Comparing the GPX 4500

I went out the other day with my mate to check my new GPX4500 my mate has a 3000 we dug a hole about 4" put a .4 gram of gold yep we could hear that went down another 2" no signal with mine and a signal with his 3000 l had 11" mono he had 14" dd elite on so l put my elite coil on still nothing tried different settings on the 4500 went back to the 11" mono coil tried different settings with that and still no signal at 6" my mate was very pleased with his 3000 he dug out another inch and could still hear it so much for the 4500????????????????
Not a happy chappy l can tell you but what is $5700 spent on a detector when a 3000 can do better. So what is that normal for air tests or should l not take to much into that sort of test. We spent 2 hours reading notes changing coils etc
but no signal at 6" dam dam dam

Wow thats got to suck must be a reason for that in the tuning I hope

Neale from Monto Queensland

New
Not sure about air tests as in doing the test there is no mineralised dirt between the nugget and the coil.Gold can be masked by mineralisation.As the 4500 has a quiter threshold than the 3000,in a real situation would the 3000 have recognised the target in the first place.Or would the 4500 have picked it up because of its quiter threshold.The 4000 and 4500 have a history of finding smaller gold deeper.To be sure of your machine the best way is for you and your mate to radio up and call each other to test on un dug nuggets.I can appreciate your concern,I wasted a whole season running a 4000 with a large mono on sensitive smooth timings chasing deep gold .If your machine cant at least match the 3000 on un dug targets I for one would be sending it back
Cheers Dig

I like air testing but only when comparing coil strengths. Air testing should probably only be used to test the strength of one coil compared to another. Not for legitimate targets if you want to test performances against nuggets etc. There's too many factors that come into play which might interfere with your experiments.

Earlier this year, I ran a GP 3000 and a GPX 4500 together (one at a time) and tested them together with the default GP search coils in Default mode/settings. With larger nuggets at various depths, they preformed much the same... with little or no noticeable difference where we were testing them.

But when it got down to a .25 gram 'nugget' with a flat/large surface area, the GP 3000 could NOT respond to it, even when the nugget was placed on the surface. The GPX 4500 was able to sense the nugget but the signal was only very faint. I doubt that it would have found the same bit of gold at ANY depth. Now this was done without using the special settings on the GPX.

6 inches of depth on a sub-half-gram bit of gold might be pushing your luck without the use of a more sensitive coil. Obviously small and medium size Monoloops would be ideal. But without knowing what settings you might have overlooked on your GPX means we may never know the answer. In theory, your GPX should have the upper hand on small gold compared to the GP. But a single switch setting or tuning error would dumb your detector down in an instant.

Note also that you might have had more metal on your body at the time you conducted the tests. The electromagnetic filed coming from your detector coil will interract with all metals near the coil. If you had more metal or a larger belt buckle or even a number of coins in your pocket with a large surface area, these things will hamper the strength of your coil with smaller items. I would certainly consider a .40 gram bit of gold to be a small item. Most people hunting these sized nuggets on a regular basis tend to use mini-coils or "sniper coils'. Six inches is getting fairly deep for a detector to sense mini-gold in mineralized ground. My guess is that you had a single setting that was off... or you were carrying more metal.

I would have backed your 11 inch monoloop over the larger Double-D coil. Bit of a mystery. Were both machines running at the same time? How old are both of the coils. Most coils break down over time. I believe some brands break down faster than others. Some of the reasons include UV light, moisture-bleaching and exposure. Even approaching the nugget from opposite directions with your coils will give different results.

Cheers,

Marco

Newhunter wrote:l had 11" mono he had 14" dd elite on so l put my elite coil on still nothing

G day Newhunter
I'm sure some of the 4500 experts will set you on the right path with settings etc but just so you know the 14" DD pro elite ( the tan one ) was designed for the SD GP series and won't give any advantage on a 4500 over the old orange 14" DD pro coil.
The elite coil is a very sensitive coil on my machine, 2200v2

Brett

Fisherman wrote:...the 14" DD pro elite ( the tan one ) was designed for the SD GP series and won't give any advantage on a 4500 over the old orange 14" DD pro coil.

That there is probably the answer!

And (just to even things out) Coiltek Goldstalkers have the reverse effect by being more sensitive on the GPX than on the SD/GPs.
That's almost certainly the answer... especially since we're dealing with gold under a half-gram.

Well my mate tried my detector as well so the metal thing should not have been a problem the 11" Commander mono is new as l said we tried a lot of different settings most of which l got from this forum and JP's the seta project but it would not pick up signal at 6" so you tell me a 11' mono on the 4500 and a 14" dd elite on the 3000 and it picked up a signal and mine did not. I wont give up but l dont know what other settings to try will just have to work it out. But thats life some good some not so good

Congrats AA
Cheers Dig

New Hunter,
You wrote; "we tried a lot of different settings most of which l got from this forum " These settings are only a starting point, there are so many ground differences, EMI interferences, your machine must be set to the this variance on the day.
I don't see any mention of "Gain"?
Did you experiment with the gain and stabilizer settings?
While I am swinging my view screen is always on Gain, if I am running my GPX-4500 on a mid range setting and get a very mellow signal my first response is to bump up the gain. Usually, but not always if the signal jumps up it is a metal target.

Don't lose hope, keep experimenting and feel sure you will wipe the smile of your mates dial.

Peter

l hope so like l said l tried high gain low gain stabiliser up and down ran in mono and dd normal enhanced special fixed tracking slow very slow medium fast volume up threshold up and silent deep extra different sweep speeds and a lot more that l cant remember we tried for 2 hours to get a signal out of the dam thing. But like you say dont give up just keep at it. There must be something l am missing so l will keep at it.

Theres a test rig near Maryborough Vic that Coiltek can direct anyone to.Prices rd.Its a good place to test machines
Cheers Dig

Hi all we went out again today got better results than the other day charged up the battery went to a different spot (500 metres from the other hole we dug) and got better results as good as my mates 3000. l also took out my 3500 as well and all picked up the same piece of gold at 7" today l dont know why the differance to the other day. But l can tell you that when l got home l had 2 cans of bundy & cola. Now let me at them gold fields.
Thanks all Gary