Greetings to everyone,
It has been a long time since I have been on this forum. I have however, been busy and not idle. Quite some time ago I took on an educational project for myself. I decided to build a PI detector to better understand the technology and it's critical characteristics. Being a retired engineer and having been metal detecting since the late 60s and I have designed and built detectors of various types but never a PI machine. I spent several months researching as much information on the subject as I could find. I studied every circuit that I could get my hands on, circuits from Eric Foster, Carl Moreland, and other commercial circuits when ever I could get them. Anyway, I have been field testing my detector for the last 6 month and while it is not competitive with the top of the line machines on the market, I think it performs equal to or better than the average PI machine on the market. I want to say that during the development process, Reg Sniff provided a wealth of insight and technical information on PI technology, especially in the area of small gold detection.
I have attached several pictures. The one of the detector show it with an 8" mono coil installed and an 10" coil sitting on the floor. The picture of the pile of money is just to show that it is capable of finding coins with no trouble. The picture of the rings and nuggets give you a little indication of its capability in on the beach and in the gold field. The small 10K baby ring was found in a volley ball court and the mans 14 K gold ring was found on a swimming beach. Both of the gold nuggets were found down against bed rock. The largest one is about a gram and was found about 6" deep in a pocket in the bed rock and the smaller one is about 7 grains and it was about 3" deep in a bed rock crack on edge. The detector will detect a 5 grain nugget at about 3" in air and a 3 grain nugget at about 1 1/2" using the 8" coil. The larger of the two nuggets found produced a very good signal. The smaller one was weaker but still very clear. The dime is just for relative size comparison. The ground where I live has a fair amount of mineralization in it and the detector handles the bad ground very well.
Anyway, I am satisfied with the detectors performance and it has been a very useful project to keep this old mans mind working on all cylinders.
God Bless to all and HH.
Smitty II
It has been a long time since I have been on this forum. I have however, been busy and not idle. Quite some time ago I took on an educational project for myself. I decided to build a PI detector to better understand the technology and it's critical characteristics. Being a retired engineer and having been metal detecting since the late 60s and I have designed and built detectors of various types but never a PI machine. I spent several months researching as much information on the subject as I could find. I studied every circuit that I could get my hands on, circuits from Eric Foster, Carl Moreland, and other commercial circuits when ever I could get them. Anyway, I have been field testing my detector for the last 6 month and while it is not competitive with the top of the line machines on the market, I think it performs equal to or better than the average PI machine on the market. I want to say that during the development process, Reg Sniff provided a wealth of insight and technical information on PI technology, especially in the area of small gold detection.
I have attached several pictures. The one of the detector show it with an 8" mono coil installed and an 10" coil sitting on the floor. The picture of the pile of money is just to show that it is capable of finding coins with no trouble. The picture of the rings and nuggets give you a little indication of its capability in on the beach and in the gold field. The small 10K baby ring was found in a volley ball court and the mans 14 K gold ring was found on a swimming beach. Both of the gold nuggets were found down against bed rock. The largest one is about a gram and was found about 6" deep in a pocket in the bed rock and the smaller one is about 7 grains and it was about 3" deep in a bed rock crack on edge. The detector will detect a 5 grain nugget at about 3" in air and a 3 grain nugget at about 1 1/2" using the 8" coil. The larger of the two nuggets found produced a very good signal. The smaller one was weaker but still very clear. The dime is just for relative size comparison. The ground where I live has a fair amount of mineralization in it and the detector handles the bad ground very well.
Anyway, I am satisfied with the detectors performance and it has been a very useful project to keep this old mans mind working on all cylinders.
God Bless to all and HH.
Smitty II