Iron Discrimination With GPX

[Twapster]

Ok making some good sense guys, really appreciate the info and im sure this thread will also answer the question for others "thinking the same thing".

I think Gypsy has given a good insight into why answers like Redfins are the norm, it has been very difficult to research WHY, I try not to make it a habit of believing more experienced detectorists if there is no explanation. Like when someone says "that model is no good"....or the old "no gold here folks"......

I now have an answer that makes sense. Im sure there will be others with different opinion, all opinions welcome!

 

[Heatho]

Using a DD coil on certain very noisy ground types or in EMI affected areas should not be discounted either, sometimes you'll get better performance than with a mono. Using a mono with some timings would be near impossible on the goldfields.

I don't use discrimination on my 5000 as I mainly run mono's but it's good to have the option if wanted or needed. Though next time out I'm going to use a DD so I can use some deeper timings like Normal, Sharp or Sensitive Extra and have the option to switch on the discrim if I want.

Try the discriminator Twapster, that is the only way to see if it suits you. I'd detect without it and only switch it on after I have discovered a target, then in 99% of cases I'd still dig the target if it was blanking.

 

[Twapster]

Thanks Heatho, ive dug my fair share of Iron Clunkers, while I love to dig there are occasions where i've wasted a good 20 mins and near exhausted myself digging a half horse shoe. A VLF would have probably told me it was a horse shoe, and if there was a nugget under it i't would also tell me that. With a PI not so easy hence my research on why iron reject is a function on the GPX, yet rarely endorsed.

 

[Heatho]

Thanks Heatho, ive dug my fair share of Iron Clunkers, while I love to dig there are occasions where i've wasted a good 20 mins and near exhausted myself digging a half horse shoe. A VLF would have probably told me it was a horse shoe, and if there was a nugget under it i't would also tell me that. With a PI not so easy hence my research on why iron reject is a function on the GPX, yet rarely endorsed.

Mate, gold detecting is hard work, there is no easy way and digging trash is just all part of the game. I don't honestly think there is a detector on the planet that will let you know if there is a nug under a horse shoe, even the best VLF won't help you there. Wasting time digging junk like this is just the way it goes, some days you get lucky other days are just filled with junk. Patience and methodical detecting is what's required, the people who put in that little bit extra are the ones who get a golden reward.

Sometimes you need to get rid of the junk before the gold is revealed. To be honest I've found bugger all gold, I've got a bit but not much, though I've dug enough junk to know that my reward is coming and will be when I least expect it....... lol. I've been gold detecting enough to see others get some nice little bits too and it will be my turn sooner or later, though it is frustrating you need to persevere and have a break when when about to pack it in, then after the break, continue on.

Remember that it's just like fishing......

 

[Twapster]

Yep I can fish all day, not get a bite and still enjoy it all!!

 

[old hand]

DD coils have their places in junk spots nears fences and electric fences run in cancel and the same for under power lines just take your time you will find the best modes that suits where you are working,its not very often I use a DD coil but when you think about it all the early PI were using DD coils regards john

 

[Picker]

Im finding since using a gpx im digging loads of junk at extreme depths its becoming off putting spending all the detecting time digging trash. Will give the dd a go in discrim and hope for less junk next time. Have filled up a bucket with ***** in 3 trips.

 

[KarlS]

I got near perfect discrimination method. I detect with SPP and stick X Terra to my teenager son. When I get the signal I call him over to check it. It works well for about an hour. Then it seems that batteries go flat. Not on the detector, on my kid. Then he buggers off to do his own thing and my discrimination feature disappear.
Karl

 

[old hand]

The dics on any of the ML detectors from the 2200 to the 5000 is very limited ,it does work but its just a disc and that's it regards john

 

[GypsyGoldAu]

Im finding since using a gpx im digging loads of junk at extreme depths its becoming off putting spending all the detecting time digging trash. Will give the dd a go in discrim and hope for less junk next time. Have filled up a bucket with ***** in 3 trips.

Hi Picker, i know finding trash is not the end game, but i refer you to post #6 above as to why finding trash is a good thing. You are also doing a good thing removing the cancer from the earth lol.

Gypsy

 

[Picker]

Im finding since using a gpx im digging loads of junk at extreme depths its becoming off putting spending all the detecting time digging trash. Will give the dd a go in discrim and hope for less junk next time. Have filled up a bucket with ***** in 3 trips.

Hi Picker, i know finding trash is not the end game, but i refer you to post #6 above as to why finding trash is a good thing. You are also doing a good thing removing the cancer from the earth lol.

Gypsy

Which detector did that blanking occur on the 7 ozer Gypsy?

 

[GypsyGoldAu]

Which detector did that blanking occur on the 7 ozer Gypsy?

That was some time ago now (7-8 yrs) but if memory serves me correctly it was either a GPX 4000 or 4500 with a 14" Coiltek DD. It was carrying some heavy ironstone as well so not a bright and shiny cleanskin but more gold than ore on the lump.

The owner left it as he dug it as a reminder to himself (and obviously those he showed it to) about the fallibility of using discrimination and relying on it to justify whether to dig or not.

Cheers

 

[SteelPat]

Im finding since using a gpx im digging loads of junk at extreme depths its becoming off putting spending all the detecting time digging trash. Will give the dd a go in discrim and hope for less junk next time. Have filled up a bucket with ***** in 3 trips.

If you think you're digging deep for *****, try running a GPZ.

That being said, I would rather spend all day digging ***** and knowing I didnt miss any gold. If you run any form of discrimination, you will always run the risk of missing gold.

Down where I detect, a lot of the gold is found in ironstone. It's a tricky combination for any machine.

Its nearly impossible to run a VLF machine due to the mineralisation/iron content of the ground. And, just due to the nature of the design, true discrimination is not possible with a PI machine. I could bore you with the technical details of PI electronics but suffice to say, until there is a radical design change ie using 24bit sampling, ultra high speed coils that produce no back EMF etc, I cant see a true discrimination PI machine any time soon.

 

[Picker]

That's nice where I have been looking there wasn't as much ironstone so probably the vlf's have been through and cleaned up leaving the trash behind. A good tip for what to look for/ type of ground.

 

[GypsyGoldAu]

That's nice where I have been looking there wasn't as much ironstone so probably the vlf's have been through and cleaned up leaving the trash behind. A good tip for what to look for/ type of ground.

The thing with the VLF's is they are only a reasonably "shallow" detection field in comparison to the PI's and this appears to be bearing out in your own experience...be advised that you will reap the benefit if the bigger & deeper gold is there that the VLF's missed.

Good Luck..buckle down and keep digging, you will eventually rewarded if you have done your research.

Gypsy

 

[user 5415]

Correct me if I'm wrong, but isn't the double noise you hear on a target with a mono the front and back of the coil giving you the double signa as you sweep over the target?
I've had the dig me sound, a light and a sharp signal only to dig down and get the double single as I got closer.

I've only heard this on junk but have always assumed it would be the same on gold as lead is so close to gold?

 

[GypsyGoldAu]

Filthy...with a mono you "normally" get two distinct sounds of the ONE response. It will be either UP then DOWN or the reverse of that (wee-ooo or wooo-ee). When folks say they get a double target response is when they swing the coil over a long & narrow target like a nail or bit of wire ( as if the coil is detecting both ends of the target), which when swung at 90* it will give a single and short response.

See my post above about the near 1/4 Oz gold piece (someone PM me so i can send the pic to be put up please...this is SOoo frustrating) and you will see why ya should just dig ALL targets and you will then KNOW in your own mind you have adequately covered the ground, and left less gold behind.

Hope That helps..

Gypsy

 

[GypsyGoldAu]

That being said, I would rather spend all day digging ***** and knowing I didnt miss any gold. If you run any form of discrimination, you will always run the risk of missing gold.

+1 on this comment ^^^^^

Down where I detect, a lot of the gold is found in ironstone. It's a tricky combination for any machine.

Its nearly impossible to run a VLF machine due to the mineralisation/iron content of the ground. And, just due to the nature of the design, true discrimination is not possible with a PI machine.

This comment reminds me of an outing i had about 5 years ago on Father's Day (RIP dad) in the North West of the Whipstick around a renowned ironstone belt. Very shallow ground after the old leases of the 30's & 40's and again in the 80's. Lots of schist's and folded belts of sandstones interspersed with ironstone reefs.

I was returning to the vehicles (4x of us there) for an arranged "cuppa break". The other guys were already there with cups in hand and recounting their morning and disappointments. Forty feet from the group swinging my coil and desperate for a cuppa myself, i get a wooeee response, short & faint. Taking to the ground with the pick i begin almost immediately to hit ironstone banding under the over burden, you couldn't see the ironstone on the surface. Another swing finds i still have a response, yet now it is warbled and wider.

I almost walked away thinking ahhhh it's only hot rocks and actually took two steps towards the cars. However, something about the "undertone" of that response kept nagging at me that it was too positive a response not to investigate further...the guys at the vehicles were watching and laughing at the sound of the speaker response on the target yelling out...It's trash bloke, leave it alone and come and get ya cuppa"..

Well, long story short & needless to say...6" down and 25 minutes later after cracking at the ironstone...out popped a 5.3 grammer from "under" a leg of the ironstone banding..., walked back to the vehicles and declared..."Damn i'm getting sick of digging trash like this ALL day...whilst slapping the nugget down on my mates tailgate from a closed palm....'ol mate looks down and the look on his face as his eyes bugged made me laugh so hard i nearly wet myself.....never a better tasting cuppa in the bush have i ever had to this day.

Didn't even mind i blunted the pick end up that day and it was only a few months old as well. Declared it the Dad Nugget (sadly among the stolen cache) and went home that day happy as Larry.

Anyway, thanks for reviving that memory for me SteelPat.

Gypsy

 

[Golddiga]

I use DD coils on my sd2200d and I use the discriminator on screamers- It is very accurate and I use it for this purpose only (big close targets)
Twapster, you will find that unless you're super lucky most gold targets will be faint and alot of the time small pieces of steel will also sound quite similar- the discriminator can't get enough info from these small trash targets and you will have to dig them.
After a while you will know by the sound your machine makes what shoe tacks, 22 shells, small wire, lead shot and if you're lucky nuggets all sound like.

Later model PI machines (like your 4500) are much more stable and rely less on the use of DD coils. GPX series were designed from the (mono) coil up and as such mono's run as smooth as DD's but have a more sensitive response to targets.

As for knowing what sounds like what...i refute that with my own experience.

eg1; It is stated when you hear a double response over a single swing that it will be a nail or long piece of wire. I hit such a signal one day and dug it anyway (using a mono coil) and lo and behold a 4.5cm long 7.4gm (1/4 of an Oz nearly) chunk of gold. (have a pic but can't seem to get them up on here so if ya wanna see it, PM me your email and i'll show the pic).

eg2; I thought i had "sounds" down to a T with my GPX 4K & 11" mono. Swung over what sounded to my "trained" ear as a piece of junk, dug down 7" and picked out a 2.1gm nugget. I now carry this with me to remind me of just how much i "don't know" and to dig everything.

Now ordinarily, based on my "educated" ear, i would normally have walked past these target responses, but due to being in the habit of dig everything, i ended up being pleasantly surprised.

No matter the operator, or how long they have been in the game, i defy anyones claim of "knowing" what gold sounds like & being correct 100% of the time. I have seen a 7 Oz nugget blanking (overloading)on a discriminater set up detector and since that day (early in my beginnings) i have only used mono coils....and dig everything. You won't know what the target is until you dig it, and gold can be found under the junk.

Do i dig i LOT of junk?.... Hell yeah, but i reckon i leave behind a lot less gold in my journey than others who believe they know what GOLD sounds like. I also tend NOT to walk over Gold to get to Gold, as the saying goes.

Perhaps the targets above are exactly examples of this and i found the gold others left behind in the belief it was "junk"?

Just treat each outing as a treasure hunt and be pleasantly surpised by what you are lucky enough to find imo. Gold becomes a bonus, enjoy being out in nature and part of something more grand than you or I.

Cheers

Thanks for sharing your experience, for newbees like myself these sort of threads are invaluable.

 

[GypsyGoldAu]

Thanks for sharing your experience, for newbees like myself these sort of threads are invaluable.

Glad you got something out of it... I don't know it "all" by any means, but hope that some insight can be gleaned from my posts..hope ya have success in the hobby.

Gypsy