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Goldquest SS v Western Australian Ironstone

A

Anonymous

Guest
I bought my Goldquest primarily for water/beach hunting but having some of the best goldfields only 6 hours drive from here (I live in Perth),I thought I'd do a test.
I have a gravel pathway down the side of my house, it comprises of heavy ironstone gravel (a bit like small dark red/purple marbles). This ground could easily be considered as extemely "bad" ground to work on. The individual pieces jump up onto a decent magnet. Eric knows what I mean when I talk about this ground.
My test was to place a 18k wedding band under all of this material (about 5" deep) and see if it could be detected.
My initial settings were DELAY at about 15uS and SAT at about 9 o'clock. The result was a screaming detector that gave me an absolute blast.
I began to think the detector would be inoperable in these extreme conditions. For the fun of it, I increased the SAT to fast and DELAY to about 50uS and waved the coil about 4" off the gravel surface....the result was a clear and unmistakable target sound, I was impressed. I then removed the ring, scanned, and the signal was gone.
The bottom line was the detector could detect the presence of a ring sized target 5" under probably the worst ground matrix possible with the settings described and the coil well off the surface (crucial).
I believe that too be a noteworthy performance on targets approaching that size and in those conditions.
Anyhow, back to the beach...it's low tide.
Tony.
 
Tony,
What was the fastest delay speed you were able to use there ?
I read you set it to 50uS. Did you try it say at 40uS., 30uS. ???
Mr. Bill
 
Hi Tony,
I hope your not the guy "cleaning up" on all these beaches around here of late in Perth.
If you are, well, you've been doing a bloody good job of it and all I can say is "Good on ya" <IMG SRC="/forums/images/biggrin.gif" BORDER=0 ALT=":D">
Do you hunt any beach in particular here in Perth?
If you don't mind I'd like to meet up and see the GOLDQUEST SS in action and mostly out of curiousity.
Or else maybe we just might meet up by chance on one of the local beaches around here during the winter hunts. Maybe you know, one of those days when you can't see a soul for miles either way up or down the beach and you might be the only one out there...........metal detecing.
You might even know some of the other blokes that I sometimes detect with.
Send me an email as I can't send you one due to it not being published here.
Hardnose
in a suburb of Perth
West Australia.
 
Hi Tony,
I really appreciate your taking the time to run the test you did.
You have reinforced a couple of things that I have mentioned several times in earlier posts. Those points are that one can raise the coil and increase the SAT speed to compensate for really bad ground.
Ground signals, by nature reduce much more than target signals with coil separation between the two, meaning that just raising the coil will cause a greater reduction of ground signal than target signal.
I hope you will continue with your experiments and post the results. I would expect you will find different SAT/Delay/coil height combinations that will allow the use of the GQ in areas where one might think it wouldn't work.
Thanks again,
Reg
 
Hi Tony,
Interesting test. If the ring was under 5in of gravel and the coil 4in above, this is a total range of 9in for a certain audio level. Can you measure the range in air at the same settings and for the same audio level. The reason I ask, is that the highly magnetic gravel seems to cause horizontal spreading of the transmitter field from the coil resulting in considerably less range when the target is buried. Even the Minelab SD detectors are often unable to detect reasonable size nuggets that are more than 6 - 8in deep because of this effect. One prospector in Kalgoorlie reported that more nuggets were detected after 6in of dirt was scraped off the surface of his patch. The new nuggets would have easily been detected at their depth, were it not for the mineralised ground.
What is the effect of turning the threshold control back to reduce the effect of the ground? i.e. to get the coil closer to it before the audio rises.
Eric.
 
Hi Hardnose,
I hope he is the guy <IMG SRC="/forums/images/smile.gif" BORDER=0 ALT=":)"> Good publicity for the Goldquest.
Eric.
 
Eric,
Yes, that sounds like Chris Hake.
The measurements I have given are accurate.
A couple of things that I know are:
1) The Goldquest SS can pretty well match an SD2000 in depth on a neutral ground matrix (i.e dry beach sand or even wet beach sand). This is with my settings at minimum DELAY and slow SAT, and with the threshold almost silent.
2) The gravel bed that I detected on comprises loose gravel pieces, and is not compressed/compacted with any bad soil or clay material as one might expect on the goldfields....could this have an affect on ground noise one way or another. My pathway is still a fairly dense layer of ironstone. I'm aware of claypans (very dense) being unworkable....no gaps for the Tx field to sneak through (??)
3) Yes, turning back the threshold to an initial "just silent" starting point also minimises any unwanted audio feedback.
I think one of your questions is an air test for the ring.....is this with settings at minimum DELAY and SAT at slow, or settings as per the gravel test bed?
Tony.
 
Reg,
I completely agree !!
I was quite surprised at the results I got.
I have used an SD2000 in areas only by raising the coil some distance off the ground, it can be anywhere from 2" to as much as 8" (you will get the big pieces). There is a need to maintain an consistent height off the ground (whatever this may be), and I did this by securing the coil and stem with a fixed length off strapping from a body harness. This takes all of the weight as well as ensuring a pre-set sweep height off the ground.
I will no doubt play around with other settings, even though prospecting is something I haven't done in some years.
Tony.
 
Hardnose (that's a familiar name on Finders if I recall),
I don't do much dry beach hunting. My areas are nearly always the high tide mark and out to about shoulder deep water.
There is some one from a northern suburb who does a fair bit of beach hunting with an SD2000, but he don't scare me! He might be the one vacuuming the beaches...he should be out 600kms to the East.
I'll send you an email shortly. No worries about meeting up somewhere.
The Goldquest SS is a top performer. It suits me perfectly because I want maximum depth and I dig all targets in the water as there isn't much junk to be found. I know one thing, if you hunt behind me and my GQ, you will always have a straight back!
Tony.
 
....sometimes I do wander up on the dry beach if any of my toothy friends are spotted....so yes, I have cleaned up a few beaches <IMG SRC="/forums/images/smile.gif" BORDER=0 ALT=":)">
 
Bill,
I have "decreased" the DELAY, but I found that 40uS was about the limit....I'll play around some more...you never know.
Tony.
 
Hi Tony,
You brought up a good point that hasn't been mentioned before and that is the delay can be increased to minimize the ground signals.
Yes, by increasing the delay one will miss small gold, but it can greatly reduce really bad ground signals and allow the detection of larger gold nuggets such as those found in Australia.
Most of all, your post has presented a different opinion on the use of all the controls to compensate for the extreme external environment you have in Australia. I have been curious to hear how the detector would work over there.
Hopefully, this discussion will get other GQ owners to experiment more with all the controls. I think people will find the detector is more versatile than they realize.
Reg
 
Reg,
You are definitely right....when I'm hunting for small jewellery items, then I use the DELAY sparingly. I'll not go past 15uS, even if there is some saltwater interference. I'm sure there are a lot of PI users who set the DELAY too far clockwise in the wet sand/water because they are scared of a little background noise...target signals stand out clearly and are hard to miss. It's a fine line between detecting a nice gold ring and missing it completely because the DELAY has been tweaked just a fraction too high. I'm glad I discovered this during the early days and not after a couple of years.
You can stub your toe on some of the nuggets that still turn up in the desert areas over here. I'd be more than happy to operate the GQ with the DELAY approaching 40-50uS knowing the smaller nuggets may be missed.
These two different hunting environments clearly illustrate the GQ's flexibility. It's very easy to get locked into certain settings, only to find you have never got into top gear. For just 3 pots, there are numerous combined settings that will optimise the performance (no doubt, you are probably aware of all of this more than anyone).
Tony.
 
Hi Reg and Tony,
I can see a need for me to do some tests here, with my box of Australian ironstone. Increasing the delay also increases the width of the TX pulse, sample pulses and sample pulse separation. For example, the TX width increases from 30uS at the highest frequency to 120uS at the lowest. I will couple up a chart recorder to the receiver and with the coil at a fixed height above the ironstone, see what happens to the strength of the signal. Then put a ring under the ironstone and look at the total signal is like at different frequencies. What we want to find is the point where the ring/ironstone ratio is a maximum.
Eric.
 
Hi Tony,
Yes, Chris Hake is the man. I have had a wealth of good data from him regarding prospecting techniques in WA goldfields.
The effect of ironstone, whether it is compacted or not, whether wet or dry seems a very complex subject and there are many unanswered questions. Wet ironstone ground seems to be quieter than dry. Why, I don't know.
The air test that I thought would be useful, is with the same settings as you ended up with on the gravel.
I haven't forgotten about the information I was going to email you. Its just that I have been in Abingdon for the past few days and all my board diagrams etc are in Brixham; 180 miles away. I will be back there by Monday and will attend to it.
Eric.
 
Eric,
I've often wondered whether a more solid ground matrix can become more of a problem. I know that many prospectors will revisit goldfield areas after some decent rain, which out there, isn't all that regular. They benefit from quieter "bad" ground and better penetration.
I will do an air test (accurate) with settings as per the gravel test bed. I will post test results with the detector configured for max depth as well.
No rush for the detector tone alteration details.
Tony.
 
You will never clean up a beach my friend.
Regards
kris in Vic.
 
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