CZ-21

Just the handle, Grant. I replaced that to the tune of $17 including shipping. The techs at Fisher were able to do that. I called and left a message for Dave Johnson again today. He must be in as his voice message was different from yesterday. Again, still waiting for a call back. I guess customer issues are not a problem for Fisher engineers to address. That was the nice thing about dealing with Whites Electronics in Sweet Home, OR. Everyone was there to help a customer.
 

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In an air test in an environment free of electrical interference, I'd expect the 11 inch semi-elliptical to hit coins an inch or two farther out than the 8 incher. In the presence of electrical interference they'd probably be about the same on "air depth". In the ground on buried targets, in general I would expect the 11 inch semi-elliptical to have an inch or so over the 8 incher on coin size and larger targets, but in bad mineralization under some conditions the 8 incher might actually deliver the goods a little better.

Since I wasn't involved in the service issue and don't work in that department, I'll refrain from commenting on that directly. I'm merely providing general information about the searchcoils.

http://www.fisherlab.com/hobby/davejohnson/searchcoils essay revised.htm

--Dave J.

PS: I received no phone voicemail message yesterday, haven't been in the office today, and the last time I changed my canned voicemail message was months ago. So I don't know what any of that is about.
 

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Dave,

The voicemail that I was directed to yesterday was not the same that I got today asking for you directly and not being forwarded by a technician like I was yesterday. I totally agree with your assessment. The 10.5 inch coil should be hitting deeper than the 8 inch and there is no EMF or mineralized soil conditions in MI. I can only assume that there is a problem with the CZ 21 with the 10.5 inch coil. It could be the coil or an adjustment or even possibly a component that is going bad on the board. With what the techs were saying to me, I hesitate in sending it in as they said that they would do nothing to troubleshoot the issue being that it will hit a quarter in the ground at 9 inches whereas the CZ 21 with the 8 inch coil will hit the quarter at 11 to 12 inches. It really should be the opposite way around with a mono coil. The larger coil should hit deeper on a decent size target (a quarter being a decent size target). I can see that the smaller coil will hit smaller targets better that are closer to the surface. The tests are the same with the target now burried at 9 inches for 2 weeks with sandy loam soil that is now wet....jim

BTW, Dave, the coils on a CZ 21 are round mono coils and are not elliptical or semi-elliptical.
 

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Checked in at the office this evening and both messages were on my phone.

Sounds like the difference you're seeing is the difference between the machines, not the searchcoils unless the 11 incher is defective.

The 11 inch coil is a semi-elliptical (round transmitter, elliptical receiver) coplanar concentric, the 8 incher is round coplanar concentric (I know what they are, I designed them.) Nothing we presently manufacture uses a mono coil although the long-extinct Fisher Impulse did.

--Dave J.
 

I'm the original owner of the 10.5 machine. I found some real deep targets with it both in dirt and on the beach. Never compared it to a 8.5 though

Dave, great design on the coil. I've never had an easier and more accurate experience pinpointing.
 

woof! said:
Checked in at the office this evening and both messages were on my phone.

Sounds like the difference you're seeing is the difference between the machines, not the searchcoils unless the 11 incher is defective.

The 11 inch coil is a semi-elliptical (round transmitter, elliptical receiver) coplanar concentric, the 8 incher is round coplanar concentric (I know what they are, I designed them.) Nothing we presently manufacture uses a mono coil although the long-extinct Fisher Impulse did.

--Dave J.
Click to expand...

Dave,

Both coils are concentric (round) and are advertised as a 10.5 inch coil and an 8 inch coil by Fisher. It seems to me that the problem is not with the coils but with the unit itself with either a component on the board or with an adjustment (settings). Although it is also possible that there is a problem with the coil or connectors. The question is and the point of this dissertation is what to do to fix the problem, as it is a problem that should be addressed. The technicians that I talked to both stated that the unit was working properly and that they saw no problem with the larger coil getting less depth than the smaller coil on a coin. Grant is correct in that both coils do pinpoint very well and I can only compare the pinpointing ability to a standard 10 inch concentric coil for a Whites MXT. It is very accurate and I could not see why some folks complained of the pinpointing ability of the CZ 21. It is excellent.

Since I was forwarded to you by one of the techs, it was my belief that you were presently working and would have returned my call on either day(2 calls made by me over 2 days) . I still have not received a return call from you or from the proper service person concerning my inquiry. I can certainly understand that all of us needs and deserves time off for many reasons and I do appologize for taking up your valuable time to reply to a customer's inquiry.

Now, as the designer of those coils, will the 8 inch coil hit on a buried quarter deeper (by a couple of inches) than the 10.5 inch coil in sandy loam soil that is not mineralized with no EMT? I cannot think of a way to make this question more simple....Jim
 

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I've explained what can reasonably be expected in a comparison between the two sizes of searchcoils, no need to rehash all that. Just going from your description and assuming that you know how to compare the two machines correctly, it sounds like there may be a problem with the machine that's got the larger searchcoil.

--Dave J.
 

Thanks Dave,

I would expect that if the coil or coil connections were the problem it would either work, not work, or have intermittant connection issues. I think that the coil is excellent like the 8 inch. You did a wonderful job on the design of those coils and am surprised at the depth and pinpointing ability of the two coils. The unit, as a whole, is very well built.

Who should I contact to honestly get the unit looked at and repaired. It is obvious that the techs, that I talked to, think that it is a turn around (send immediately back without repair) with the 10.5 hitting between 8 and 9 inches. You CAN PM me with that information and phone number and extension of who I should talk to. I still have not received a return call from you. I would welcome that when you do get back to work, and I know how that can be as I just spent the whole day doing a pre-op at the hospital, that you talk and explain the problem with whoever you need to in repair so that it will not be "rehashed" again what the problem and resolve could be....jim
 

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I'm not gonna get in the middle of it, Jim. I don't work in that department, have no authority over that department, didn't have anything to do with the prior contact, and there are no engineering issues needing my input. If you don't want to talk with a service tech, you're welcome to call the company and ask to speak to the customer service manager.

--Dave J.
 

Thank you for all your help, Dave, and for not returning my two calls......jim
 

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AA,

Maybe you could send in the unit with a 10" coil and have Fisher put on an 8" coil instead? I assume they would recalibrate it as necessary too. I have found, as I am sure you have too, that I get equal or superior depth with a smaller coil at times, especially when the soil has mucho minerals.
 

That is an excellent idea, dbsmokey. It would give me a backup detector for Florida and Alabama fot the winter. Right now, I am coming to terms with a knee replacement in less than 2 weeks and have dismissed the dismal response from Fisher. Somehow that is not important right now......jim
 

I just got a call from a director of sales at Fisher and the conversation was very positive. Since both units were bought used, there will be a fee for recalibrating the CZ-21 with the 10.5 inch coil and the coil will also be checked for properly fixed inductive reactance and resistance plus the connections. I asked for a ball park fee and although reluctanct to do so, he will get in touch with Felix to call me with a very wide ball park estimate. He also agreed that the 10.5 inch coil should be hitting a quarter in the ground deeper than the 8 inch coil. Felix, the man at the factory, was a great listener and I am sure that he did an excellent job in trying to get this correct. I will keep all informed as to what the outcome will be.....jim
 

I decided to delete my explanation as to why smaller coils can sometimes go deeper on certain-size objects, but the problem can be fixed, so it doesn't matter now...HH all..
 

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Fisher received my unit but I will be in the hospital for a few days and will not know what the outcome will be until next week. The fisher coils for the CZ-21 have 2 wound coils inside the main coil. There is a sending coil and a receiving coil. On the 10.5, the receiving coil is elliptical. It should receive a stronger signal back from a quarter sized target than the 8 inch coil which also has a receiving coil and a sending coil which are both round and smaller. The quater is fixed and flat. A VLF signal is like a V so the larger coil should cast a larger V. A quarter should replicate the size of a man's silver ring and with all the folks that I talked with, the larger coil should hit that target deeper than the smaller coil. OP tomorrow at 6am....wish me luck with the new knee....hope it works....jim
 

Well, here is the outcome. It was a very positive experience with Fisher. Felix, the coordinator, made sure my service experience was on a par with Whites. It turned out every bit as good as Whites service. The detector, the CZ 21 with the 10.5 inch coil was recalibrated and that was no easy task. It has to be taken apart, calibrated, and then put back together again with many seals to withstand 250' of pressure. Felix knew that I was in the hospital for a knee replacement and also knew of additional complications with heart and lungs that I encountered. I am still fighting on those fronts. The charge for the extensive work was nothing.....yes 0$ and that included shipping. It works like it is supposed to now. I get about an inch or two on the 8 inch coil but more importantly, I can cover more gound faster with the larger coil even though the depth is about the same. Fisher Labs did me good and I appreciate it and would highly recommend their service. The detector came back looking and acting like new.....jim
 

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Arizona Ames,

I am happy to hear you got such good service. It sounds like Fisher took care of you! I wish you a speedy recovery so you may go out and use those machines. I look forward to hearing your results. Thanks!
 

Good thread! I am seriously thinking of buying a CZ21.
Coil size is whats keeping me from making an immediate purchase, I am guessing that the 8 inch would probably go deep enough and would handle trashy area betters. How much better I don't have a clue, I will be hunting in plowed ground where the remnants of an old sugar house is scattered.

Roy
 

If there is not much difference in trash separation between the two coils of the CZ21, I would opt for the larger.
 

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