correlate and ground tracking speed question

[pointer80]

Hey all, just wondering on a couple of v3 settings. First one is correlate. What advantage does running correlate have over reguluar best data? Also what situation would you use correlate. Another question is about ground tracking speed. The stock setting is 25. It seems some people say thats to high. Whats everyones opinion on this in low minerilized ground. I know it says in the manual that to fast ground tracking is not good. What would be a good ground tracking speed setting? Thanks all. pointer80

 

[The Beep Goes On]

When using Correlate, you need to look at Span and Wrap as well and set them up per your conditions. A lot of folks are using LockTrack in certain situations and are having good luck with it. Although it can be time-consuming sometimes you have to try different settings until you find what works for you. Your best resource would probably be fellow hunters in your area.

White's Spectra V3 Manual - Page 37
Correlate (ON/OFF, "OFF") - Measures the targets differences between different primary frequencies and calculates if those differences likely indicate a valued target signal or trash metal.

White's Spectra V3 Manual - Page 38
Span (0 to 189, OFF, "30") - Adjust how different targets can be at the different frequencies and still be considered a likely valued target signal or trash metal.
- Higher number settings allow greater differences between a target at the different frequencies and still be considered a good or valued target signal.
- Lower number settings dictate less difference between the target at the different frequencies is require to be considered a good or valued target
as opposed to a trash metal.
- Ideal span limit varies with the ground and target corrosion conditions. Typically a lesser span limit is better suited to lower ground mineralization and/or lesser target corrosion factors. A higher span limit is better suited to higher ground mineralization and higher target corrosion
factors.
- Primarily developed for rejecting difficult iron, Correlate has an advantage over Best Data in difficult ground and target corrosion applications.

White's Spectra V3 Manual - Page 38
Wrap (OFF, -95 to -90, "-90") - When searching in the difficult ground and target corrosion conditions Correlate was developed to address, it is typical for high range
target signals (Quarter through Silver Dollar) to exceed the top end of the scale (+95) at one or more of the primary operating frequencies. VDI range from -95-+95 is circular (phase) so targets that exceed +95 re-appear at the <-> end of the scale -90s.
- Correlate normally perceives -90s indications combined with +90s indications as hugely uncorrelated (span the entire scale) so dictates such a target as a trash metal.
- Wrap limit allows correlate to disregard normal correlation methods (sequential or linear) and consider any -90s range signals that also have one or more +90s range target measurements, as within reasonable correlate parameters. In other words a +95 combined with a -95 =
one digit off (close correlation) rather than when Wrap is OFF = full scale (no reasonable correlation).
- By adjusting Wrap Limit, Correlate becomes more effective, indicating difficult targets in difficult ground as good or valued target signals as opposed to immediately dictating such signals as trash metal. Because in difficult ground and corrosion conditions the target signal at one or more frequency often wraps around to the <-> end of the scale, wrap limit effectively captures these target signals as worthy of interest.

 

[Rob (IL)]

The theory behind correlate is that iron will respond with different phase angles for the different frequencies whereas coins and such will give the correct response across the frequency ranges. So, it is one way to discriminate out iron. The drawback is that potentially you lose depth because the ground affects how the targets come in so they will appear to have the phase difference like iron might and get discriminated out. But, EMI noise would theoretically have an unpredictable response across the frequencies and might be one way to remove EMI too. So, for those that don't want to hunt the deep targets might get an advantage for skipping over the iron targets using correlate. But for those that want deeper, I don't think correlate would be a good option.[attachment 161243 Reading.gif] Rob

 

[jbow]

I'd suggest that you experiment with correlate the next time you are in a place with iron. Find an iffy target and switch to correlate, then start tweaking settings. I set my tracking on 20 all the time. I set wrap at -94, I use the default setting for the span.
When I experimented with correlate I found that I could get a better hit on an iffy signal but it took some counter intuative settings. I had to set the filter on 10khz high, recovery on 95 and I had to sweep slow (usually 10khz high is best suited to a faster swing but not in this case). With those settings the hit was more consistent and the VDI was much improved over both other correlate settings and over "best data". The target was a minnie I had buried at 8". The VDI should have been 51 but in best data it consistantly read in the 90s. With the correlate settings, recovery=95, filter=10khz high and a SLOW SWING it was consistantly in the low 60s with the occasional dip into the low 50s... much better. Why? Beats me.... but it worked, however I will not just go to a site and use those settings. I use more standard settings unless the hits are iffy and the VDI numbers are off... I think then is the time start fiddling with correlate.Don't forget to also tweak recovery, filters, and different swing speeds to see what best works at the site. I would never have guessed that 10khz high and a slow swing would have worked best but I am sure that the 95 recovery had something to do with it... but still? There could be different settings that work even better but I stopped when I got it working that well.
Just don't assume that the manual is always correct. It is correct in certain situations but odd ground and minerals can change everything. This is the strength of the V3. The E-TRAC does all this automatically but since the adjustments on the V3 are manual... the more you learn the better you can adjust it and since there are so many adjustments that you can make manually I am convinced that you can bring it to a higher level of performance than any other detector at any site. IMO, the V3 can outperform any VLF detector at any and every site but the user has to put in the hours and have an understanding of all the possibilities and adjustments. Personally, I am not there yet but I am continually amazed by the new things I learn about the V3. If you make assumptions about the V3 and don't try to make it do things you don't think it can do... well, it wont do them but you, like me, may be surprised to find what it will do if you think outside the box and try different things to get a vetter VDI and tone.

J