Travelling Back In Time With F75 ( Coin Hunt )

[GB_Amateur]

Quality metal detectors have been around long enough that it isn't easy to find virgin ground, no matter what the target goal (coins, relics, nuggets, even jewelry).  As previously mentioned, I got hooked on coin collecting when I was in 1st grade thanks to the influence of my mom and two of her brothers.  I found my first coin with a metal detector the summer before my senior year in high school (1970).  After school and three years in a good job, in 1979 I sprung for a Garrett Groundhog, thinking I would use it to make a nice profit hunting coins and nuggets the way Charles Garrett and Roy Lagal described it in their books....  Then life (many other interests) got in the way.  Fast forward 36 (now 38) years when I was again bitten with the MD bug.  A lot happened in the treasure hunting world in those 36 years.  Detectors got a lot better, and the hobby (or even 'profession' for some) had blossomed.  The low hanging fruit had been picked.  There is still plenty of treasure in the ground, but most is not very close to the surface and/or severely masked by junk metal, meaning it's going to take new equipment and techniques and/or a disproportionate amount of digging to find the good stuff.  But as always, there are exceptions.

I mentioned in a recent thread last week that I had stumbled upon a lot where an old home had recently been razed, and it appears that the city now owns it with the intent of appending the land to an adjacent park.  It's like stepping back in time -- a time when the detectors were few and primitive.  And on my journey on this time machine I was allowed to bring along a Fisher F75!  I felt like Cinderella at the ball.

My previous post reported that in 3 1/2 hours on Independence Day I found two silver coins along with five Wheat cents, using three detectors to sample the ground.  This past Saturday I stayed the entire time with the 5 inch DD on the F75, FA (fast) process, gain of 70, zero discrimination, 4H tones.  I had twice as much time to hunt and I only stopped to get water and food which I brought along in the car.  I again dug two silver coins (dimes -- see photo below) but this time 34 coppers, NO zinc, and only two clad (dimes).  Earlier my Wheat to copper ratio was 50%.  If that held up I'd have 17 Wheaties.  I could only hope.  Arriving home and soaking them, I was amazed to see 27 reverses with Wheat stalks.  You'd have thought I spent the day on a combine in Kansas.  Four Wheats per hour.  Will I ever again experience such a high recovery rate?  To emphasize, I hunted two rectangles in those seven hours, one along the city sidewalk, about 6 ft X 60 ft.  The other was of similar area along one side of the now missing house.  I wasn't finding 'spills'.  One hole had three coppers and another had two nearly touching Memorials, but all others were single finds.

The most enlightening thing to me is the depth of the coins.  All but one (in that group of three coppers) were 4 inches or less.  The Barber dime was in the 3 1/2 --> 4 inch depth range.  The Merc was 1 inch deep!  I don't think the ground where I found the Merc had been distrurbed or reworked recently.  The sod looked typical of the area.  Is this what it was like back in the late 80's and 90's?  Many of you should remember.

I returned the next day for another 5 hours but the glass slipper had fallen off and the coach had reverted to a pumpkin.  I'll give a followup post on that hunt plus next weekend's planned return hunts.  There has to be more there, but now I've harvested the low hanging fruit and what's left appears to be seriously masked with iron nails from the missing house.

 

[strick]

Nice story.....and thanks for taking us along on the ride. It takes me a year to get 27 wheats lol

strick

[GB_Amateur]

Followup:

The initial post on this thread summarized my 2nd (7 hr) hunt in this newly exposed lot, that one following the Independence Day 3.5 hour exploratory adventure.  After 10.5 hours the total old coin haul was 4 silver coins and 32 Wheat pennies, having covered about 3/4 of the available, undisturbed area.

I returned the next day (Sunday 9 July) with high hopes, and 5 hours to spend.  I began the day with the Fisher F75 set on de (default) discrimination mode, gain~90, zero discrimination threshold using the factory 5 inch DD coil.  I planned on finishing the last 25% of undisturbed sodded ground, which was along the street next to the public sidewalk.  Things didn't start well (a Zincoln) and didn't improve.  About half to 2/3 of the way through that patch with nothing of age to show, I shifted gears and returned to the previously fertile ground.  That change didn't improve my production.  The last 1 1/2 hours I decided to use the factory stock 7 in X 11 in DD coil to see if the anticipated added depth might be the solution.  It wasn't.  Large coils gain coverage and probably (depending upon settings and ground mineralization) depth, but at the cost of increased ground mineralization and added junk targets -- in all directions (along the surface and deeper).  In the end the total coin haul was a meager 3 Zincolns (you know I'm in trouble counting those), 6 copper Memorials, and 1 Wheatie.

With a workweek to lick my wounds, but then not being able to hunt there on Saturday the 15th due to other commitments, I made another trip on Sunday, 16 July, with only 3 1/2 hours allotted.  However, in the meantime I had added a coil (how can anyone get by with just 2 coils ) -- the 6 in X 10 in Fisher concentric.  I did get to test this out on Saturday, so I wasn't going in cold.  I mostly ran at a gain of 70, and in fa (fast) process, but I did experiment some with other processes.  I decided to retrace my paths, both in the previously high producing sections as well as retesting the barren strip next to the street.  The return on investment was modest:  3 Wheaties, two of which came from the same hole and a 1991 Jefferson 5 cent piece.  Although all were in spots I don't think I had previously checked (two Wheats and the Jeffy on the fringe of sodded ground and the other Wheat on the strip adjacent to the street which I had abandoned in defeat the previous Sunday), I did find some high conductivity junk targets in the previously searched ground which I should have found earlier.

Conclusions:

It's precarious to read too much into sparse results.  However the strong contrast between those first 10.5 hours and the last 8.5 hours is sufficiently significant.  I enumerate:

1) Clearly no one had ever hunted that private lot.  35 Wheaties and 4 silver coins were easy pickin's.   I don't think I can say as much about the strip of right-of-way next to the street, which yielded just 1 Wheat.

2) I vacuumed the easy-to-detect coins pretty well those first two sessions.  I'm confident there is still some left, but most of that is either well shielded by iron junk (nails?) or deeper than I was able to get with my coil, settings, and skill level.

3) The coil choice has an impact.  The large coil wasn't very productive due to the moderate to high (depending upon location) amount of junk targets.  The small coil does very well when over a good target, even in the neighborhood of junk, but suffers from coverage issues.  The Goldilocks ("just right") compromise might be the 6x10.  How much difference concentric vs. DD matters I can't say.  Fisher does make a 5 in X 10 in DD, and a Nel/Cors aftermarket 5.5 in X 9.5 in DD is also available.  My F75 Black was a recent, well studied purchase, and I chose the Fisher F75/F70 side of First Texas over the Teknetics T2 simply because of its capability to use concentric coils as well as DD's.  (There were many other detectors in the running, too.)  So far I'm pleased with the performance of the new (concentric) coil.

4) Almost all of my finds were 4 inches or less in depth, and most of the deepest (4 to 6 in) finds were multiple good targets.  The large coil did find one lone 6 inch deep penny.  First off, this lays to rest any notion that old coins have to be deep.  Yes, in heavily searched areas there is a lot of truth to this (but don't discount junk targets masking shallow to moderate depth old coins).  In virgin ground, Midwest soils anyway, not the case.  But also this sparcity of deeper finds leaves lingering doubt regarding the difficulty of good ground coverage with small coils (the 5 in. round DD here).  There likely are more good targets available for better searching techniques (and/or coils with better coverage).  I'd be surpised if I even efficiently swept 75% of the area with the small coil.

5) The grass had not been cut in several weeks which kept the coils typically about 2 inches above the soil and in some spots more like 3 inches.  We've had a wet May, June, and July so these facts are conspiring to make my detection depth less than ideal.  On the flipside, wet ground is said to produce stronger signals.

Closing, I don't have any more pretty pictures and I feel I'm ending on a depressing note.  But the search isn't over and I've learned a ton.  Still there is a lot more to learn.  If I make any new discoveries (in loot or knowledge) I'll keep you posted.  I'm giving this location a rest (hoping the grass will be cut...) and returning to a previoulsy fruitful search location and a new one I've yet to try.  But I'll be back.

 

[Steve Herschbach]

Fabulous report - thank you!!