TEST REPORT OF THE FISHER CZ20
BY ALAN HASSELL? copyright 30/1/1995
CZ20 CONTROL BOX.
It was bound to happen sooner or later, Fisher metal detectors have just released their new CZ20 underwater metal detector. For many years now, detectorists have been looking for a good all round machine that could cope with the rigors of underwater detecting and serve as a land based machine too. It is based on the highly appraised Quick-Silver or CZ-6 that has built an enviable reputation for locating small valuable targets at great depth in Europe and the USA. Fisher, thoroughly test their products both in the field and development laboratories ensuring buying public get what they pay for.
Numerous attempts to market VLF machines as a good, reliable underwater detector, have in the past proved a nightmare for manufacturer's. However it must be remembered, that Fisher introduced their now famous (1280X) many years ago and have a leading edge over their competitors owing to it's success and reliability. Fisher Research Laboratories, are noted for the high quality of workmanship built into their products, having spent many years satisfying the buying publics needs.
Development of the CZ-20 started shortly after the CZ-6 release about 1990, but being designed for use underwater took longer to perfect. Since I am still the only individual in Australia who writes and promotes my hobby of shallow water metal detecting, it's not surprising that I get offers to write test reports of new machines coming onto the market. The problem is one of integrity, I could write glowing reports about a useless piece of rubbish and lose my credibility in the process.
I initially refused to even look at the CZ-20 when I heard that it was a VLF. I agreed to test it on condition that I could write about the bad points as well as the good points, as I owed it to my readers who come first as potential buyers of anything in the marketplace.
FIRST IMPRESSIONS.
Presentation, is perhaps the most important item one considers when buying anything, be it a car or whatever. Therefore when you see the luxurious foam filled moulded (Samsonite) lockable case the CZ20 is supplied with you are instantly impressed. The Control housing is the well tried and tested housing used for many years on the 1280X, little wonder it's hard to tell the models apart. Although the housing design could be considered old, it is one that has stood the test of time and proved reliable over the years. The entire housing is factory sealed except for the battery pack, which is secured with two knurled knobs.
The unit is powered by 4 X 9 volt alkaline batteries providing between 35 to 55 hours of searching in the water or on land. he unit comes assembled except for fitting the coil to the search rod. Fisher make two spider coils, 10 and a half inch or 8 inch. Coils are not interchangeable and choice must be made at time of purchase.
The model I tested had a ten inch coil fitted, which is what I prefer for water use. The telescopic search-rods are constructed of high strength Fiber-glass. Collapsed they measure 41'', extended 50''. A superb expandable foam lines stainless steel arm rest is fitted to the top end.
CONTROLS
The CZ-20 is fairly simple to operate especially as it has only four controls, Fisher has made it easier for you because each control has a pre-set mark, so a beginner can simply switch on and start recovering goodies. The controls consist of combined on/off Volume/Boost, Sensitivity, Sensitivity/Battery check, Discrimination/Audio-tune and Ground balance. There is also a special button used to pinpoint targets and two L.E.D.s used for battery testing and target response.
VOLUME.
A special feature of the volume control is a special boost mode, when set at about (5) large target response is held constant while faint signals get louder. Increasing the volume above (5) will amplify the response of a faint target so they sound like a shallow or large target. Some searchers prefer to keep the volume at 5 so the audio response will give them some idea as to the size and depth of the target.
SENSITIVITY
Only experience will tell you how to set your sensitivity control in every situation. A good method of setting the sensitivity is to turn to Auto- Tune and increase the sensitivity so you can barely hear a slight audio hum. Setting the sensitivity too high can cause erratic and false signals, these are eliminated only when the sensitivity is reduced. Battery Test is incorporated into the sensitivity switch, turn control to extreme left, turn Volume to Max and both LED's should light up. If they don't, it's time to replace the batteries. I should point out at this stage that only ALKALINE Batteries should be used at all times.
GROUND CANCELLING.
The manufacturer's emphasize the need to ground control the CZ-20. Proper use of this control will minimize false ground signals and ensure the machine is operating at it's maximum potential in just about any ground including wet ocean sand. Those of you familiar with manual VLf machines can use the old bobbing the coil up and down to ground cancel. However Fisher have incorporated a fast push button method. Set ground control to 10 make sure no targets are in the area, hold coil 6-12 inches off the ground. Press Pinpoint Control as you lower the coil to the ground turning ground control clockwise until you hear audio tone. Back off the control until tone disappears, release the pinpoint button and your ready to search. There is a third Easy method of ground cancelling that is to use factory pre set markings.
DISCRIMINATION
The CZ-20 uses two methods of discrimination Tone and Notch. There are seven notch modes marked from 0 to 6, the highest setting. As an additional guide to help you identify buried objects, three tones can be heard in the earphones depending on the target. A Low tone indicates nails, bottle tops and ferrous objects, most gold rings fall into the medium tone range. The high tone indicates coins and some gold rings.
There is an additional Bell Tone, which is named because it does sound like a bell or telephone when the user goes over large tin cans etc. This is really useful because today's youths take cans of beer into the water and leave them there. The only problem is if you don't remove them you never know if there was a better target underneath. Some people fail to understand why they sometimes dig up iron target when they have set the discriminator to reject it.
The answer is simply the size and shape of the object buried. We have to accept the fact that no matter what detector we use, at some time will have to dig an unusual target. Sometimes you get marginal sounds, when sweeping the coil one way, you may get a medium tone, and a high tone in the opposite direction.
An explanation of why this occurs happened during a lecture I gave at a metal detecting club recently. I swept a mans signet ring over the coil to demonstrate depth and sound, unbeknown to myself, the angle of the target changed in mid air as I returned the target across the coil.
The explanation is the angle at which the coil sees the target, much like hitting a coin on the flat in one direction and a coin on its side in the other. High and medium tones represent good targets, failure to dig them would only be your loss.
The easy to follow instructions supplied with the CZ-20 goes into lengthy detail about target identification that is far too long to include in this report. Testing the CZ-20 The first thing anyone should do before attempting to use a new detector out in the field is to set up a number of targets onto a clean metal free piece of ground to familiarize yourself with the numerous sounds and depths one can be expected to encounter. Mick Killeen who assisted me with these test was surprised at the depth the CZ-20 located the targets in air.
The Special Pin-point mode built into the CZ-20 changes the signal into a wide signal, the centre being where the sound is loudest. We, agreed, that although it does not have the depth of the latest pulse induction machines,
The CZ-20 comes pretty darned close. Having familiarized myself with the controls and general sounds the detector made, the first place to try it out was obviously the beach. Before even trying it out on the dry sand, I went straight onto the wet sand that plays havoc with most VLF type metal detector's. I felt that if it couldn't handle the wet sand, it was pointless making any further tests.
Surprisingly, the CZ-20 handled the wet sand with the greatest of ease from the waters edge right up to the dry sand. Although is does work in a silent mode, no false signals were experienced and the tone discriminator worked well. Knowing it could now handle wet sand, my confidence in the machine increased and set about exploring just how good the CZ-20 really was.
Up on the dry sand I detected numerous old 2 and 1 cent coins that had been buried many, many moons and wondered why they hadn't been recovered before. The answer of course lay in the depth of the coins which was beyond the reach of most detectors. Working on a theory, that if this was the case, then the only way to put the CZ-20 was to try in out in school sandpits and playgrounds.
These area's are hit by every Tom, Dick and Harry and they don't leave much behind, or do they? I was using a small stainless steel gardening trowel to retrieve my targets when I suddenly realized that the CZ-20 was picking this up at a depth of about 30 inches. So I repeated the test and got the same result, The signals were not due to bad ground cancelling or discrimination, it just that the CZ-20 is a very powerful machine.
This test was witnessed at a later date by Ian Aitken of Miner's Den in Melbourne who like myself was surprised to say the least. Whilst I was in his shop, I tried the same test out on one of Minelabs,
Sovereigns which is now being sold as an Excalibur.
The CZ-20 had a much better depth advantage over the Sovereign which could only pick up my trowel at 24 inches against the CZ-20s 30 inches. It wasn't long before the old shillings, 2 shillings, penny's half-pennies along with a few one dollar coins missed by others were in my hands.
Owing to the depth of some of these targets, I had to return to the car to get my Estwing Pick, simply because it was hard going with a trowel. When I told Mick about my experiences, he wanted to try the machine out for himself. He thought I was trying to pull the wool over his eyes and wouldn't believe me unless he witnessed it for himself. So I let him use the machine for a couple of hours only to confirm what I had told him.
Mick like myself was surprised by the depth he had to recover targets from. One thing came out of these test was the need to use the hip mounting attachment supplied by Fisher. Although the CZ-20 is a heavy machine to use on land, it is quite the opposite in water. The coil stays submerged but not on the bottom, floating about a foot off of the bottom and the control box beside you on the surface. The more I used the CZ-20, the more I was enjoying using it and began to get the feel of what was becoming an awesome metal detector.
Next test, you guessed it, in the water, I was a bit apprehensive at first but once in the sea I turned the unit on and started to get familiar signals I had encountered in the school yards. I used it initially in the auto-tune mode to ground balance the detector and used it for a while in this mode. Setting the discriminator at (0) all the sounds came through and it was nice to know when I was over iron targets.
I then started to search methodically and turned the discrimination up to (1) to avoid digging time wasting targets. My stainless steel scoop is nine inches long, using a PI it is not unusual for me to dig several scoops to recover a target. I must admit that sometimes a target will fall out of your scoop back into the hole. One and two cent coins came out of holes if not in the first scoop, it would be in the second. Ten cent coins were the same.
When it came to 20 cent coins it needed 3 scoops before the target finally surfaced into the sieve. The CZ-20s ability to discriminate in water without losing depth is really amazing. Although I was only in the water for two hours on my first adventure I did recover coins, key rings and five electric fuses.
No gold on the first visit but it's only a matter of time, I know it's there waiting and when Davey Jones decides to open up his locker, I will be there to take advantage of it. Unbeknown to myself, my pal, Mick Killeen, who had helped me test the CZ-20 was so anxious to get his hands on one, That he phoned Fisher's in Sydney to get one.
I was using the only one in the country and he knew it. That evening I had a phone call and had to take the CZ-20 over to Mick who was the new owner. I was hoping to have had more time with the CZ-20 just to have proved to myself you can find rings with it. At least my major fear about it's ability to handle salt water that causes most VLFs to become erratic and give false signals were overcome.
SUMMARY.
If I were to give marks for every feature including it's performance, I'd probably mark those features excellent. The CZ-20 proved it could handle every situation with ease and great depth. Something that can be verified by other users. In a comparison test using a Gold Sovereign Signet Ring the CZ-20 had a 4'' depth advantage over Minelab's Sovereign metal detector.
This machine is now marketed as an Excalibur. Mick's made numerous good finds with his CZ20 since he took possession of it some very nice gold rings. One with a 2 carat stone returned his investment. The text of this article was taken from the published version, anything missed out was probably edited out by the editor. ends. ?
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