60 ounces missed by ML4500 and 5000

Jonathan Porter wrote:I think you guys need to also think about 'Time constants', if a target loses its Eddie current before the switch on can receive it the detector will be blind to it. If you want to ignore mineralization you need to have the switch on time happen after the ground noise has dissipated; this is the true reason why some speci's fall into a PIs blind spot, the target signal dissipates away in around the same time frame as the ground signal does.

JP

Narrawa wrote:

......... I did this and this seemed to work well and then I found small pieces, one at 0.07g 3 inches down. whats your thought on using the higher range over the lower and what difference does frequency make?
thanks for the advice
Martin

Iv played with this over the years and have never been able to convince myself of any benefit from the hundreds/thousands of undug targets in which i tested it over. I think its more of a "feel good" setting, sure on  occasions the auto-tune may get it wrong, but to say the detector is able to hear nuggets from one tune decimal to the next would mean the detector has one hell of a flaw. Say for instance you never touch the manual tune, and only ever operate where the auto tune pulls up, could you be that unlucky it pulls up on a freq that nuggets dont signal on.?? Sounds corny doesn't it?...but thats whats being suggested.

I wouldn't get into the rut of thinking you must have it set on a certain number, or someone will come along and  burst your bubble and show you the error of your way. Iv seen it and the operator will put up with a detector thats as noisy as hell, rather than listen to reason because they believe without a doubt, its gospel.

The auto tune takes about 60sec to perform a function the inverter thought had merit. It takes time to write the program and factor in alot of what we dont understand about the regime. Id hazard a guess and say in the programing there is a set of Ones and Zeros thats factor in this very scenario and allow the detector full detection capabilities through the setting 0-255. While the number scale appears large, the frequency swing from memory is very small. A pointless function if it did discriminate on certain frequencies.  

At the end of the day....if you feel it makes you a better operator...let no one tell you different.


PS. When the auto tune function has been initiated, a detector in range is effected, this tells you the tx side of the function is also being shifted. Does the shifting tx freq return to its set value at the end of its cycle, or does it lock in with the rx.?  

Auto-tune works by listening to the background noise received by the coil over the range of possible frequencies and selecting the quietest one (during the short time the auto-tune takes.) It works well for man-made sources but doesn't work for random natural sources like solar activity.

thedigger wrote:
,made one out of pure silver wire,drawed it down to 0.15mm,18inches round,took 9 ounces of pure silver.

I hope this helps
Regards Thedigger

Guest wrote:

scotgold wrote:This thread could not have come at a better time for me.
I've been looking at the best detector to take on a short trip. I have two available either a White's Goldmaster 3 or a Minelab i-trak. The alternative is to rent one of the Minelab GPX models. Suggestions please?

Scotty,

The ML E-Track is a treasure hunting machine. It's not a prospecting machine as is the SD/GPX series or the Whites. Although the Whites, being a VLF is good for treasure hunting. How good the E-Track would handle the ubiqitious iron mineralisation in the WA Goldfields, I wouldn't know as I've never tried one out there. An E-Track wouldn't be my choice by a long way, unless I was in the local park looking for coins.

I'd go the GPX 5000 if cost isn't an issue but they do take some handling if you've never used one before. However, the ML manuals are very good and the factory pre-sets will get you 90% of the gold - if it's there. If the Whites comes to you at no cost and you can't go the hire of the GPX, I'd go the Whites, The Whites GM was "king of the hills" prior to the introduction of the ML SD series in 1994. The GPX is now top-dog but as I've pointed out here, it does miss gold. You might just find what the GPX misses.


Having said all this, I still reckon the GPX with it's Pulse Induction is the best there is currently.

HTH.

Cat