O8K notching Issues

[*SodBuster*]

Howdy all, This is my first post to this forum since I joined,all though I have been reading the posts for the O8K and ETrac for almost a year before I joined. I have learned a wealth of information from several
detectorist from these forums. I have read everything I can find from "Monty". The experiences and wisdom we can learn from this man is something money just can't buy. Ok, on to the issue. Today for the first time I changed the coil on my wife's' Omega to a 5" DD after using the 11" DD for several weeks. It rained a while earlier this morning and it rained hard for a good 20 min. after we got there. After the rain passed through, we sat out hunting. This park was Est. in 1932,has been hit hard over the years. Loaded in junk that has accumulated decades prior to the establishment. She ground balanced after picking the sensitivity of around 50 in AT mode. Disc. setting of 15. After a short time of hunting she decided to test the notching on this detector. She notched out Iron,foil,P-tab & S.cap. From that moment on, all her targets that came under nickel,zinc & dime was pull tabs and screw caps. So it seems that everything she notched out now came into the next available target category's (No Iron or foil Came in). And yes, we understand the repercussions of using the notching and high disc. settings. This was just a test. From that moment on she really got frustrated after expecting some good finds with the 5" DD coil only to dig numerous P/tabs and screw caps. I talked her into taking a small break with me while i was trying to figure out how to fix the issue. I notched everything back in and reground balanced with a disc. setting of 15. After the short break I told her to try the settings I had adjusted it to and tell me what she thought. We moved from that area to a place close to some stairs that brought you down to a different level of the park. She did manage to start picking up some clad coins in a short span of time but i did see the still lingering frustration from now the wonder that her new detector was faulted with a notching issue. She was still digging some P-tabs & S.Caps while watching the expected Target icon of nickel, zinc and dime. I lost interest in a short time and couldn't enjoy any more hunting after the exhibition. On the way home she told me that see didn't see any difference between the 5" and 11" coil except for the lost coverage and that she wanted her 11" DD coil back on. I explained to her that the notching issue had nothing to do with what the small coil was designed to do.She understood completely but she could not see any advantage of using the small coil that still produced allot of P/tab & S.Cap digs. I was wondering if anyone else had experienced any of these notching Issues on the O8K? Aside the fact on her decision not to use the 5" coil in the dense trash area, I did see this detector change its attitude from what it used to be with the 11" DD. She knew what the trash numbers was under the old configuration and indeed didn't dig near as much trash. So possible problem with both the Notching and coil? I have no other ideals. Thanks in advance for your time.

 

[*SodBuster*]

3 things that I do need to add, (1) The Ground Balance setting was at 57, (2) Audio Tone setting was at d3 and I misspelled Monte's Name. Sorry Monte , I hope you are getting better

 

[Monte]

I'm going to go get my Omega and spare coils out of the van and work up an answer for you. I hope to post it in a few hours. Pretty certain I know what my reply would be, but I'll confirm by 'best guess" first.

Monte

 

[Monte]

*SodBuster*, I'm a little tardy but the meds kicked in and I got some much needed rest. So, now that it's close to daybreak and detecting time, let me cruise through your post and maybe ask a question or make a comment. Then I am going to address search coil types, their TID response differences, and comment on Notch Discrimination, which is a function that I have never been too thrilled with because too much discrimination = too much good-target masking. I might get done in time to work in a little hunting today if lucky. Anyway, let's see if any of this is a help.

This is my first post to this forum since I joined,all though I have been reading the posts for the O8K and ETrac for almost a year before I joined. I have learned a wealth of information from several detectorist from these forums. I have read everything I can find from "Monty". The experiences and wisdom we can learn from this man is something money just can't buy.

I am not alone when it comes to trying to help others get the enjoyment that's possible in this great sport. As for the two models mentioned, I care very little, personally, for the E-Trac which I think is still too heavy and uncomfortable, and the 'new' abrupt bend angles for the grip and reposition of the display are just not comfortable for me. Besides, I like not only 'comfort' in a light and well-balanced detector, but I also like ample manual control while maintaining simplicity. I've used every FBS Minelab model and have owned most of them. They can do what they do, but like all detectors they have drawbacks. If I were to invest in another of that series today, it would be the Safari for the simplicity with ample performance.

That said, it would also be used far less than my T2 and especially my Omega because these models, especially the always with me Omega and coils, is just near 'perfect' for the wide range of hunting that I enjoy. If you've read enough of my posts you'll know that I most often hunt with a minimum Disc. setting of '1' so that I can hear ALL metal targets, and usually I opt for the d2 audio response (to help audibly separate iron from non-iron, or I like d4 tones when I am strictly "coin hunting" in high coin count sites, such as playgrounds or around picnic areas, refreshment stands at sports fields, picnic areas at beaches and such, just the high-traffic, coin-likely sites. You also know that I enjoy using all the coils, especially the stock 10" concentric and the little 5" DD.

Ok, on to the issue. Today for the first time I changed the coil on my wife's' Omega to a 5" DD after using the 11" DD for several weeks.

So, before we go too far, let's make sure we are comfortable with the coil choice and Omega use. Has you wife used the Omega a lot? I mean to the point where she is very comfortable with all the settings and such?

Has she used the stock 10" concentric coil very much? I personally prefer the stock 10" coil for many day-to-day hunting tasks, especially when coin hunting, because a concentric coil will often/usually provide a more consistent audio response on the left-to-right and then right-to-left sweep over a target, and whey will be less bothers by coins closer to the search coil. A Double-D (also called wide-scan) coil design has its strong point, to be sure. However, with many/most DD's you'll note that they might be a bit more errant when swept fro one direction as compared from the other, and this is due to the coil configuration. Also, you will often note more inconsistent audio response or multi-hit response from shallower targets, especially with the 11' coil.

My biggest concern, when I see folks using different search coils, is if they are using them AND expecting to have identical end response from them. If so, this, too, can be a cause for concern. With some makes and models of detectors on the market you might see a little tighter TID from different coils. The differences is size and coil dynamics between the 5" round DD, the sub-10" elliptical Concentric, and the +11" BiAxial DD coils need to be tested by the detector/coil owners so that they understand these differences and are aware of how some targets might mis-report in the field. Usually it isn't a big deal, but if you rely highly on visual Target ID and VDI numbers, you need to get a good sampling of targets and do side-by-side comparisons with each coil you have using the same settings.

When i first got my omega I was eager to put the 5" DD to the test at a couple of interesting trashy sites I have nearby and I noticed that some VDI readings were just a bit different from the stock 10' Concentric coil. I knew this could happen and I simply recovered the targets that were there, An early nickel, two early wheat-backs and an 188? Indian Head cent. They were good audio 'hits' and workable VDI numbers, but I felt they were maybe slightly different from what I had noted with the stock 10" concentric coil. I later evaluated an assortment of coins in my kit so that I understood the differences I might expect between the 5", 10" and 11" coils.

Before I got some much needed sleep last night and then finishing up this morning, I used my own Omega, all three coils, and did some side-by-side comparisons here in my computer room. I simply turned the Omega 'On' with a Disc. setting of '1', left the Ground Phase at the default '82', set the Sensitivity level at '85', and used mainly the d4 audio tone response. Here are the VDI number differences I got from an assortment of targets I've found and keep in my 'kit' for demonstration purposes. This will let you see some differences between each search coil for certain coins:


Nickel 3

 

[txquest]

Excellent post Monte. Thank you for your time and info. Txquest

 

[rick (nova scotia)]

I do not use notch either, there are just too many good targets that fall into the P tab, S cap range. In fact with the exception of the largest of rings this is where most of the jewelry will be found. Now I do apologize for not remembering the exact TID # for this ring when found, but it was less than penny, somewhere around 70. So anyone notching out S caps would not have found this one.

I also prefer the stock coil. Yes I have tried the 11" DD but I do not see the depth advantage that everyone else seems to. OK maybe a tiny amount, but not a full inch on most targets.

Rick

 

[*SodBuster*]

Monte,
Thank you very much for the in-depth, detailed explaination and time involved for your help. I really appreciate it.