CZ70 Positive Groundbalance vs Sens 6 ?

I found this post on a CZ Tips page, and although he doesn't state the benefit of using a positive GB, I assume it's increased depth.

I wonder if using a positive GB will add falsing, and if so, if you'd achieve the same depth increase as using a sens of 6 (assuming you have a CZ70 that falses when set above 4) ?

I've also been told (although the manual doesn't indicate this) that it's best to set your sens on 10 when doing the bobbing method of GB. I kind of wonder if you set it on 10 when groundbalancing if it'll false less when readjusting to a sens of 6 afterwards?

Here's the post on using positive GB:

CZ Tips Page:

"Positive Ground Balance When running positive, the threshhold increases very slightly as the coil approaches the ground. After tuning the GB to obtain no change in threshhold while bobbing the coil, you turn the GB knob on the 7a/7a Pro counterclockwise (toward 1) to achieve a very slight threshhold when the coil approaches the ground. ... Hope this helps. Ron (WV) Posted on the Fisher Forum July 9, 1999 "

I'm taking the CZ70 to an old park tomorrow to play around with these settings (and hopefully find some old coins), but was just curious if anyone had any advice.

Thanks and HH,
Brian

Brian,
You will gain a very slight amount of depth capabilities.....at the forfeiture of proper ID on deep targets. Yes, a trade-off.

Performing the bobbing method w/Sens on '10' provides the most response. Any subsequent lowering of Sens thereafter is not a problem..... and usually will stabilize the unit even further.

Thanks Tom.

The park I'm going to tomorrow is the only place I've ever hunted that I've been able to max the sensitivity on threshold settings on both my C$ and my F70, so I suspect the CZ70 should perform very well here, and may well run well with the sens at 6 to get those extra deep coins.

Tom I tried to set the sensitivity at 6 at the site I hunted this afternoon, and although it was better then the site I previously tried 6 at, it was still falsing a bit more then I'd like. It was tolerable, but it reminds me of my F70 :-)

Although I didn't make any stellar numismatic finds, I did dig the deepest coin I believe I've yet to dig. I got a signal that bounced between high coin, penny and relic, with a zip or two of iron thrown in for good measure, and it read 8" deep. I decided to see what it was, and at an honest Abe 8"+ was a 1935 wheatie, and there were iron blood spots in the soil. I also got a 6" 1952 nickel that bounced between relic and foil, but sounded good and not far from there a 1955 wheatie at 6". Nothing to brag about, but for a park pounded with Explorers I felt good about the finds.

Apparently the City of Oakland in it's infinite wisdom is saving money by not watering their parks, and the ground was like chipping away at cement. I believe you loose depth with this type of ground. Once we get some rain, I'll hit this park again and see if I can get a little better depth and find some better targets. I've pulled 6" deep Barber dimes at this park before with my F70, so it has the potential to produce good targets (I'd be in heaven if they ever scrapped the grass!).

HH,
Brian

Brian,

It's a fight between wet dirt.....which activates minerals (a bad thing)...... but wet dirt can also 'conduct' better....giving better depth......AND....... wet dirt will 'swell' the dirt. Dehydrated dirt 'contracts/shrinks' ....making targets expose to lessor depths. . . . a MAJOR 'plus'.
Certain minerals in dirt can generate EM inhibitors when dry...... and other minerals can also hurt performance..... but only when wet. You MUST figure out how YOUR area responds.
Glad to hear about your 8+" higher conductor coin. Your soil does not sound like it's TOO severe.