Welcome! Log In Create A New Profile

Advanced

Just to touch on a couple of points.

December 05, 2018 02:21AM avatar
Quote
GA1dad
Quote
Monte
Just get about working a site, using a slow-and-methodical sweep speed, pausing only long enough to isolate ...

Now that made a light come on. So swing speed should be slow with the Cibola?
Yes, with most Tesoro's and other 2-Filter, aka Double-Derivative, circuitry designs, especially in more mineralized conditions. Black sand, pea gravel. a rock-filled parking lot or other location, etc., etc. A fast sweep speed will swamp the circuitry with too much ground signal to process and not allow a target signal to pass. I also encourage a slow and methodical sweep with 3-Filter type circuitry designs, such as the White's MXT series and the current MX-Sport and MX-7 and some from other makers of multi-derivative circuitry (more than the so-called 2-Filter designs), but those designs can allow a faster sweep speed with less performance impairment than models like the Tesoro's.


Quote
GA1dad
Quote
Monte
It is a simple matter to address, however, as all the user needs to do if find the most mineralized ground in the areas you generally hunt, then be ready with a small screw driver and open the Cibola to locate the GB trimmer, then very carefully tweak the internal GB in the All Metal mode so that it is just very slightly negative in the All Metal mode with a Tesoro. Double-check the GB setting in the Discriminate mode to make sure it isn't set too negatively.

Naturally I have no clue what kind of 'Depth' you hoped for as you didn't indicate an expectation.

In response to both of the above quotes. I took a few minutes this afternoon and tweaked the GB. The adjustment was about the thickness of a dime to the negative side in order to get a nice neutral GB, but man what a difference it made in the machines performance and my optimism for it. Over the next couple of days I will double check GB at a couple of close by parks. My "depth hopes" were that it would pickup the 6 inch deep Mercury dime in my test garden, while discriminated up above tabs. Again, this is just what I optimistically hoped for. Originally it would not even crack/pop a little bit. After the GB adjustment it hits the 6" dime fairly consistently. Hoping maybe in a real world hunt with coins that have been in the ground for decades, it will hit them regularly.
Some makes and models on the market, even some that are rather expensive, do not have a good, functional GB associated with the motion-based Discriminate mode. It's just how the circuitry was designed. Having a 'proper' and 'functional' Ground Balance can make a lot of difference in a detector's overall performance. Glad to hear you took care of that issue with the Cibola.thumbs up

Now, let's look at the tough challenge you decided on to try and hit on a 6" sliver Mercury Dime. Consider these things:

1.. There isn't going to be any perceived 'halo effect' from a non-ferrous target. Even a ferrous object might have some deterioration over a long time that, possibly, might have an influence on the EMF IF it is a sufficient change in conditions AND if the ground is well saturated by the time the detector is worked over a spot.

2.. Way back in the late '60s I read a report on coin deterioration and it said a silver coin might reach its maximum amount of surface decay at the end of one year, and it would still need to be in a wet, saturated environment to create even an insignificant change in the target's detectability. Beyond one year there would be no difference.

3..If you were hunting with the Discrimination set at the lowest adjustment point to just barely reject an iron nail, then you're going to make it easier on the detector's signal processing because there will be less rejection or negative influence by the ground signal and iron signal and that will make it easier for the detector's design to process and filter the rejected ground and ferrous target signal and be able to recover and respond to the small-sized silver Dime at 6".

But trying to find a small silver Dime when the Discrimination level is set higher, such as quite high so as to reject a common 'Tab' or even a little higher creates a tough challenge.sad smiley Now the detector has a higher rejection setting and that shift will mean targets, such as the ground signal and an iron nail signal (or other ferrous debris) will drive the response even farther negative from the new 'Tab' Disc. setting and that will require more time and effort for the circuitry to try and process that very bold rejection signal and then recover to be able to respond to the 6" silver Dime.

Having the Ground Balance trimmer set way too positive was also throwing the ground signal way off and that's why you noticed poorer detection depth. Adjusting for a 'proper' and more efficient Ground Balance helped the detector's performance, and just the same, a reduction in the Discrimination or rejection level can also improve the detector's field performance.

I can't begin to tell you how many times, through many, many years of hunting with others, I have hunted behind someone or crossed their detecting route and found a keeper they had missed. They would usually be surprised that I found a good target that they had missed and would mumble something along the lines of "How did that happen!?!" I would discuss things I had observed with them and ask a question or two to show how things like that can happen.

I began with the statement that ALL of us are going to miss a good target unless we thoroughly cover our search path. That means keeping the search coil at a fairly uniform coil-to-ground relationship and not uplifting the coil at the left and right sides of our sweep. That's best handled by NOT trying to make a long, lengthy sweep but confine the side-to-side sweep to about 24"-30" and in a wide-open and uncluttered site possibly 36"-40". Not a 5 foot to 6 foot wide sweep.

Also, the very important need to Overlap the prior sweep path. Not just part of the sweep, and not only some of the side-to-side coverage, but to overlap at least 50% of the entire last sweep route. For best efficiency I try to overlap 50% to 75% of a former sweep twice, once coming from one side and then again sweeping from the other side. I know that sounds very tiring and makes it take a lot more time to cover a bigger area, but it ensures that the portion of the area did I search has been done with a more effective technique so as to most likely NOT leave good targets behind.

I learned way back in the earlier days of using a good TR and TR-Disc. detector that I could gain the best success by using a slow and methodical sweep speed and search coil presentation as I covered any place I hunted, especially those that had a greater amount of unwanted junk discards. As the years and decades progressed we have seen some improvement in detector design to incorporate Ground Balanced All Metal modes and ground compensating motion-based Discriminate modes. Lighter weight and better balanced detectors. New and sometimes helpful features such as visual Target ID or audio Tone ID.

However, with all the added adjustments and other features a few things have remained unchanged:

Lost desired objects are still out there.

Still located in various orientations and in a range of varying ground mineral environments.

Often have more modern trash discarded close to them to deal with than ten, twenty, thirty or more years ago.

Metal detector circuitry still has to process the ground mineral signal as well as the Discrimination or rejected signal.

So with these unchanged conditions, we still need to make use of the most effective search coil presentation, and that means to cover an area with a very ample amount of overlapping, and do so in a slow-and-methodical sweep to allow the device to process all the good and bad signals.

And in some ways most of our modern detector models, since the coming of VLF-Disc., also known ad GB-Disc., GEB-Disc., or more commonly referred to today as just Discrimination, that we have moved on to since 1978 have had to deal with more performance challenges than we used to back in the good old days of using a good TR-Discriminator.

A prime example is the ability of a modern detector to cleanly reject a crimp-on Bottle Cap or a lot of rusty tin shards at an old site. Most of today's detectors struggle with Bottle Caps and some other similar trash due to the motion-based circuitry's challenge to deal with both ferrous trash and non-ferrous trash as well as the ground mineral signal.

So I would point out that we all are going to miss good targets and I included myself in that group. It happens. But I try to use the best search techniques to miss as few as possible. And then I asked them a question about their Discrimination setting and if they are using a Notch Disc. model with active settings. As I explained, using too much Discrimination makes it more difficult for the detector to process the combined ground and target signal and pass along a desired target response.

In over five decades of very avid detecting, I would guess that in evaluating new detector designs or trying to hunt a site and use a Notch Discriminate set-up, I might have totaled between 2 and 3 hours .... total. A blend of intentionally hunting with Notch Disc. and spending time to evaluate a new model's performance using Notch Disc., that easily covers my total field-time.

Why? Because I do not like to use more Discrimination than the absolute minimum I can tolerate, and usually that is no more than Iron Nail rejection, especially in a tough iron contaminated site. The problem with using modern detectors that incorporate an adjustment(s) to reject one or more segments of conductivity above the primary Disc. setting is that some good targets with a conductivity at the fringe edge at either side of the Notch Disc. section can be missed, especially if the coil sweep is too fast to not allow processing of the rejected signal 'range' to permit a potentially findable target from passing after the rejected signals are filtered.

Therefore I find things others have missed simply because they either did not put the center-axis of the search coil field over them by not overlapping ... by sweeping too quickly to allow the circuitry to process good and bad signals efficiently ... or because they used too much Discrimination which also made it more difficult for the device's circuitry design to handle the adjusted challenge.

Just some thoughts. I hope you have some detectable weather and can get out and learn the Cibola well, and I encourage you to reduce the Discriminate level as much as possible.

Monte

"Your EYES ... the only 100% accurate form of Discrimination!"

Stinkwater Wells Trading Post
Metal Detector Evaluations and Product Reviews
monte@ahrps.org ... or ... monte@stinkwaterwells.com
503-481-8147
Fisher: 1, Nokta-Makro: 3, Teknetics: 1, Tesoro: 2, White's: 2
Killer B's 'Hornet' and White's 'Pro Star'
Note: Detectors are listed alphabetically by Brand. Models are chosen based on search site conditions.
*** All working well today to make memories for tomorrow. ***
Subject Author Views Posted

New to me Cibola

GA1dad 327 December 03, 2018 08:07PM

Re: New to me Cibola

GA1dad 198 December 06, 2018 06:39PM

Getting out with your Tesoro Cibola.

Monte 217 December 07, 2018 02:21PM

Adapting to your Cibola, and adabting your Cibola to the ground mineral environment.

Monte 264 December 04, 2018 07:50AM

Re: Adapting to your Cibola, and adabting your Cibola to the ground mineral environment.

GA1dad 244 December 04, 2018 03:34PM

Re: Adapting to your Cibola, and adabting your Cibola to the ground mineral environment.

Druid 182 December 05, 2018 02:11PM

Re: Adapting to your Cibola, and adabting your Cibola to the ground mineral environment.

GA1dad 206 December 05, 2018 08:15PM

Re: Adapting to your Cibola, and adabting your Cibola to the ground mineral environment.

Druid 197 December 06, 2018 03:26PM

Tesoro's and a Ground Balance control and Iron Audio ID.

Monte 226 December 07, 2018 02:52PM

Just to touch on a couple of points.

Monte 208 December 05, 2018 02:21AM

Re: Just to touch on a couple of points.

GA1dad 219 December 05, 2018 08:25PM



Sorry, only registered users may post in this forum.

Click here to login

Online Users

Guests: 19
Record Number of Users: 13 on January 18, 2018
Record Number of Guests: 302 on March 10, 2018