GP Extreme coil questions

[Daniel Tn]

Is there any differences between the standard GP Extreme coil and the new Commander coils by Minelab? I was wondering if they were basically the same thing, or if it would benefit me to get one of the newer coils. I have ran a GPX 4500 and 5000 in the past...but just recently got my hands on an older GP Extreme. I noticed that for whatever reason, the iron discrimination isn't as good on the GP Extreme as it was on the GPX 4500 & 5000. It works...but only at a much shallower depth or so it seems. I didn't know if they had really advanced that area between the time gap of the GP Extreme and 4500 or if maybe it was the coils that help a little bit. Thought I would ask.

 

[steve herschbach]

Hey Daniel,

The Iron Disc was a bit weird with the extreme. Have you fiddled with the Level Adjust? Excerpt from manual below. On the GPX the Disc gets its own expanded control and everyone I know thinks the GPX disc can actually be made to work halfway well. Never use it myself.

The Commander coils are heavy but the best you can get as far as how they work, in my opinion. Have to say I am doubtful this will solve your issue as the GP coil is basically a Commander coil also. Hate to tell you the GP Extreme was kind of like Fishers these days o there were hot one and cold ones. The GPX series seems very, very consistent by comparison.

"Level Adjust Control
Level Adjust gives the user the ability to select the sensitivity and
likelihood of a target being discriminated as ferrous when used in
the Disc mode.
This may also affect how the detector responds to ground
mineralisation compared to metal targets when used in Disc. Mode.
There is usually some overlap between signals from useful targets
and some types of iron rubbish. The user may set Level Adjust to
select the amount of discrimination between two extremes: • (Fully anti-clockwise). All targets detected, but some iron will
give a normal signal (as per Figure 5.4).
• (Fully clockwise) Little iron detected, but some small nonferrous
targets potentially mistaken as ferrous.
Turning the control anti-clockwise increases the strength of a signal
required for iron discrimination to be activated.
The Level Adjust also affects the Tracking mode.
When set fully clockwise, it is unlikely the detector will 'balance out'
genuine targets, but some ground noise may still give false signals.
When set fully anti-clockwise, the detector will 'balance out' ground
noise effectively, but some faint, weak target signals may be missed
after repeated sweeps of the coil.
HINT It is usually best to dig out all targets and only use the
discrimination function in areas where a large amount of rubbish
makes the digging of everything impractical.
NOTE Discrimination functions will only work with strong,
positive target responses. Weak responses will give normal 'all metal' type signals.

 

[Daniel Tn]

From what I have tested, the GP Extreme I have is going to be OK for what my intended purpose is. I can see where they have upgraded in steps along the way. With me having gone from a GPX backwards....well in some ways I wish I could have found a good used GPX for a good price. But considering this wont be a primary machine for me, I think it will do. I believe it's above where the Whites TDI is in depth...but I don't think I'm going to be pulling any 18-20 inch bullets with this one.

The iron disc seems to work pretty good down to a certain depth. It just seems like I recall the GPX machines being able to break up the signal on iron a little more pronounced and deeper than what this one is doing. I've not maxxed out the adjustment knob as of yet...I'm afraid by doing so it will break up deeper non ferrous targets. Today would have been the first real day of actually getting to hunt with it...except the rain had other plans.