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ProspectinInOz Questions

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13 years 1 month ago #1766 by Ismael
ProspectinInOz Questions was created by Ismael
A couple of posts have been asked about the claims that I made about the depth capabilities of the 2000 at lower frequencies. Rather than reply on that forum I have started this thread so we keep the mod discussions in the place of origin and so we don't need to go from one place to the other.

I could have replied on Dougs forum but to be quite honest I find the layout a pain in the arse when trying to read posts and also there is far too much politics and bad-mouthing there. That isn't to say it isn't a good forum just of late it is going the same way as Finders did...

Anyway back to the questions. Firstly:

douginpoz <konigslair@...> wrote:

Ismael this statement on your forum really grabbed my attention:"As it is I can say that Idoubt there is a detector in existence that will be able to see large DEEP targets that the 2000 running on low frequency will hear. As an example of this in the field with a coke/beer aluminum can with a 18" mono coil I can clearly hear it at shoulder hight!"
see:http://www.minelabmods.com/joomla/index.php?option=com_kunena&Itemid=49&func=view&catid=2&id
=1764#1764
Would you care to expand on this because as you know there are a number of us working on or want a Pi that will go much deeper on the big stuff than present offerings. How long do you think it might be before this low frequency mod becomes available? I presume also that the GB range will have to be expanded so that you do not "run" out of GB with the much longer Tx?
douginpoz


There isn't much to expand really, my shoulder height is approximately 59inches or 1.5 meters and I can hear the target well. Anything small (say 20gms or less) can be heard but the sensitivity is not there for the small stuff. So far I have found that different coils also contribute to some performance. As an example the 18" 2100 Kevlar coil is so far the best performer where as a slight degrading of performance in a modified dustbin lid 2000 coil (I pulled the coi out and molded it to a elliptical shape) but still only a little. A 24" UFO I made that outperforms the coiltek version was absolute crap! The 14" Coiltek DD could hear the can at around 80% of the height of my tests. As for running out of Ground Balance The only time that became an issue was with the smaller 10" joey and then only on Channel 2 as per the norm. I have set my VCO to go down to 930hz at the moment and will try that when I go out which at present I am trying to hold off until the Nemesis arrives hopefully this month but.... Getting back to the GB I had some issues in light mineralized soil that it was hard to find the exact point of balance and I mean a small turn of maybe 1/16th of a turn of the pot was the issue!!! The "bandwidth" was too large and needed a finer turning of the pot in channel 2, channel 1 was not so hard, but either way I was always within the center of the pot on most ground I tried it on.

Now Second question:

Two more questions:

1) How tall are you?, and


(the above is answered in the previous paragraph and to quantify it I am 5'9"

2) Can the detector discriminate between Fe/Non-Fe targets at that depth?

Allan


The 2000 has no discrimination but one thing that did have me a little puzzled was that I got a very small signal that had that "good" target sound and when I looked down it was a piece of old rusty metal around 2" x 4" and paper thin. I was going to bring it back as I had never had that happen except on small tacks and the like nothing that big. When I gotthe normal ferrous signal it was also of normal size such as pieces of wire or bully beef tins. The only noticeable thing was that I never got the normal side coil lobe problem that was halved at least. I mean if in normal frequency I went near a bully beef tin or lid I could hear it start at around a couple of feet whereas in the low freq that would be only 1 foot but raise the coil above it and it was triple at the very least.

As mentioned the low frequency is useless for anything other than large targets and I mean large I would say the rule of thumb would really be when you only want to look for targets that are .5 - 1oz or above and even then maybe bigger! Woody did his test against a 4000 with 1.25Mhz and apparently killed it on the test. A fellow mentioned (who is doing some other mods that I am not privy to but he is selling SD2000's with his additional mods at $8000 and has plenty of buyers! It also has the GPM as my mates put it in for him then he just played with it but this another day and thread) that woody sent him the 1.25 crystal to use and he reported not much if any difference. This could well be the case as I found many moons ago some odd frequencies and coil combinations make for xtals to be useless. To explain this better let's say you have a 2.8Mhz xtal it runs okay but using a vco go to say 2.855 and it is vastly different and quieter and more sensitive so being able to vary the frequency is definitely far superior than set xtals. BTW that 2.8 and 2.855 is just an example but something I did notice around 6 years ago when experimenting.

Well I hope that answers the questions and gives some insight into what I was saying. I don't believe that overall depth increases is the total solution otherwise just do the mods. I am with Dave and others that if you can maintain depth equal to a ML PI but not have any "Holes" and see all targets THAT is what should be the priority also discrimination without loss. That is why I
can't wait to get hold of the Nemesis. If it does perform as hoped then new "old" fields are just waiting for us...


Regards Ismael

:woohoo::woohoo::woohoo:
Regards Ismael

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13 years 1 month ago #1767 by Zed
Replied by Zed on topic ProspectinInOz Questions
G`day Ismael

I will be giving your detector a burn on the weekend,weather permitting.
Anything you might like me to try ?

Cheers Zed...

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13 years 1 month ago #1768 by Ismael
Replied by Ismael on topic ProspectinInOz Questions
Anything you like to mate, I will give you a call later...

:woohoo::woohoo::woohoo:
Regards Ismael

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13 years 3 weeks ago #1772 by ungar
Replied by ungar on topic ProspectinInOz Questions
G'day to all

I am new to this forum, but as "hard" relick hunter follow it always interested. Thank you for this forum.

I found a problem, what confused me:
Woody wrote/in prospectininoz Mmessage 8548/:"More mods are coming,like how to run your SD on24 Volts to get Mega Depth"

Ismael wrote /SD2000ModsDIY02March2008/:

"anything to do with changing the Transmit side of the 2000 is mostly waste of time.the exception iis only applying a higher voltage...but too much voltage will produce more noise and less performance"

Can anyone tell me what this is?
Sorry for bad english.

Regards Alex

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13 years 3 weeks ago #1773 by Zed
Replied by Zed on topic ProspectinInOz Questions
G`day Ungar
Welcome to the forum.

In a nut shell more coil current will equal more depth,there are a variety
of ways to do this,increasing the voltage to tha coil will drive more current into
the coil hence the 12v regulaters you see on the market.these will only increase
the voltage from 6v to 8.5v,depending on the regulater.
The idea of running a 2000 on 12v or 24v
sounds nice and clever but in reality its
very difficult to do,thats not to say it cant be done its just that a whole heap
of issues will need to be addressed which is what makes it difficult.For example the
fets will run very hot even at 12volts,the gain that you get and the trouble you have to go thru just does`nt make it a worth while idea,but still it can be fun trying.
Huge amounts of coil current can be nice but boy will those fets run dam hot.I have
run a 2000 on straight 12volts,it is doable but in my opinion the gains are marginal,but who knows maybe someone can do a better job of it than me.

Cheers Zed....

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13 years 3 weeks ago #1774 by ungar
Replied by ungar on topic ProspectinInOz Questions
Hi Zed,

thank you for quickly answer.

Alex

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