Fisher Coinstrike
John Castle
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| If there is one word that manufacturers love to use, it is “innovative”. Sometimes what they are trying to sell is indeed a revelation, and I well remember the great leap forward the hobby took with the introduction of motion technology, upon which nearly all modern detectors are now based. So is Fisher’s latest offering - the Coin Strike - in any way innovative? After using it I sure think so! The Coin Strike is outwardly similar to other units in the Fisher range, and - in common with them - a motion detector. It sports the usual black and gold colour scheme, detachable control box and spider coil. Two PP3 batteries power the detector, each in its own drop-in compartment in the underside of the control box, and a standard quarter-inch headphone jack is provided. |
A quadrant on the upper side of the control box shows a range of targets and their numerical equivalents as shown on the screen. This is repeated in the handbook.
So what’s new? Fisher has patents pending on their new Digital Phase Analysis (DPA) and Adaptive Feedback System (AFS) that allow much better separation of non-ferrous items from ferrous. In fact, I found that the presence of iron mineralisation actually enhances the detectability of non-iron targets! There are no knobs and switches, just tactile push buttons and a screen. Switching on (push the POWER button) reveals more and reading the handbook reveals yet more still.
Controls
The operation of this detector might best be described as “Push the button, watch the screen”. Switch the Coin Strike on and the four main controls appear as schematics of standard rotary knobs, which “turn” up and down as you press one of the two arrow buttons. Battery voltage will also show for a couple of seconds.
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Display panel in search mode |
(Tip: There is also a four tone discrimination system - iron, low, medium and high, plus overload if items are too close to the coil. If DISC is set to 99 the iron tone will not be heard).
Normal discrimination is via four windows, which are displayed vertically on the right of the screen as cursors. To adjust press MENU until “Number” appears, and then use the arrow button to select the one you wish to turn on or off, when it will blink. Then press the ALL METAL/DISC button to switch it on or off. If on (reject) it will blink slowly, if off (accept) it blinks quickly. You can turn each one on or off individually. When you’ve finished press P/P MEM and the accept cursors will remain while the reject ones will disappear.
(Tip: I found turning on window one was enough discrimination on all the sites I used the Coin Strike on. The tone/numerical disc system did the rest!)
A two digit number will appear on the screen when a target is located; the higher the number, the more conductive the target. Negative (minus) numbers are iron and these numbers show on each target whether or not the discriminator rejects them. THRESH is threshold and this functions unlike any other threshold control I have ever used. It is marked from 0 to 10 but the screen numbers vary from -99 to +4. A tone will be heard if set above zero. It works in conjunction with SENS, and turning one up and the other down will optimise performance on any site once the user becomes familiar with the unit. When the UP button is pressed the threshold goes down and the control turns clockwise. The control thus displays a rough indication of how far below zero it is set. Press the DOWN button long enough and a tone will come in, the control will turn off, and the screen numbers will maximise at +4.
(Tip: Don’t be afraid to reduce threshold on difficult ground conditions. It is not like any threshold control you might already be used to. Most people like to hear a constant tone and it as available for those who do - ground conditions permitting of course. Get it and the other controls right and performance will be maximised).
Press P/P MEM when you’ve finished. VOLUME and SENS are standard volume and sensitivity controls. Access via MENU, adjust via the arrows, and then press P/P MEM when you’ve finished. LIGHT illuminates the screen in low light conditions. Use only momentarily when you need to see the screen to save battery power.
AUTO GROUND is an easy way to ground balance. After setting the other controls and returning to the search mode, find a patch of ground with no metal in it. Place the coil flat on the ground, press and hold AUTO GROUND for a couple of seconds, and then, still keeping it pressed, lift the coil about 6in from the ground and release the button. You need to make sure you do not tilt the coil, keep it facing to the ground. The Coin Strike will beep to confirm balancing has been set.
AUTO GROUND also has another function. Press MENU until S0 shows on the screen. This is for sites away from wet sea beaches. Pressing AUTO GROUND changes this to S1, which should be used on wet sea beaches and should be set before adjusting the other controls - including ground balancing. As usual, press P/P MEM to store and exit.
(Tip: Should you be unlucky enough to be hunting an ironised (black sand) wet beach turn S1 to S0, reduce SENS and THRESH, reset AUTO GROUND and turn TRACK on).
The handbook gives more precise advice. TRACK switches on AFS (see above) which is a fast auto ground tracking system that Fisher claim will not track out targets which has been known when similar systems are incorrectly set. Fisher recommends you use this on wet sea beaches with a reduction in threshold for best performance. This may not be the best option on all beaches, of course, and may well be so on inland sites. Experience will tell you!
If you later switch TRACK off the Coin Strike will default to either your last AUTO GROUND setting or the FP (see later), whichever was set immediately prior to switching TRACK on. P/P MEM is used to exit from adjusting to search and also pinpointing. To achieve the latter, press and hold. Sweep slowly over the target and the tone volume and highest number shown will indicate the centre of the target.
ALL METAL/DISC sets the windows as above and also permits detecting in a true all-metal mode, if desired, when just a single tone will be heard on targets but the number system still functions. The words DISC or ALL METAL appear on the screen in accordance with whichever one is set.
AUTO GROUND and TRACK both function in this mode as well as the DISC one.
ALL METAL/DISC has another function, called numeric ID averaging. Press and hold and A or A1 will appear and will alternate if the button is held in. Normally A will be on, which will give a real time number indication as a target is swept over. But if bouncing between numbers occurs, it might be better to switch to A1. This averages the numbers and is thus more stable.
You can store up to three of your own settings by using the STORE function. Once you have set the Coin Strike up for a particular site you mean to return to, press MENU until a blinking MEM appears. Use the up and down buttons to select 1, 2 or 3 (FP will also show) and press and hold P/P MEM for a few seconds. When the settings are stored MEM will blink twice and a beep will be heard. To access, repeat the above until you get the location you used, and then again press P/P MEM for only one second and release. FP is factory preset and is accessed as described previously. The handbook shows the factory settings.
(Tip; When you visit a new site, start with FP and switch the second window off; only then progress to adjusting the other controls. On wet sea beaches turn S1 on before you adjust anything else).
As you gain experience it is helpful to experiment, but you can always return to FP and start again if you get lost.
As well as the initial battery condition display when the Coin Strike is turned on, there is also a low battery alert. This is a wavering tone coupled with LOW BATTERY appearing on the display. When the Coin Strike is switched off your last settings will be retained, it does not default to FP. The exception is for S1, which is not retained. So, if you have been wet beach hunting and wish to resume with the same settings at a later date, don’t forget to switch S1 on again.
If you wish to use TRACK don’t forget to set AUTO GROUND first (which can also be used without TRACK of course).
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Close up of Coinstrike hip mounted |
The handbook is in Fisher’s usual A5 format. While the Coin Strike is not difficult to use, it is innovative and studying the handbook with the detector to hand will pay dividends in the field.
The control box is splashproof. A three-piece stem enables easy stowage in a holdall. The coil is an 8in spider type but no doubt other sizes will come along later.
(Tip: When placing the control box onto the triangular plate above the handle, support the handle with your other hand to avoid straining the plate where it joins the stem. If you wish to body mount the control box, remove the triangular plastic plate from the handle. It tends to get in the way and could get damaged. Just one screw holds it in place but don’t lose the screw!).
The Filings Ring Test
A plastic ring full of iron filings is a very severe test for any detector, and you will be most unlikely to encounter similar adverse field conditions. Nevertheless, it is a test and there are not too many detectors that can pass it. The procedure is to ensure the filings are rejected, and then place a find in the ring to see whether or not it is rejected along with the filings.
Where the detector can accept the target its response is invariably degraded compared with its response away from the ring. This is not the case with the Coin Strike! In my tests I used a hammered penny, a Victorian half sovereign and a bronze Roman coin, and in all three cases the response was better when the object was in the ring than when it was out.
This advance is due to Fisher’s grappling with the problem of black sand, which is the highly ironised soil detectorists are cursed with in many areas of America. The spin off for us is more of those elusive deep, small finds from bad ground! I believe this to be a true innovation.
On The Beach
At first I was puzzled. I had been experimenting with the Coin Strike at home, had set it miles away from FP, and it obviously still wasn’t happy on the wet sand. I therefore re-thought what I was doing. I simply pressed MENU until FP came up, turned the third window off, S0 on, and away I went.
The unit was perfectly happy and coped as good as anything else I have used. I had the odd false signal and so I reduced THRESH and SENS slightly and turned TRACK on. This almost eliminated the false signals and those left were too few to worry about. The usual coins, fishing weights and alloy junk came out from good depths; in fact, better than usual in some cases. No rings came to light so I buried my own 9ct wedding ring. In doing so I nearly lost it! The hole quickly filled with water and sand, and the infill wouldn’t come out on my digger. I had to get on my knees to find the ring by groping about almost up to my elbow. Whether I found it easy to retrieve the ring or not, the Coin Strike was still responding to it.
On A Local Common
I have searched and tested other detectors on this particular common many times before. The part I chose has produced more older finds and less modern rubbish than other parts. But this doesn’t mean that rubbish level is low, there’s still plenty of it.
Once again I started with FP and turned the third window off. The ground is quite bad in places but I was able to increase SENS a bit and reduce THRESH a bit which gave good, deep results.
My first find was an 1881 penny; the piece of silver paper in the same hole was the only bit I found all morning. The oldest coin was a George II halfpenny, recovered from some depth, and so worn it was identifiable only by the outline of the head.
My deepest find was a toy clothes iron at nearly a foot. This is too large to be dolls’ house furniture but a bit on the small side to be gripped by a child’s hand. Made of white metal and unmarked, it represents a bit of a puzzle!
My best find was a nice 1887 shilling. Another good signal produced two pieces of free-blown black glass from a 17th-18th century bottle. The target was too deep to get out easily and I gave up hoping it wasn’t a clutch of guineas buried in a bottle! I will return when the ground is softer.
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This toy clothes iron was a very deep find |
I used the Coin Strike on a couple of these, plus another grassy area. Again, I started with FP, turned the third window off and set AUTO GROUND. On the first stubble field I got some false readings, so I turned SENS and THRESH down a bit. Later I tried turning SENS back to its FP setting and things were still fine.
I dug no iron except a small electrician’s screwdriver. This gave an ambiguous response, dropping below zero then responding just above it. The field - or rather the Coin Strike - produced quite a few non-ferrous odds and ends, including a nice patterned pewter button.
Considering the stubble, depths were most acceptable and would be even better when the field is ploughed. The second field, also stubble, was worse, mineral wise, than the first one. I dropped THRESH to -20 and left SENS alone. This worked fine. I made far fewer finds here, but it produced the best one, a hammered groat of Charles I.
The grassy area is not a proper common, just a rough area frequented mostly by dog walkers. I had never bothered with this area before as such places usually contain little more than ring-pulls and dogs’ visiting cards.
I was right so far as that went, but quite a bit of modern coinage came out too. The oldest was a 1950 shilling. The ground was excellent, with little iron, so I hunted in all-metal and turned both SENS and THRESH up, the latter until it was just on the verge of producing a continuous tone.
The grass was very matted and hard to dig, but the ground beneath was as soft as can be. Although most finds were shallow, being modern, a few were deep and the Coin Strike got them easily. A tiny cockerel, which I thought was silver but isn’t, came out at a good 5in in the ground. Adding the matted grass made it nearer 7in and you can’t grumble at that!
I found just one bit of iron. This was of a strange shape with a point at each end, and it had a round hole in it. That was deep too! Throughout all this, the number system generally locked on to each target with great consistency and very little “bounce” providing SENS and THRESH were properly set, but I did note the following. The numbers that bounced a lot resulted from junk silver paper of the thicker or larger type. Where these did give a solid tone response the number would be from zero to about +8 to +11 and pinpointing gave a fluttery response, rather than the solid response it normally gives.
I found pinpointing excellent by the way, and it equalled the depths of the DISC mode, which isn’t always the case on motion units. The photographs show just some of the finds I made, during the field test.
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Looking back, I have to conclude that the Fisher Coin Strike is an innovative unit. It isn’t difficult to use and thus preserves Fisher’s aim of versatility coupled with improved depths and sensitivity, especially in ironised ground.
The THRESH (threshold) control takes a bit of getting used to, but it is soon mastered providing the experienced user can get over his inbuilt reluctance to run it far lower than he is used to on some sites. Setting it, with SENS, is crucial and AUTO GROUND and TRACK, when set properly, will enable the user to obtain excellent results on almost any site.
Versatility and top performance equals complexity? Not necessarily, as the simplicity and elegance of the Fisher Coin Strike amply demonstrates. The hobby has just moved on again!
The Fisher Coinstrike is available from Joan Allen Electronics Ltd, 190 Main Road, Biggin Hill, Kent TN16 3BB, UK. Telephone: 01959 571255, Fax: 01959 576014, E-mail: sales@joanallen.co.uk.
Reprinted with the kind permission of John Castle and Treasure Hunting Magazine.
© Reproduced with kind permission of Treasure Hunting Magazine.
