F75 is a great relic machine

[rob.ream258]

I've always heard that the F75 was a great relic machine but never been on grounds where that quality could shine. I've taken it to St Louis where I found a 3 ringer and my first round ball but with only 100 square foot of good hunting turf, the machine really didn't have a chance to get warmed up before I walked it back and forth twice over. Everything changed this past year getting laid off from my job and I had to take a job 100 miles away just to stay in my career field. Its a tough commute but every lunch hour I get the opportunity to hunt around a lake with over 200 years of history.

To explain my turf and how the signals sound......

Extremely old oak trees around most of the clover shaped lake with bare exposed roots extending around most of them. On the Western side of the lake has new townhomes and all that area has 1-2 feet of fill dirt - the other many sides has minimal fill dirt. All throughout the park there is enough can slaw to fill a warehouse but excluding the slaw the ground is very clean.

For once in 5 years of owning the F75 I run the machine in boost process with sensitivity at 80 throughout all my hunts....I routinely hit targets at 12 inches....

Two weeks ago I learned a valuable lesson on how the relics sound when I decided to dig a repeatable deep target that varied from 40's - 60's in all directions and 10 inches down...hit an old button. Turned out to being a Civil War era Artillery uniform button. That same week I hit another variable target bouncing from 20-40......hhmmmm...... being that it was 12 inches down it had to be old. Turned out to be a round ball and since it was only 1 tree over from the button I'm guessing that it's also civil war era.

Last week I came across another 40-60 and remembering the previous week I got excited to see what would come out of the ground. Another button.....this time a WW1 button 1909-1920. Another great relic.

And then today........20-40 a couple trees over and another round ball.....

For the first time I am on old dirt and able to use the power of the F75....

Question: Does anyone know why roots of the old oak trees ping high tones (80's - 90's repeatable in several directions) but disappear once all the dirt is dug out?? (yes - I checked the dirt also) I pack the dirt back in the hole and the signal is still gone............why???

 

[jim tn]

Isn't this a grand, exciting and fulfilling hobby? Some really nice finds. Your 75 is smoking. HH jim tn

 

[vlad]

Roots have a saturation of mineral including iron-but there must be something peculiar at times to certain ones [size, configuration.]
There are cases where sometimes the root mass may be wrapped in wire to hold it together-I wonder if all of it is
removed? Could there be a soil clump that responds falsely-until broken up? Do you also get this signal in p.p., or stat; often iron gone to mineral will respond good in disc.
but the detector will null in pin point/stat.
(are you careful on the ground balance-I have had rocks read metal that were different from surrounding matrix)

 

[dfmike]

Super nice looking button.

 

[rob.ream258]

yep - but these tones are high and not iron - repeatable - in pinpoint and swinging. Huge roots from 200+ year old oak trees - these things are massive - haven't measured them but I'd guess a 20 ft circumference. This happens all the time - had it happen again today on root bigger around than a coffee can. Thing is, this only happens on roots that are visible on the surface.

Running the machine in BP sensitivity 80 disc at 10 and only dig the iron that jumps out of that range......ground balanced every day but always in the range of 50 - 52 - doesn't change because we haven't had any rain...

 

[James/Washington]

I bet those high, disappearing signals are what is left of rusty iron that gives a high signal but the rust falls apart when dug and blends in with the color of the soil so you actually do not have or see an object. Many years ago the tree roots trapped small iron and over the years the iron has rusted until nothing is left but a rust halo. Take a strong magnet next time and when that happens, run the magnet through the soil. I bet the magnet will pick up lots of rusty and small filings from the dirt. Give that a try and report back your findings. Yes, the F75 is an amazing, all around detector. The more you use it and the more hours you put on it, the better it, and you become at finding the goodies.

 

[jim tn]

I do believe you nailed it James/Texas. When that happens to me I probe/move the dirt looking for a rusty spot just to satisfy my curiosity. HH jim tn

 

[markg]

I might add one thing:
I've had the same thing happen many times over the past decade or so.
Once the dirt is removed a signal completely disappears, keep digging. The absent of dirt will sometimes cause the machine to miss read the deeper targets. Deeper is the key, if the sound soft, keep digging.
In the majority of these cases, for me, I dug down another 3-4" and started probing the hole with a pin pointer. Most of the time there was metal down deeper than the original hole.
I've dug a many targets several inches below roots, some good some not so good. It is hard work at times.

 

[JJames1610]

Something i have noticed sometimes to is, if its really wet under a root. It will give a good single to. I can go from dry dirt to wet dirt and get a signal. Just a thought.

 

[rob.ream258]

Texas James....... magnet test is a bust..... the hole free of metals... going deeper was also tried without success... we're in a drought here in this part of Florida so the ground is "Arizona dry" and is starting to become rocks...... went back to the exact same root and it still hit the high tones (80's) in the very center of the root in several different places also (real big root) .... at that depth and tone the target would definitely be silver........ too bad it's a ghost ................ haven't gone back to all the trees so this is just my preliminary observations...

Just re-read the posts......... could a real hard clump of dirt react like a hot rock until it's broken???? I really don't know since I've never hunted on this type of hard dry dirt... it's really dark soil if that matters....

An update to the finds though..... the count is up to 6 round balls from that same area. All the balls are hitting around 10 inches with a bouncing signal around 47....... even digging some of the iron grunts and getting some cool heavily rusted rings and other horse tac....