Another question

[Anonymous]

I see where they say the Explorer has 28 frequencies tht it uses, instead of 1 or 2. But somewhere else I read it just uses 11 of those. So which is right 28 or 11?
HH CPrunty

 

[Anonymous]

There are 28 frequencies with the highest and lowest fixed. The 28 frequencies can be shifted between the highest and lowest to give differences between the 28. Each shift is called a channel and they are 11 of them. We can think of this as 11 sets of the same 28 frequencies. FB S and BBS technology is going to by nature have noise problems so these shifts is to find the channel that is best for a given situation to reject external noise from soil minerals and stray RF. Failure to noise cancel appears to me to be the biggest problem with most users I have talked to or hunted with. When the Explorer starts to false it is a sure sign that we need to noise cancel.
I think the key to understanding multiple frequency is how the receiver and microprocessor deal with the fundamentals and harmonics. It is my opinion only that the value is based on how metals responds to different frequencies. Gold responds differently than silver, as an example, to low and high frequencies. If we probe these metals with different frequencies then compare the processed signals we can better ID the metal. This is based on basic non-destructive testing of metals that has been around a long time so there is really nothing new here. This is also how a slot machine tells a slug from a silver coin and coin some coin changes use this method. The difference is the soil matrix presents a more complex environment for the identification. I believe it is an advantage up to a point to have more variable to compare then it starts to muddy the process.
I believe the harmonics are very important to the ID of metals but has very little to do with depth. It is not very clear now many frequencies or harmonics are of value as some detector use 2 other 17, 28, and on up but no higher than about 100 for hobby detectors. I have used all of them so far and think I see a finer level of discrimination with more frequencies. However, it does not seem to me to make the difference in would I have found the coin or not. I have extensively tested the difference between 2 and 28 and it has not been a difference for me personally. I think that is because somewhere around 2.5khz for a lower frequency and 15khz for an upper frequency are the best for the coins and jewelry, gold and silver, we seek. Nugget detectors do better around 50khz as they can locate very tiny nuggets. A rule of thumb is the higher the frequency the smaller the target that can be located to a point. Frequencies that get above 50khz or so start to have problem in that they are attenuated and detect voids in the soil.
I can explain this in much greater detail but I don't think it ends up going anywhere. It is a little hard to see how harmonics and fundamental frequencies are used. A form of analysis called Fourier analysis is used to see the relationships and Fourier transform to look at the time domain and frequency domain of signals that have fundamentals and harmonics where amplitude and time are of interest.
In the end it comes down to a sine wave, square wave, rectangular wave all have harmonics and it depends on if they are used and how. The Explorer uses 28 with 11 shifts of the 28 for 11 noise cancel channels.
HH, Cody

 

[Anonymous]

Thank you Cody, that clears up, what I didn't understand. You mentioned 2.5 and 15khz as the probable best, I have a detector that has the 5 and 15, which I always found to work very good. But I believe the Explorer will do much better and be deeper. My old one is a real nickel machine, that was always what it did best. Of course if I didn't think the Explorer would do better, I wouldn't have paid all this money for it, as I'm not that well to do, that I can afford to waste money. Old too. Thanks again for your answer, I like to understand what is going on with the detector, it helps to be able to work with it better.
HH CPrunty

 

[Anonymous]

I should have been more clear in that if you think of about 2.5khz as best for high conductive metals such as silver and 15khz for lower conductive metals such as gold then some frequence in this range from will do a good job.
It is my understanding that the primary advantage of multiple frequency is the detector can be ground balanced to salt and iron oxides in the soil at the same time. All iron oxides give a negative phase in reference to pure ferrite while salts go a little positive. In the past you could ground balance to one or the other at any given point in time. By using at least two frequencies you can balance one to salt and the other to iron oxides and in some way balance the two for ground balance to both at the same time. After that it is a matter of several different signals to use for metal ID. This is just a brief summery of what we are told or I have read so one has to come to their own model of just what is going on. It is then a matter of does that model fit what happens in reality and then adjust the model so it does. I constructed my own model of how all this works and constantly adjust it here and there as I gain more knowledge and understading of how a detector works.
There are a lot of users that are very effective with a detector but have no idea how they work. I, as yourself, like to know what the detector is doing becasue it helps me to do better with the machine. That is just the tech type I am but I don't think that users that don't care for the technical side should become a tech type.
HH, Cody