By Steve Herschbach
I am a big fan of the Fisher F75 from a different perspective than most. I am a prospector and have done very well finding gold nuggets with the F75. The very powerful all metal mode combined with the simultaneous on screen target id numbers have allowed me to quickly and efficiently hunt trashy tailing piles in search of large gold nuggets. The light weight and superb balance make the F75 a pleasure to use for long hours in rough terrain. It also was my detector of choice for my one and only trip to the UK that I have done so far, and it served me well there.
I spent a month in 2013 metal detecting on Jack Wade Creek near Chicken, Alaska. I kept my great results there quiet pending a return trip there in 2014. That trip has now been made but that is another story already told in detail on my website. Now I can finally reveal the details of the 2013 expedition.
I started out early one morning with my big gun pulse induction metal detector, but got onto a tailing pile that had ferrous trash scattered down one side, and I was just not in the mood for it that morning. I went back to my truck and got out my trusty F75. I run the F75 in all metal because it has instant target response; there are no worries about recovery times in all metal. The coil picks up every variation not only in targets but in the ground allowing me to monitor what is going on at all times. Knowing what the ground is doing is important in keeping the ground balance properly adjusted for maximum results.
The key thing I like about the F75 in all metal however is that the meter always runs in discrimination mode and places a nice, large target number on screen while in all metal. The audio alerts me to a potential target, which I then analyze more carefully while watching the target numbers. All metal goes deeper than discrimination modes, so no on screen number means a very deep target beyond discrimination range. This alone makes running in all metal desired when prospecting because running in discrimination mode would miss all those extra deep signals.
In all metal I dig them until a target number shows up. Deep targets or small targets in mineralized ground will often read ferrous, so I watch the numbers and if they even once jump to non-ferrous, I dig. Only targets that give a 100% strong ferrous reading over multiple sweeps can be safely passed. Though I will throw in my caveat that no discrimination system is 100% accurate and there is always a risk of passing a good target. When in doubt, dig it out!
I do often employ pulse induction detectors and do very often just dig everything. I advocate that when time and conditions allow. The reality is this is not always practical for many reasons. Maybe it is just limited time and overwhelming amounts of junk. Better to increase the odds by using discrimination than bogging down digging 100 nails in a small area. In my case it often boils down to fatigue or flat out not being in the mood to dig junk.
So it was on this particular morning, and therefore my F75 came out and I got to work sorting through the trash working my way up the side of the tailing pile. I crested the top and got a strong reading and looked down. There was a shallow dig hole with leaves in it, obviously from some hunter there in prior years. I figured the guy had recovered a trash item and kicked it back in the hole so I cussed him quietly under my breath. I hate it when people do that!
Then the target numbers caught my eye. They were all over the place. A crumpled piece of flat steel might give numbers like that though. Still, I was curious and figured I would retrieve the trash this person left in the field. I gave the old dig hole a big scoop, and out pops a big gold nugget!!
I seem to have a talent for finding ugly gold nuggets, and this one was perhaps the ugliest I have ever found. It looked more like a rock burnt in a fire than a gold nugget when I dug it up, though the glint of gold is unmistakable. This gold however was very pale and in fact later analysis revealed it to be roughly half gold and half silver and other metals.
It is a little known fact that gold alloys tend to have very poor conductivity ratings. Gold is very conductive, and silver is a superb conductor. You would think adding silver to gold would improve the conductivity, but in fact just the opposite happens, and the conductivity lowers dramatically. Gold/silver alloys are closer to lead in conductivity than that of the pure component metals, explaining why bullets read identically to most gold nuggets.
This ugly nugget is a detectorists worst nightmare, because the 50-50 alloy mix and rock content give it a much lower conductivity reading than would be the norm. I surmise what happened is this earlier operator got a poor signal and gave a dig to get the coil closer to the target. The signal did not improve, as would be expected with most gold nuggets, so the operator decided it was trash and moved on. The rest of the hill being covered with junk no doubt contributed to this decision.
It was my insistence on investigating everything except 100% ferrous readings that made the difference. The readings on this target were not solid as one would expect from a pretty strong signal but all over the place. Most people would say that indicates a trash target but I have seen many gold nuggets do the same thing in mineralized ground. The result is I dug a shallow 2.33 ounce gold nugget that somebody else walked away from. Sadly for them one more scoop would have revealed the nugget for what it was. Hopefully this is a reminder to the reader that far too often detectorists look for excuses not to dig. How many good finds get left behind because we do not want to take that extra minute or two to dig a target?
This nugget is far from a premium find, but I have already sold it for over twice the cost of a new Fisher F75. That detector was a real money maker for me as that was far from the only gold I ever found with it.
Unfortunately I say was. I made a huge change in my life in 2013 and moved from Alaska to Reno, Nevada. The move resulted in a desire for me to weed down my detector collection. I was pretty excited to do some coin detecting in Nevada where the potential finds were much better than those possible around Anchorage, Alaska.
Almost all my detecting with the F75 had previously taken place in rural locations far from possible electrical magnetic interference. In Reno, EMI raised its ugly head. I found much to my dismay that the F75 did not like my new location, and in fact when turned on to hunt the yard at my new home I could not get it to settle down at all. No matter what I did the machine chirped and beeped and numbers flew all over the screen. Unfortunately I experienced what many urban hunters have found out – the F75 is a very sensitive high gain detector that does not get along well with electrical interference. I ended up selling my F75 in 2013 for this sole reason.
Fast forward to the fall of 2014. I am contacted by the good folks at Fisher wanting to know if I am interested in trying out a new version of the F75 they are preparing for market. I of course say sure as I am always game to go metal detecting with different units. A new F75 is sent my way along with a list of the possible improvements. One immediately gets my attention – improved resistance to electrical interference.
All the focus was on a new mode or “process”, as Fisher likes to call them. The new FA process is intended to better pull non-ferrous items out of trashy or mineralized ground. It does indeed work as advertised as I found out in an accidental situation I came across.
I went to a local park and did a simple hunt for non-ferrous targets, comparing the DE default mode to the new FA fast mode. I did not really care what I found as long as it was non-ferrous. I should note the ground here is very difficult, reading 1 on the Fe meter, the second highest reading you can obtain. Hunting in this park is very much like nugget detecting, and the best detectors get very limited depth and highly inaccurate target numbers as a result of the high mineralization.
One spot really summed it all up for me. I found three targets I could cover in a single wide swing that all read as ferrous in DE mode, but when I switched to FA mode all three switched to non-ferrous. FA mode is very fast with short, machine gun type reports in the audio. I was running in two tone mode, with ferrous giving low tones and non-ferrous high tones. In DE mode I could sweep and get three low tones in a row. Simply switch to FA mode and now there were three high tone reports in a row. This was an extremely dramatic result seen in person. In this case all three targets proved to be nothing more than aluminum targets, but they could just as well have been small hammered coins in the UK or small gold nuggets in Alaska.
I hate to oversell things and I have to note that the difference in going to FA mode is not going to be earth shaking. Most targets read the same in DE and FA modes. But FA provides a tipping point, a little push that takes targets previously ignored and lights them up. By shortening the audio response on targets it also attenuates responses to a degree and so depth and signals on the tiniest targets may be impacted. Depth however is not useful if a target is misidentified or ignored completely due to target masking from nearby objects. FA mode is another tool in the toolbox that can help produce targets in specific situations previously overlooked by others.
The new F75 also expands on the available audio options in ways many people will appreciate. These additions and the new FA mode will tend to get all the attention, but for me they pale in comparison to the new ability of the F75 to engage and disengage the new Digital Shielding Technology (DST). The version of the F75 I received had DST engaged at all times, and the difference in my ability to use the F75 at my home was as dramatic as it gets. My previous F75 was basically non-functional. My new F75 ran just fine, with only minimal EMI discernible at higher gain levels.
I noted no downside to this. Given the situation, how could there be? Other field testers however were concerned that in low EMI situations perhaps there was an edge lost by having DST engaged, and so Fisher decided to add the ability to engage or disengage the feature as desired. It does not get any better than that. Use it if you need it; leave it off if you do not.
All I know is this. What difference is there between a detector you can use and one you cannot use? All the difference in the world, and in my opinion I struck gold a second time with the F75 seeing it run with the new Digital Shielding Technology. That one feature alone means I can use the F75 in urban areas where I could not use it before, and vastly improves the reasons for my owning the detector once again. I am very confident a great many people will agree with me when they get a chance to try out the new, improved F75. Everything else in my opinion is just icing on the cake.
By Hepplewhite Explorations
We head out most weekends for a little adventure whether it be prospecting, detecting, offroading or ???
Video attached sharing some of our experiences. Thanks and looking forward to seeing some of you in the field!!!!
Will also post some cool photos later, from our last trip, found some cool old sluice boxes etc and equipment on the rivers edge.
Dennis and I took a quick trip down to Baja MX for some detecting. No problems crossing the border at Algodones and no hassles at the military checkpoints. Day 1 is really just a travel day. A lot of Baja Highway 5 is still under construction from San Felipe south. The road got washed out from a storm 2 years ago and the repairs are slow going. Day 2 we got a good start taking my Rokon and Dennis's Yamaha Fat Tire bike about 3 miles up some tricky technical ground of gravel and calcrete bedrock. From there it's another 1.5 mile hike to some of the old placer workings. These placers have been worked off and on for over 100 years so all the easy stuff has been drywashed and detected. I concentrated on 100 yards of old black schist bedrock. The nuggets originally worked down into small cracks and got filled up and over by years of weathering. All of these nuggets had to be chipped out of the bedrock no more than 3 inches deep. The bedrock is tricky because it has varying levels of mineralization and hot zones that hide the target signals. I found that by running max Sensitivity and low threshold with the Patch Locate feature I could pick out faint whispers from the background of hot ground. I picked up probably 10 or 12 nuggets the first day.
Day 3 was a lost day. I got halfway up the wash when my back tire went flat. Normally, we carry everything to fix flats, but this one had "chingered" the valve stem. I had to disconnect the rear chain drive and limp it back to camp on the front drive. I did a fair amount of walking and pushing through the steep rocky areas. Back at camp I pulled the wheel and drove 70 miles back to San Felipe for repairs. 20 minutes work and $10.00 got it going again. My day was lost so I drank beer and had an early dinner.
Day 4 I intended to explore a zone about 5 miles from the end of the trail for the Rokon. I had gotten close last year and although I didn't find any gold, there was a fair amount of old iron trash. I thought that I just hadn't walked quite far enough to find some virgin ground. My ideas were dampened a bit on the way up. I discovered that my newly repaired rear tire couldn't handle the low tire pressure and kept breaking the bead. We used the Mexican method of setting the bead by pouring some gas inside the tire and hitting it with a match. Whooomph, bead set, but I still had to run 20lbs of air pressure to keep the bead from breaking down again. I normally run about 4lbs of air in the Rokon tires since there are no shock absorbers as we know them. That much tire pressure was making the ride hard as a rock and I hit a rough patch that bounced me high and hard enough that I came unhorsed, landing my ribs on the handlebar. Ouch is an understatement. I've got a bruise the size of a softball over 3 of my left ribs. I gutted it out and still explored the new zone for no joy. I found 4 small ones on my way back in the bedrock I had worked the day before. Swinging that pick to break open the bedrock was a new experience with those banged up ribs.
Day 5 was the travel day home. You just never know how long the wait line at the border crossing will be. Sometimes as much as 2 hrs, this time about 45 minutes.
It's always a good trip when you can walk away from it. Minor injuries and break downs are all part of the journey. I'll be ready to do it all again in a week or 2, when these ribs quit hurting.
Let me start of by saying I heard about and saw some pictures of hugh silver and gold found in Arizona. If I find a link or the discoverer wants to post up his pictures I'll let you know. This find is not about that. This find is about a couple of good weather days in Arizona near Wickenburg if you follow on the map. I went there because of Bill Southern's outing that was very well attended. He'll have some pictures on his forum which I'll try to link here.
Minelab America was there giving away something to everyone who attended and they also had a raffle which benefited AMRA to the tune of $2700! This was near the second day and where the nuggets were found.
This first picture is a panorama of the area where I went the first morning. It is near a GPAA claim was a nice specimen was found last month.
As you can see the desert is not really dead. It has many living plants and animals. The fallen cactus is a saguaro. You normally only see it standing with its green skin but inside it is an engineering masterpiece. It is made of many rods that give it strength.
The next set of pictures is of the cactus that makes cowboys strong and forget about pain. These are the jumping cactus that get you over and over again.
I finally dug a hole but it was hot ground.
If you enlarge these pictures you will see in the picture some wild burros. There were about 10 with a couple of black ones.
The next day we stopped by an old mine on the way to a different claim.
Chet got us near and then we went off a less travelled road and we had to turn around. This is him coming out.
I didn't take my phone detecting this time because it lost power trying to find a signal. This was the claim where Chet found a nice 2 g nugget and I found the .25 g nugget.
These were my pictures on the way out at the end of the day and before my 6 hour drive back to Santa Monica.
I took a couple of bad picture of the nugget this morning with the phone. It makes me want to get a better one ... nugget and phone that is!
Steve has started a topic on the GPZ 19 coil and last Thursday I was using that coil in Gold Basin. Many of us have been to Gold Basin and we roughly know the conditions with gullies, benches, mountains and hills. Little of it is 'flat' but some of the benches are large and open. Some of the ground has been extensively worked with dry washers in the past and present.
My area for the day was on a slope in a well known claim and I wanted to find a deep nugget. I've heard that they are there so I have the right equipment. As luck would have it about 100 ft from where I parked I got a faint signal. It was repeatable so I know I had to dig it. The area was up on a higher slope of a larger gully and had not been worked with equipment. I scraped and scratched and could still hear the signal. Time to dig.
The signal got louder. I changed settings from normal to difficult and could still hear it ... maybe not a hot rock but it could be ?? I'm down now over a foot which exceeds most of my 19" holes so far and I can hear it getting louder so I go to the SUV and get my pin pointer, GB Pro and camera. Still too deep for the pointer and the GB Pro. Lu comes over with the 2300 and can't hear it either. Dig, dig more down next to a big rock ... is it the rock?
GB Pro now jumps around on the numbers 42, 75, 15 ... I'm getting close. Lu says it is a hot rock. I dig and dig with my long handle pick and finally it is out of the hole. I scoop and scoop looking for color and then ... TRASH.
It is an old, long 22 shell casing that has been damaged. Deep trash ... HOW? Never that deep before. Why?
It is my theory that the shell fell into a squirrel hole. It was not a surface target that fell into the dug hole. I'll never know but it was one of my deepest digs with the 19 (18" or so). It would have been great if it was a nugget that deep and it is one of the reasons I will continue to use the 19. I don't think I could hear that trash with the 14. (Writing this perhaps I should have taken the time to try.)
After my learning and disappointment it was time to fill my hole.
I wish it was a gold story.