Possible USA Nickel Vs. Pulltab Discrimination Technique

[GB_Amateur]

On 12/7/2020 at 9:47 AM, GB_Amateur said:

I'm headed out this afternoon (after it warms up a bit -- getting rather cool here in the Midwest) and I'll try some of your ideas (especially searching in Field 1 and returning to Recovery Speed = 4).

Decided to follow up on that hunt.  Call this an excuse if you like (maybe I'll even agree) but the high temp for the day was 36F (2C) and there was a slight but noticeable wind.  I was dressed warmly except I should have worn wool socks, and my gloves, which are hunting gloves with thinsulate still leave my hands getting cold.  (It doesn't help when I take them off to secure a find.)  As every detectorists knows, any distraction hurts the chances for those deeper/quieter signals.

Search mode w/11" coil settings:  Field 1, MultiFreq, 5 tones, wide open (no disc), custom tone breaks, volumes, & pitches, Recovery Speed =4, Iron Bias F2=0, gain=24, Noise Canceled and Ground Balanced as always.

Investigation mode (in User Profile memory):  Park 2, MF, 50 tones, wide open, RS=6, F2=0, NC&GB.

I started detecting in my 'garden spot' (best producer of this site) which I've been over with the ML Eqx 800 at least twice, first time with 11" coil and followup with 6" coil.  I concentrated on an area about 6m x 9m (20' x 30') and covered it in ~1.75 hrs.  The only coin find was a Wheatie very near a large buried target (old piece of corrugated culver pipe?) and I got a good signal only after facing the large target and backing away -- toe of coil less susceptible to nearby targets.  It was no more than 4 inches deep and gave a pretty consistent 21-23 (some Wheaties and Indian Head penny zone) in Field 1.  Nearby I decided to dig a 15-16 TID signal that was moderately soft (deep?) which turned out to be a junk/toy child's ring at ~5 inch depth.

After covering that area I continued for about 30 minutes in another area of the garden spot.  I got an odd signal which left-right (or right-left, don't remember the order) was reading VDI of 18,22.  It was next to rocks so I wasn't able to get a good 90 degree angle of attack confirmation but you know the drill:  "when in doubt..."  Another early Wheatie, and also in the 4 inch depth range.  I may well have been over this target previously and decided it was a (not worth digging) Zincoln, but also in Park 1 it might have signaled differently (I didn't check that before recovery...).

The last 45 minutes I went to a virgin spot in an area I've recently been working.  I got a shallow Jefferson nickel (1956-D) very close to a picnic table in a region with (not surprisingly) oodles of pulltab zone hits.  That was my last good target of the day.  Somewhere along the line I also dug 2 Zincolns and one copper Memorial cent.  I ended up only digging four pulltabs (one complete rivetless and three broken off beavertails) plus 3 nails (one of which was square).   Throw in a piece of aluminum wire and a rusty crowncap and that was about it for trash in the 3 hour hunt.

I'm just getting my teeth into Field 1 and with the distraction of the cold I was not doing justice listening for the quietest signals, although even under perfect conditions it's going to take me time to figure that out.  Park 2 for investigation mode was not very satisfactory (wilder than normal VDI's among other things) so I'm going back to Field 2 for that task on my next hunt.  I have a lot more confidence in Field 2 as a verification setting (see initial post of this thread).

One last note, even with Threshold set to zero (the minimum) there was still a background hum/buzz, presumably from the proprietary transmitter/receiver system.  I need to try plugging the headphones directly into the control module (via 1/4" female to 3.5 mm male) to see if that goes away.  More later.

[GB_Amateur]

One more followup on my experiences using Raphis's suggestions.

I've been on four hunts since trying out Raphis's settings and ideas, total of 12 hours.  The second hunt was to an area that had produced some Wheaties, a silver nickel ('Warnick') and a Buffie plus a 1920's swimming basket tag plus some other old relics/artefacts.  One strip along the paved walking path I had not searched (covid-19 distancing being one reason) so I started there but after maybe 1.5 hours (half of the hunt) I switched to previously hunted ground.  The unsearched strip was unfortunately backfilled recently (in old coin timeframe; found a copper Memorial at > 7" depth).  The rest of the day wasn't any more productive -- the only day of the four that didn't produce Wheaties.

Hunts #3 and #4 were mostly an area I had hunted previously although not thorougly (more below).  But I also spent about an hour in a previously unhunted (by me) side path to a box canyon shallow waterway.  That only produced two copper Memorials, one in the frigid water about 7" deep and the other in a spillway off of a ledge, in the 6"-7" range.  Fighting among the rocks (prior to and during digging) wasn't very encouraging.

The rest of those last two days was in an area that had previously produced old coins -- an Indian Head penny and a Mercury dime among them.  A (modest) total of four Wheaties was the old coin result for these two days.  One of these (along with a copper Memorial) were shallow and strong enough that I concluded I hadn't gotten a coil over it in my previous efforts.  The other three Wheaties, though, were likely ones I passed over due to their far-from-perfect signals.  One in particular was especially problematic and masked by both a rusty crown cap (only the main flat disk part remained) and a pulltab.  Third target from that hole was the charm, and about 6" depth.  Another Wheat was recovered from a depth of 8" to 9", as deep of a coin as I've ever found (if 9" it is my deepest).

I'm still not hearing/noticing the faintest (fading in and out of detectable range) signals.  That will come, I hope.  But in the meantime I'm investigating the super-iffy signals that often turn out to be vertical (err, not horizontal) nails/wire.  I can't really describe how these sound, maybe because I just don't understand them well enough.  However, Raphis's posts have me listening more carefully than ever before and that, IMO, is what is leading to these difficult, sometimes masked old coins.

The one thing I'm experimenting with is comparing Field 1 sounds&VDI's to Park 1 sounds&VDI's after finding a target.  I still use Field 2, 50 tones, Recovery Speed = 6 for investigating the nickel zone (12-13) signals which seem to be pretty consistent between Park 1 and Field 1.  Oh, and another thing I'm experimenting with (target investigation only) is Gold 1 with its VCO signal and apparent stronger signal (for a fixed depth).  Just starting to look at that.

Since initiating this thread I've seen comments from other posters on other threads about finding nickels at 10-11 and 14-15 on the Eqx VDI scale.  Also there has been mention of Indian Heads coming in with VDI of 18 and 19.  All of these are in my "aluminum" reject zones (by ear, not by notching).  Why?  In 265 hours in this particular muni park this year I've dug 1299 pulltabs of which >90% came in 12-13.  If I recover targets farther outside that range, Imagine how much of my time I'll be digging aluminum trash.  Although the pulltabs are densest around picnic tables, there is hardly anywhere they aren't distributed.  All the places where people spent time they were drinking beer and sodas, too.  The previous detectorists in this park didn't clean up the pulltabs for me but rather just cherry-picked the high conductors.  😠