F75 SE Metal Detecting Review:
I first tested the Fisher F75 for the May 2008, I was so impressed that I rushed out and bought one. So when I heard that an updated version had been released, I just couldn’t wait to test the new ‘Special Edition.’ Out of the box everything looked very familiar, the large display, the rotating control knob and single push
button. It still uses the same trigger switch below the control pod to operate the pinpoint, frequency shifter and ground balancing. The only obvious visual change is in the colour of the upper stem, which is now black and not gold. I must admit I was a little apprehensive when I first switched it on, hoping it wasn’t just another ‘black upgrade’ with minor changes (e.g. bug fixes)…but I needn’t have worried!
On firing up the new F75 SE and toggling through the controls I noticed additional processes (programs). There were still the four original programs; dE (default), jE
(jewellery), bc (bottle cap) and PF (ploughed field), but now there were two new ones, bringing the total to six and bringing this program driven metal detector 50%
more functionality. The first of these new programs is called bp (boost process), which operates with enhanced sensitivity and a slightly slower recovery rate. This program should be great on pasture, giving extra depth in soils with milder mineralisation. Operators will need to slow down their sweep speed in trashy areas, as this program has a slower recovery rate than the original programs. When the bp program has been selected, it will affect both the All-Metal modes (more later), giving less noise and slower response speeds. Next is the CL (Cache Locating), which is an enhanced sensitivity version of the default program. In the instructions it states that in many situations, you may prefer to do cache locating (hoard hunting) in ‘motion All Metal’ mode. But what surprised me… no shocked me, was the depth of this program when used in the Discrimination Mode. I’m not talking an extra inch or so, this program really punches deep and on hammered coin sized objects.
In my last F75 field test I went into greater detail than I intend to do this time. All the control functions, menu system and visual display layout remain the same. The F75 still has two discrimination systems, a traditional progressive system, and a notch system for specific target control. It also has a useful seven-channel frequency shifter (noise cancel) to help control interference from other detectorists, power-lines, phone masts etc. This is operated by holding the trigger forward and pressing the button to toggle through the channels. NB: On really bad sites with lots of electro-magnetic interference, it may still be hard to find a quiet channel, so users should lower the sensitivity until the noise reduces to an acceptable level. The new detector has the same fast grab ground balance feature
of its predecessor, which is easy to operate by pushing the trigger forward momentarily, and then pumping the coil up and down over a clear area of ground.
There are three search modes; Discrimination, All-Metal Motion, and All-Metal Static. Discrimination is a non-threshold search mode where discriminated trash items are not heard. You will hear some chatter from ground anomalies, but these tend to be easy to recognise. In addition to blanking discriminated targets, you can select a sound process to allocate different audio tones to certain groups of metals within the detection range. There are eight different tone modes to choose from. These set the number of tones between one and four. Out of all the eight choices I preferred the 2F tone, which gives a low-tone to iron and a high tone to everything else. The second search mode is All-Metal motion. This mode has a single tone for all metal targets, and you discriminate using the target identification number in the visual display. When using this search mode there’s no chatter from the ground, but you will need to keep a constant eye on the display if the ground you are searching has lots of trash. Because this mode has a constant audio threshold, it’s possible to hear faintest of target responses, the ones giving only the slightest of rises in the base threshold hum. The last search mode is All-Metal Stat (static), which is the same as the last program with out the ground tracking ability of the
motion detector. On really deep targets on the edge of detection will not be tuned out. I personally consider this as a specialist mode ideal for hoard hunting. In most detecting situations you will probably stick with the first of these search modes: Discrimination.
I first went over the test bed using the default program (dE) with a discrimination setting of four. I found I could run the sensitivity at ‘80’, which made the F75 very sensitive while keeping it stable. The detector hit every target giving strong audio responses to the target in the first 6”. Deeper target at 10” gave faint soft whisper responses. Keeping the settings the same, I changed just the process (program)
in turn noting the changes to performance. jE (Jewellery) gave similar responses, although I felt the iron chatter was shorter and easier to identify. There was a subtle improvement on the deepest targets, giving them more substance.
The next program I chose was PF (ploughed field), which improved the responses further and decreased the chatter slightly. PF was probably the best sounding program for easy identification of all good targets (for my hearing). I then switched to bP (Boost Process) and the target responses – even the deepest – started squealing, making them standout even better from the low-toned iron. I did have to slow down my sweep speed over any target sitting close to iron. In this program a few iron targets started giving me one-way positive responses. However with a bit of tweaking of the sensitivity, this program was the best for deep targets in the clearer areas of my test patch. As the ‘Boost’ name suggests, the target responses are boosted making deep and shallow signals sound alike. The last program I’ll cover is the CL (Cache Locating) process, which gave the strongest responses to all targets. It did struggle to separate some of the targets from iron, but with a slow sweep and a ‘wiggle’ over the iffy targets, it would eventually lock on giving strong positive responses. This program is unbelievably powerful, and if used on relatively low mineralised sites, with low iron contamination, depths achievable should be awesome.
In the field
I set up the new detector in my favourite old F75 settings; default (dF) process, two tones (2F), discrimination 4, sensitivity 80 and I was soon pulling out the usual deep musket balls, shotties and dandy buttons this field always seems to produce. I was soon wandering the field in autopilot, enjoying the sunny spring weather (Figure 4). It was while digging another deep signal, still daydreaming when I suddenly found myself staring down at something gold glinting through the soft sticky mud. Wiping it gently on the towel hanging from my waist, I could see I had found a beautiful Celtic gold stater. This was totally out of the blue, and unexpected. I can’t remember getting the signal, what it was like or what made me dig it…but I’m glad that I did! (Figure 5) With extra vigour I started gridding the area, hoping to find another. About six feet from the stater I got another good signal. With my heart still racing I dug down deep, and out popped a familiar grey disc in the first spade of dirt, it was a rather nibbled hammered Edward penny. Two good finds in two signals, it doesn’t get much better than this (Figure 6). The next site I tried was a building site, where the topsoil had been stripped along the side of a stream. This stripping had exposed the buried dredgings – and I knew that this waterway navigated in the Roman period. On previous searches on other sections of stripped soil, Roman coins had been found. I was hopeful that coins
where possible from this iron contaminated material. caps are usually deeper than 8”. I fitted the SEF coil and selected the bP boost program. The SEF seemed to be slightly noisier than the waffle coil, so I reduced the sensitivity to 70. I then proceeded to dig shotty ends…one after another after another. After two hours
I had 30 of the damn things, and although I could’ve notched them out, I wanted to see at what depths the new detector would go down to…over 10”.
The first F75 was a great detector, proving to be one of the deepest single frequency detectors available. The new F75 Special Edition is even better, going deeper with more sensitivity. The extra two processes (bp and CL) are really powerful, and I’m sure I’ve only scratched the surface of their capabilities. In my
original test I struggled to find anything negative I didn’t like, settling on its annoying habit of falling to the side when laid down on the ground. I can report that the new model is still just as annoying! This only really happens using the waffle coil, because of its round-bottomed construction, the SEF makes it more stable. So that’s my only gripe (as petty as it may seem) and this new detector is otherwise fantastic. It has also proved to be a very lucky detector for me, finding enough during testing to warrant me buying one…something that doesn’t happen too often!