GPX4500....What is the maximum depth

Hi All and to respond JP
I'm still at a bit of a loss to understand whats going on with DDs and do feel they offer a depth benefit in mineralized ground over a mono ,but that has come from my own personal experience which I freely admit is not great as yours , I do understand what you and some others are saying and can see what is being said make sense but as I said before in practice it doesn't seem to work out that way for me.
Anyway this is a very interesting thread and I will be happy to sit back and read what others are saying and hopefully get a better understanding myself.
Great post Rob very informative
Regards Mark

MS wrote:Hi All and to respond JP
I'm still at a bit of a loss to understand whats going on with DDs and do feel they offer a depth benefit in mineralized ground over a mono ,but that has come from my own personal experience which I freely admit is not great as yours , I do understand what you and some others are saying and can see what is being said make sense but as I said before in practice it doesn't seem to work out that way for me.
Anyway this is a very interesting thread and I will be happy to sit back and read what others are saying and hopefully get a better understanding myself.
Great post Rob very informative
Regards Mark

Mark all I can say is; if you get the opportunity, try out a GPX-4500 in combination with a Monoloop coil and Enhance timings on ground you are familiar with with your GP 3500 and you will soon know exactly what the discussion is about . Robby_H has done a fantastic job of explaining the ins and outs of the differences between DD and Monoloop coils but it seems this is still not enough. It is very hard to sort the "wheat from the chaff" in cases like this due to the overriding belief system created and perpetuated when someone has success with a particular method, especially if the success was the "find of a life time". This perpetuation seems to be the sole basis of Marco's argument.

And Marco in every instance bar one all my large DEEP finds have been with a Monoloop coil, this is on nuggets ranging from 1 ounce right through to 83 ounces in goldfields ranging from WA to VIC through NSW and on up into QLD.

JP

Gday

There will always be too many variables in the way coils,detectors and people operate to set any hard and fast rules , every new machine I have owned I have tested as many coils as I could lay my hands on until I reach the point where I have about 4 coils, that cover my requirements for maximum sensitivity, weight, ground coverage,smoothness of operation, and of course depth, with trial and error I usually end up with about 4 coils that meet these requirements to my satisfaction.

I dont fool myself into thinking that I have the mix exactly right, but as I said I select these to meet my "satisfaction" that means that I have found sufficient gold with it to convince me that it is doing its job, but I have been about long enough to know that I am also leaving gold behind so I will always keep an open mind to the possibility of there being something better than what I have been using, so further trials are always necessary.

Some of the factors involved in the finding or missing of targets are things like the coil not being really suitable to the ground,or the machine, the way the machine has been set or tuned, the ability of the operator, the weather on the day, or very simply walking over the target from the wrong direction.....!

Anything from the condition of the operators hearing to the moisture content of the soil is a contributing factor to success or failure, so the arguement over this coil is better than that coil is flawed as all of these factors have to be considered, the best coils are the ones that work best for you, the one thats finding you the gold.

Arguements like these create a false hope for some operators as they often believe that they have to keep up with what the more experienced operators tell then in order for them to be successful, wrong, you just have to learn to use what you have and to recognise if the coils you are using are the most suitable to the detector you have, my point "trial and error".

I know for absolute certain that there are coils that WILL work better on one model of machine over another and even coils that will operate the same on two of the same model machines sometimes dont suit the operator, if the operator does not like the coil for any reason, maybe they prefer a round coil over an eliptical coil, as it does not suit their style of detecting or whatever, they will not build any confidence in that coil and will not be successful with it.

cheers

stayyerAU

Another point that should come into play here is that coils have changed over time. The latest machine are often followed closely by a new range of coils. I believe these coils are built to suit the latest machines with careful consideration to the upper and lower tolerances of these machines. I feel it may be a case of: If we develop a coil that works on the new model and as a side effect it happens to better an older model then its a bonus. I think that new coils are built for new machines and the two compliment each other. The outcome is a better all round result for the new detectors. Sensitive on more of the small bits and yet still punching down to the ultimate depth of the coil you happen to select for the job on the day. read the ground wrong and it wont matter what machine you are using. These machines (SD and above) basically all use the same technology yet picking the wrong coil will miss more gold than choice of machine. However, The latest machines have the ability to understand better, what the coil is seeing. I have no doubt that older machines could see the target but the audio response wasnt recognisable to the average Joe. The new models have refined the coils interpretation and have filtered out the unnecessary audio in an effort to make signals more friendly on the human ear.
I don't think its a question of depth however I do think its more of a case of being able to hear the target. Maybe the confusion comes from so many large finds being uncovered back in the SD days and by today's ratio of finds, the new technology doesn't even cast a shadow. Unfortunately prospecting is not like fishing, the ones we don't catch, don't go away and breed. Hence, once its gone its gone. A few thousand years of erosion will almost certainly bring those deeper ones to the surface. Who says this is not a hobby for the future
Brett.

Hi All
I went to a Coiltek Seminar about 5 year ago.A guy called Jimmy Stewart (Owner of the Laancoorie Park)He gave a talk on Geology,Reef Lines Indicators etc.Hes quite an incredable guy.He'd built coils that about 6 foot in diameter and contraputions to carry them.He eventualy got around to how coils and minelab machines work.From what I can remember I goes like this.Our Machines transmit High Med and Low Frequencies.From the info we got from an Alcemist Post I believe there called Pulse Trains.These are being transmitted a an incrediaby fast rate could be 100's per millisecond.So If we Use the letter H for High freqs M for Med and L for low.Here is a sample pulse train

LLLLLLLLLLLLLLMMMMMHH we will call this one Sd2200

LLLLLLLLLMMMMMMHHHHH we will call this one GP3000

LLLLLLMMMMMMHHHHHHH we will call this one Gpx4000

So our machines transmit create an eddy current in the nugget and then recieve and I gather its timings that determine what is recieved back.
Jimmy got on to topic of "Gold Signature" and said that there was no new electronics and all you could is alter the array of frequencies or timings.
From this I take it that say you had a detector that had a pulse train of MMMMMMHHHHH and you passed it over a 40 ouncer at 1 Metre and and the timings recieve was set for High and Medium freqs then it would not be recognised.
The above pulse trains are not actual pulse trains but only a representation.As we know there are nuggets that because of the size and depth any machine with the right coil combination will get.And nuggets out there that are invisible because I believe the Pulse Train and Timings and coil size is not suited to it.Im not a tecky guys and have only posted this because since that seminar in which Jimmy spoke and Achemist putting a name to pulse trains I have not heard one word that explains the difference in design of our Machines.I know there is more in the area of nulls and my explanation of transmit and recieve can be bettered.Hopefully so someone else will come onboard and explain it better.I also know that the newer machines run monos better but the 5000 6000 and 7000 will come along.Perhaps they will inform us what bais it has been designed for MED SHALLOW or DEEP NUGGS Only in gold my friends and pigs will fly
Cheers Dig

Hi all - fresh back from JP country (clermont) sorry JP have cleaned out one of your patches. (but guess you didnt know about this patch or they wouldnt still be there).
in mcmasters paddock, with ironstone on every nugget, scored many 18g to 79g nuggets. down from 18" to 21"
4500 running with a 17x12 NF super light mono, in enhance, deep, inverted, gain 6-8, stabliser 7. only difference to your settings jp is the audio tone at 88, yes thats right 88. and yes i was in DD with the fourth swith and not mono, as you do jp and stated in your seta DVD (thanks for the tip - it works) found it gives a very distinct sharp response to deep targets, very obviously different to ground noises, sounds like a sweet half grammer down a few inches.
my new chum mate, three days into detecting, latched onto the 79g and was down 24 plus inches(half way to china)when i came upon him, he had missed the target by nine inches. broken another golden rule showing him how to tell he had missed it by putting my machine in CANCEL, sticking the upended eliptical coil down his whopping hole, and showing how there was a slight noise in one side of the hole down 18 inches.(sorry, another golden rule gone west).
now for all you people who reckon enhence doesnt go deep enough get this ---- he found it with one of those new iridiscent green waterproof 12" mono coils (i personally dont know the name of that coil, but all the fellas at clermont were rubbishing them).
my best and biggest in that very hot ground of red soil with anthills and burnt anthill soil was 28.4g down 21" very obvious to hear and only reason it was still there is it was under a sardine tin (jp, you probably know who the sardine tin culprit is) yous truly picked up that tin and got the prize, right beside where they parken the car. DECIDED TO DETECT THE OTHER SIDE OF THE CAR AND SURE ENOUGH TWO MORE SARDINE TINS WITH LIDS AND UNDER THEM ANOTHER 18GRAMMER, 1.7g and 6g ---- no bullshit ----
might add that one anthill had a very clear 1g down a few inches on one side, and down 18" on the other side a 22g piece. i had previously done this area with the gpextreme about six years back and believe me i REMEMBER THAT ANTHILL it had a strange ground noise about it, but wasnt worth digging. with the 4500, no problems hearing it. had to come home as i was finding a big nugget at sunup each day and that was buggering me for the rest of the day, what a problem we all have.
if they ever come up with quietening down the general , normal ,mode, look out as it is extremely powerful and yes i tested it on some of those deep targets and it fairly screemed at me, but then so did all the rest of that country, couldnt move 6 inches without target noises, tested a few by going down 6inches or so and trying enhance but there still was nothing there, went down 12 inches with one but it was only ground noise.
moral of the story, fish for the big ones and you will find them. fish for the small ones and thats all you will get
havent learnt how to post the pictures yet, working on it. boy what a trip, what a machine total of eleven ounces in those 20 detecting days. .... kev

Congratulations Kev, makes it all worth while.

Thanks for the details as well - it was a good read

Jeff