CS4pi

[Nauti]

They have had over 25 years to waterproof the control box......its a very old design,not a new detector.It's like their 1220xd,a none motion machine that has been in production for 30+ years and still sells well.....i have one.
The 4 has its roots in Eric Fosters pi designs,i'm sure that has something to do with its "supposed" excellent performance.I suppose that while it still sells well they don't think it necessary to improve it??

 

[Sand Sifter]

They have had over 25 years to waterproof the control box......its a very old design,not a new detector.It's like their 1220xd,a none motion machine that has been in production for 30+ years and still sells well.....i have one.
The 4 has its roots in Eric Fosters pi designs,i'm sure that has something to do with its "supposed" excellent performance.I suppose that while it still sells well they don't think it necessary to improve it??

Seems a lot of the older PI's were based on Eric Fosters designs, that man left his fingerprints on a lot of different detectors, lol. I am by no means qualified to judge or evaluate PI designs, just got my first PI last year after 56 years swinging BBS/SMF, VLF, TR, and BFO detectors, but from what I've seen and have heard, PI circuits tend to be fairly simple, smaller and less complicated than today's modern SMF digital detectors, at least for the White's Surfmaster PI series. My Dual Field has 3 control knobs, the previous PI versions only had 2 control knobs to adjust, so a fairly simple circuit. After the Dual Field, White's released the BeachHunter PI, which has a larger control box, with about 5 or 6 control knobs, and from what I've read, it's basically a TDI SL put into a waterproof enclosure. So, I figure the circuit for the BH is probably more complicated than my Dual Field since it has more adjustment possibilities, but still probably simpler than today's digital circuits.

I hope to learn a lot more about PI's as my wife got me Carl Mooreland's "Inside the Metal Detector" 3rd edition book for Christmas. Carl is a master/genius PI designer and was involved in the design of White's Surfmaster PI's as well as the TDI SL I believe. The book is large with 612 pages, so I'm sure it's going to melt my brain. Carl's probably forgotten more about detector circuits than most of us will ever know, lol.

Just for grins, I posted a capture of my Dual Fields control box. You can see that the box itself isn't that big. I just measured mine and it's 4" wide by 6 & 1/2" long. As you can see in the pic, after removing the top lid, 1/2 of the area inside the box is for the batteries, leaving the other half of the box for the pcb. Based on the size of 4"x6.5", that would only allow a maximum of 4"x3.25" for the pcb, but more likely a bit less than that to allow for the thickness of the box, room to position the pcb and to run wires, etc., so the pcb is probably very small. The pcb is covered so I'm not going to mess with it, but I'd love to take a look at the circuit board. There can't be that many analog components on that small of a pcb, so I assume that the circuit of my Dual Field probably isn't that complex, compared to today's detectors & electronics.

 

[Nauti]

Wow,612 pages about simple pi circuits.......there must be more to them than we thought..
The control box on the 4 is small and as you know only has two control knobs,the sensitivity and pulse control.......its so easy to set up and cscope probably think thats all anybody needs to get great results.......to be fair it probably is.There is a daft little light that lights up when you go over a target but its totally useless as you can't really see it in daylight,maybe cscope thought adding that would make the detector more appealing .
What sort of depths are you getting with the dual field on coins etc......might be interesting in comparing it to the 4 when i get it back and have learned it properly.

 

[Odanscoils]

Seems a lot of the older PI's were based on Eric Fosters designs, that man left his fingerprints on a lot of different detectors, lol. I am by no means qualified to judge or evaluate PI designs, just got my first PI last year after 56 years swinging BBS/SMF, VLF, TR, and BFO detectors, but from what I've seen and have heard, PI circuits tend to be fairly simple, smaller and less complicated than today's modern SMF digital detectors, at least for the White's Surfmaster PI series. My Dual Field has 3 control knobs, the previous PI versions only had 2 control knobs to adjust, so a fairly simple circuit. After the Dual Field, White's released the BeachHunter PI, which has a larger control box, with about 5 or 6 control knobs, and from what I've read, it's basically a TDI SL put into a waterproof enclosure. So, I figure the circuit for the BH is probably more complicated than my Dual Field since it has more adjustment possibilities, but still probably simpler than today's digital circuits.

I hope to learn a lot more about PI's as my wife got me Carl Mooreland's "Inside the Metal Detector" 3rd edition book for Christmas. Carl is a master/genius PI designer and was involved in the design of White's Surfmaster PI's as well as the TDI SL I believe. The book is large with 612 pages, so I'm sure it's going to melt my brain. Carl's probably forgotten more about detector circuits than most of us will ever know, lol.

Just for grins, I posted a capture of my Dual Fields control box. You can see that the box itself isn't that big. I just measured mine and it's 4" wide by 6 & 1/2" long. As you can see in the pic, after removing the top lid, 1/2 of the area inside the box is for the batteries, leaving the other half of the box for the pcb. Based on the size of 4"x6.5", that would only allow a maximum of 4"x3.25" for the pcb, but more likely a bit less than that to allow for the thickness of the box, room to position the pcb and to run wires, etc., so the pcb is probably very small. The pcb is covered so I'm not going to mess with it, but I'd love to take a look at the circuit board. There can't be that many analog components on that small of a pcb, so I assume that the circuit of my Dual Field probably isn't that complex, compared to today's detectors & electronics.

View attachment 84770

Picked up that book myself.
Still thumbing thru.
Interesting reading.
Though gets a little technical.

 

[Sand Sifter]

Wow,612 pages about simple pi circuits.......there must be more to them than we thought..
The control box on the 4 is small and as you know only has two control knobs,the sensitivity and pulse control.......its so easy to set up and cscope probably think thats all anybody needs to get great results.......to be fair it probably is.There is a daft little light that lights up when you go over a target but its totally useless as you can't really see it in daylight,maybe cscope thought adding that would make the detector more appealing .
What sort of depths are you getting with the dual field on coins etc......might be interesting in comparing it to the 4 when i get it back and have learned it properly.

It's not just about PI's; it covers all metal detector technology from the beginning. There's chapters on BFO detectors, TR's, VLF's, PI's, Multifrequency, coils, just about everything you'd want to know/learn about detectors. I started with a BFO Heathkit back around 69', then upgraded to a White's Coinmaster IV TR in 71', then moved to VLF's, BBS/SMF, and finally got myself a PI last year. It's a pretty technical book, so sometimes, I need to re-read paragraphs, but he does include a lot of drawings, charts, schematics, etc., to help explain things visually.

I've only had the Dual Field out 4 times so far, and the last time was when I was really sick when I hunted for 2 days after a nor'easter. I could only last 3 hours on day 1, and 2 hours on the 2nd day. But on that 2nd day, I found a coin line in the wet and worked that to the right side until it ran out, then turned around and worked the same line to the left side of the wet. Found more coins and a Sterling Silver .925 ring with stones all the way around. They're very small, look like diamonds, so probably either chips or fakes, I guess. I haven't tested the stones, so can't say either way, but I was so sick when I found it, it was still a big thrill. IIRC, I think I dug 2 or 3 scoopfuls to get it, along with the coins. So, I'd estimate depth somewhere in the 10" - 15" range.

 

[Odanscoils]

It's not just about PI's; it covers all metal detector technology from the beginning. There's chapters on BFO detectors, TR's, VLF's, PI's, Multifrequency, coils, just about everything you'd want to know/learn about detectors. I started with a BFO Heathkit back around 69', then upgraded to a White's Coinmaster IV TR in 71', then moved to VLF's, BBS/SMF, and finally got myself a PI last year. It's a pretty technical book, so sometimes, I need to re-read paragraphs, but he does include a lot of drawings, charts, schematics, etc., to help explain things visually.

I've only had the Dual Field out 4 times so far, and the last time was when I was really sick when I hunted for 2 days after a nor'easter. I could only last 3 hours on day 1, and 2 hours on the 2nd day. But on that 2nd day, I found a coin line in the wet and worked that to the right side until it ran out, then turned around and worked the same line to the left side of the wet. Found more coins and a Sterling Silver .925 ring with stones all the way around. They're very small, look like diamonds, so probably either chips or fakes, I guess. I haven't tested the stones, so can't say either way, but I was so sick when I found it, it was still a big thrill. IIRC, I think I dug 2 or 3 scoopfuls to get it, along with the coins. So, I'd estimate depth somewhere in the 10" - 15" range.

View attachment 84820

View attachment 84821

Sweet.
Haven't found a line in quite awhile.

 

[Nauti]

It's not just about PI's; it covers all metal detector technology from the beginning. There's chapters on BFO detectors, TR's, VLF's, PI's, Multifrequency, coils, just about everything you'd want to know/learn about detectors. I started with a BFO Heathkit back around 69', then upgraded to a White's Coinmaster IV TR in 71', then moved to VLF's, BBS/SMF, and finally got myself a PI last year. It's a pretty technical book, so sometimes, I need to re-read paragraphs, but he does include a lot of drawings, charts, schematics, etc., to help explain things visually.

I've only had the Dual Field out 4 times so far, and the last time was when I was really sick when I hunted for 2 days after a nor'easter. I could only last 3 hours on day 1, and 2 hours on the 2nd day. But on that 2nd day, I found a coin line in the wet and worked that to the right side until it ran out, then turned around and worked the same line to the left side of the wet. Found more coins and a Sterling Silver .925 ring with stones all the way around. They're very small, look like diamonds, so probably either chips or fakes, I guess. I haven't tested the stones, so can't say either way, but I was so sick when I found it, it was still a big thrill. IIRC, I think I dug 2 or 3 scoopfuls to get it, along with the coins. So, I'd estimate depth somewhere in the 10" - 15" range.

View attachment 84820

View attachment 84821

Sounds like a great read.Sounds like your pi is working really well,hope the 4 gives me the same sort of depths.That ring is a little beauty........seeing stuff like that makes me want to get on the beach all the more,can't wait to get my pi back.

 

[LawrencetheMDer]

Thanks, just ordered Carl Mooreland's "Inside the Metal Detector" 3rd edition. Been looking for an updated book to better understand the inside of a metal detector and Mooreland's fits the bill.