GMP 9" coil v 11" air test

Only for the discussion of the XP Gold MAXX Power Metal Detector.
Post Reply
Bazza
Posts: 167
Joined: Tue Mar 26, 2013 6:56 pm
Location: Portsmouth

GMP 9" coil v 11" air test

Post by Bazza » Tue Jan 27, 2015 9:26 pm

Hello everyone

I know air tests don't bear any relation to what happens in the field , but I thought I would share just to show the comparison between the two.

Both tested with the same setup.
Silencer at 2 , sens at 1 o clock, iron volume 10 o clock , iron threshold at 10 o clock.

9" inch standard coil 11" coil

45mm bronze medal. 10". 12"
50mm medieval dogs head spout. 10.5. 12"
1920 florin. 10". 13"
20mm lead seal. 8.5". 11"
1936 sixpence. 8". 11"
Ship halfpenny. 10.5". 12.5"
Victorian penny. 11". 14.5"
Lizzy 1st penny 7". 9.5"
Edward 11 penny. 9". 10.5"
Charles 1st rose farthing. 6.5". 8"
28mm brass fob seal. 10.5". 13"

It looks like there is about 2" to 3" increase over stock coil. Need to try it out this weekend to see if any real difference . The 11" does seem not too far behind the SEF 12x15 detech coil which I also have , but do find that a bit too big to wield all day.

Thanks for looking. Good hunting.

Bazza


Garrett AT Pro / Goldmaxx Power
Garrett Euroace
Garrett pro pointer

Koala
Posts: 4758
Joined: Thu Sep 12, 2013 2:47 pm
Location: Cheshire
Has thanked: 390 times
Been thanked: 1389 times

Re: GMP 9" coil v 11" air test

Post by Koala » Wed Jan 28, 2015 12:16 pm

The increase sounds about right. You normally get around the same depth in soil as the coil diameter on a 2p size object.

Never tested a GMP. Sounds a little low in air. My detector is 15" on both a copper 2p and a iron clad one with a 10" coil


Tested a Golden Mask recently with a 7" coil. Only tested with a Henry V cut half and that was 7". I was very impressed


I know that old Tesoro detectors are reputed to test low in the air but don't loose as much in the ground but never heard the same for the GMP maybe a tweak of the ground or threshold controls.

Bazza
Posts: 167
Joined: Tue Mar 26, 2013 6:56 pm
Location: Portsmouth

Re: GMP 9" coil v 11" air test

Post by Bazza » Wed Jan 28, 2015 10:21 pm

Hi Koala

Yes your right the air tests are a bit short on expected distance , but the reason I got the 11" was in answer to an earlier post about the minimal depth on the Gmp. Tomo did some tests with it on a buried coin and some tweaks on settings and improved the depth. Generally the feeling is at the frequency it runs at depth will be an issue. Quite happy with the apparent improvement . On the land I detect that 2 or 3" could make all the difference. I have the Garret AT pro which does punch deep but it is heavier and the headphones connected are a pain some times. I like the wireless phones with the XP.

Time will tell if there is a difference.sometimes just having faith in your machine seems to improve your finds.

Bazza
Garrett AT Pro / Goldmaxx Power
Garrett Euroace
Garrett pro pointer

bob the diggerer
Posts: 70
Joined: Mon Feb 16, 2015 4:08 pm
Been thanked: 8 times

Re: GMP 9" coil v 11" air test

Post by bob the diggerer » Mon Feb 16, 2015 7:33 pm

I have the 9" and the 11" inch coils, and do have a similar gain of up to 2" in air, out in the field its hard to notice as that amount of depth is difficult to judge, I use two tone on both, but I think it mirrors the air tests for depth, what I have noticed using the 11" is a considerable increase in the more smaller good signal items. I use the 11" with ground balance slightly less, at 12,oclock position, rather than 11,oclock for the 9" I now prefer the larger coil, which I find balances better on a straight shaft, for most clear ground.

Koala
Posts: 4758
Joined: Thu Sep 12, 2013 2:47 pm
Location: Cheshire
Has thanked: 390 times
Been thanked: 1389 times

Re: GMP 9" coil v 11" air test

Post by Koala » Mon Feb 16, 2015 9:27 pm

bob the diggerer wrote:I have the 9" and the 11" inch coils, and do have a similar gain of up to 2" in air, out in the field its hard to notice as that amount of depth is difficult to judge, I use two tone on both, but I think it mirrors the air tests for depth, what I have noticed using the 11" is a considerable increase in the more smaller good signal items. I use the 11" with ground balance slightly less, at 12,oclock position, rather than 11,oclock for the 9" I now prefer the larger coil, which I find balances better on a straight shaft, for most clear ground.
interesting your small finds went up.

if an item is near the maximum depth of detection you will give an iffy signal. If you now add an extra 2" of depth the item is easily detected by your machine. Guess a lot of little items you were walking past you are now digging

Bazza
Posts: 167
Joined: Tue Mar 26, 2013 6:56 pm
Location: Portsmouth

Re: GMP 9" coil v 11" air test

Post by Bazza » Mon Feb 16, 2015 10:37 pm

Hi all

In answer to Koala , I think your right the extra 2" to 3" inches will turn those real iffy signals on the 9" into quite good on the 11" . Have used the 11" now for a couple of Sunday.s .

It is defiantly going deeper ,but the downside is it is a bit sparky on the normal settings I use. I have had to drop sensitivity down a bit . Does not seem to affect the depth to much doing this.

The first week with the 11" resulted in my first saxon coin. Very small 10mm at depth.( see my post from last week )
Would I have got it with the 9" ? , not sure.
Just to say that at the moment I am quite happy with the 11".

Bazza
Garrett AT Pro / Goldmaxx Power
Garrett Euroace
Garrett pro pointer

Koala
Posts: 4758
Joined: Thu Sep 12, 2013 2:47 pm
Location: Cheshire
Has thanked: 390 times
Been thanked: 1389 times

Re: GMP 9" coil v 11" air test

Post by Koala » Tue Feb 17, 2015 7:15 pm

Congratulations on your first Saxon. Success always gives you confidence in your machine.

::g ::g ::g ::g ::g ::g ::g ::g

Post Reply

Return to “XP Gold MAXX Power Forum”