I'm new on this forum and like Alexandre Tartar, I live in north of France.
I was a young prospector in the 90's and asked my father (electronic engineer with good knowledge in magnetic field theory) to build a PI to hunt the beaches. So we have made, in a few months, an home-made PI metal detector 25 years ago, based on the technology of the old White's Surfmaster PI (mono coil). I remember the use of FETs (Field Effects Transistors to make 200 volts pulses). It worked, but unfortunately, my father was afraid by a so powerful magnetic fields and has continued his research on VLF detectors, until today !
After this short presentation, here's my question :
Is the Impulse AQ a bipolar detector ?
Le Jag has explained us on the french forum "detecteur.net" this technology developped by Alexandre :
Positive and Negative pulse are alternatively sent.
The positive one light the gold ring but magnetize the soil.
The negative one demagnetize the soil.
What about it ?
By ALEXANDRE TARTAR
HOW MAKE A SERIOUS COMPARATIVE TESTS PROCEDURE
First rule Blind tests are mandatory to be serious.
Second rule if you do not agree refer to rule number 1 😊
The purpose of this playground, and not to take into account the feeling of the prospector. It is too easy for a participant to indicate that he is correctly detecting the target. But in general he does not detect it or he thinks to detect it. It often detects a ground effect.
During our long experience and our meetings with prospectors at the beach, we realized that the prospector was often influenced by the pride placed in his detector. This is why we have implemented this drastic and non-falsifiable comparative tests procedure.
Of course for this test you have to be 2 people.
A person who hides targets and a person who tries to find them. The depth tests can be done simultaneously.
It is obvious that here are static tests. The reality is even more difficult! See for yourself the catastrophic results ....
Document here :
COMPARATIVE TESTS PROCEDURE.pdf
A few afternoons back I went out to a local beach to do my normal searching. It has been a time of few waves and even fewer targets. Everyone hears this from me quite often but I've heard it from other detectorists as well. So, you relax, go slow and just enjoy the beach.
A bit down from me I saw a group along the blanket line and there was something different. There was a little kid (older than mine) about 5 or so swinging a metal detector. It had a kinda orange coil and the kid just was playing with it a bit and then running around with the other kids. I decided to go up with my 800 in hand and have a little chat with him and maybe 'show' him how to find things. By the time I got up to where he was he was out near the water and the only one still around was his dad and his dad's friend or brother.
We started up a bit of a chat and they said they had bought the detector off of Amazon for $60. I didn't recognize it but it was giving my 800 an EMI fit so I went to a different channel. I told them what I had in mind (quarter in hand) and they called the little boy over. I wish I had taken a picture of the detector but it was a short arm, adjustable with compression fittings, concentric coil detector of a brand I didn't catch. It had a screen that was discriminating and it did 'find' the planted quarter which the kid liked but didn't have that much interest in it.
One of the really interesting parts of the story was the friend. He told me it was an Amazon purchase and thought that $60 should make it a very good detector. They didn't really have a clue. They asked me about mine and I told them and I could see their jaws drop a bit on now knowing that 'pros' like me were out with detectors from $500 to $900! It was way out side of their conception so they asked me what did I think of their detector. I didn't really pick it up but I told them there are these new little detectors that could be better than a lot of the detectors just 5 to 8 years old that sold for much, much higher prices.
This is part of the new purchaser and market for the detector companies which provide higher end products like Minelab. It is a new reality of buyer and probably the reason for their low end detectors.
When I came back and searched Amazon looking for this $60 detector I was flooded with many, many detectors from companies unknown. Minelab is not on Amazon it seems and many other searches for the average buyer. Some of you here see some advertising on this forum for the best metal detectors. I started a thread about it a couple of weeks back.
One thing I did happen across when looking for the metal detectors were a few 'board detectors.' These were complete metal detectors on a circuit board that sell for less than $5.00! It becomes more clear that these detector circuit boards placed in a molded plastic handle become the brains for a $50.00 detector that wholesales for maybe $26. Components are cheap.
Marketing and R&D are expensive!
I didn't find much on the beach that day but I brightened the face of a little kid and I got a good story.
The GB knob on my Tejon is super loose now after the tons of hours I put on it and I get a little waver in the threshold. Trying to find who sells damping grease in really small quantities as the stuff is horribly expensive. Mcmaster has some at $111 + shipping, Amazon has some in the $30 range and all more expensive than the potentiometer itself. I could replace it but rather not start soldering in parts if I don't have to.
Just curious, has anyone tried lowering the tone break T1 to negative numbers or all the way down to -9 on your hunts? Is it worth it, did anything good come out? Or is it just a recipe for headache?
Reason being, I was playing yesterday with the coil and found an old button that is clearly non-ferrous, but gives negative TID in multi-frequency and positive/negative on some single freqs.