a Racer will double check their surrounding areas and coil presentation close to the ground to make sure that's not the cause.
One more reminder. Most manufacturers have a 'preset' marker on their detectors or give us an indication of a starting point for a Gain/Sensitivity setting and let us know that we can increase the gain in some circumstances and with some caution that a setting that is too high can cause people problems, like more EMI, and EMI is, essentially an "overloading" or "saturation" of our EMF. Remember to read about Gain on, I believe, Page 7 of the Owner's Manual as well as Page 16.
Also read the comments by Southwind as he is comparing his Racer to his E-Trac and Deus, and is only using the Racer at the 'default' [size=small](aka preset suggestion)[/size] Gain of '70.' I usually have the Racer's set at '85' gain in 2-Tone and 3-Tone mode, and most of the places I have hunted so far in Oregon, Idaho, Washington and Utah have not been mellow ground. Most have had Ground Phase readings of at least '76' and up to '86' and the MMI has been as low a '3' segments lit up, but up to '7' segments as well.
Okay, off to go hunting and I'll check in this evening.
Monte
