Axiom Focused Core DD Coils - A Must Read For All New Owners!

[Gerry in Idaho]

8 hours ago, HardPack said:

Let me ask this…

Steve,

Would the 13x11 mono coil work on the ground you were detecting?

Gerry, 

Would the 13x11 DD coil work on the ground you were detecting?

 

Easily with out a doubt. This is a very smooth detector and better than what I was expecting. 

[HardPack]

“This can be confusing at first, but actually gives a trained operator extra information about the size and depth of the target. Small targets will "tone-flip" front to rear, with the classic hi-lo tone in the center. Larger targets at depth will no longer tone flip, but just deliver a stand hi-lo or lo-hi response.”

Small targets will “tone-flip” front to rear… What?

You mean hi-lo at the front edge of the coil then lo-hi at the rear edge of the coil as the DD coil is moved front to back over the small target ???

[Steve Herschbach]

Yes. Look at the diagram I posted earlier in the thread.

[HardPack]

Okay Steve, Let see if I am even close:
The new Garrett Axiom Pulse Induction DD coils transmits from one D coil, pauses then receives with the other D coil. The DD coil(s) crossings are set back from both the forward toe and the rear heel of the coil housing creating a smaller interior mono coil “focused core” centered on the north/south center line of the main coil housing axis. The detection depth of the main PI DD coil will be deeper than the smaller interior mono coil. After detecting a target when sweeping the coil left to right (as in marching) a hi-lo or lo-hi external signal will be received from the command center. At this time flank 90 degrees to the side and sweep coil left to right listening for a repeatable command signal. Now push then pull the coil over the target area. If it is a larger deeper target the signal should remain lo-hi when passing over the forward DD coil crossing & lo-hi without “tone flipping” to hi-lo when passing over the rear DD coil crossing. If it is a shallower smaller target the signal will be hi-lo, hi-lo on the left/right sweep but will “tone flip” when pushing over the rear DD coil/mono coil intersection. At the same time the field operator is to combine all the above with the external incoming proportional audio. All this may vary based on ground conditions, soil type, target size, target conductivity, actual target depth, target tunnel abilities and field operator IQ.  Seems simple enough.
 

Okay Garrett, keeping in mind some of us are more amphibious by nature, this is what we need for gold detecting. A simple waterproof 5x9 mono coil with a sensitive forward located tip so we can replace the water-logged sand impacted White TDI, 5x9 folded mono coil equipped with your brand new Garrett Axiom equipped with a WR-1 quarter inch jack receiver plus your newly developed Garrett Axiom WP 5x9 mono coil specifically designed for left to right sweeping and forward pushing as needed; green in color if possible. Thank you for your engineering and have a Merry Christmas.

 

[Steve Herschbach]

Oh yeah, super simple! Yes you pretty much have it. There certainly is room for a standard DD coil in the mix, that would deliver a more consistent target response on smaller gold. But then you lose that hot spot and the coil is milder overall than the mono, but may work better in hot ground. It's all just little trade offs here and there. Not to worry however. I am all but certain the Axiom will soon have the best coil selection of any detector made since the GPX 5000 came out. I'm pushing for 10x5 mono, 14x9 mono, and some sort of good wading detector, 8" - 11" round. But that is just for starters. An 8" standard DD would be great, etc. I love lots of coils and have been quite frustrated in that regard with some other detectors, so I'm pretty pumped about all this. And soon, not years later. 

The Axiom completely blows the TDI away. The only place I'd not be willing to bet on that is on a beach using the 16V TDI models and with the ground balance turned off. The TDI set up like that is a killer beach machine for moderately mineralized beaches.

[phrunt]

Second that, the Axiom is set to be like the legacy GPX with a big range of coils for it.  Garrett absolutely did the right thing by not restricting coils.  I never thought we'd have another NEW competitive PI be released without control over it's coils, and then Garrett comes along and brings the goods with a modern great performing detector with no restrictions on coils at all so now the aftermarket can do what they do best and that's make coils to benefit the detector in many ways different to the OEM coils.    Good times ahead for Axiom owners.

 

[HardPack]

Seems Garrett simply added the push/pull step to the normaI. I see the Axiom hi-lo duel tone and the DD mono/focused core tone flip as a plus. The 11x7 mono may work for edge detecting cervices for now. Thank for the education Steve.

[Steve Herschbach]

The tone flip does not occur pushing the coil forward and back. It occurs swinging the coil side to side, and the tone depends what part of the coil you are under, front, middle, or rear. You get a signal crossing a winding, so a nugget traveling laterally along the center axis will sound in the middle, but minimal chance of sounding laterally along the nose and rear.

And to repeat though I know you got this, it's only the items close to the coil that exhibit this, typically smaller targets. Targets at depth have a more traditional response.

There is nothing mystical magical going on here. It's just different. Before, we basically had mono and DD. Now there is a third option that acts like both in some ways, kind of a hybrid design. I'm not telling anyone it's better, just different, and people need to know that. Whether they like it or not is another matter entirely. I still generally like a mono, just because I am used to them, and I like the more uniform tone and depth response. But I am having fun with these Focused Core DD just because they are something different, and that's a rare thing in metal detector land. It's knowing and using those differences where I get my edge now and then.

[HardPack]

Okay*. Let me try again.

Traveling north/south down the coil center line, the space between the coil housing toe to the upper coil winding crossing and the space from the coil housing heel traveling up the the coil center line to the bottom coil winding crossing will produce minimal signals on small shallow targets. In general, swinging the coil left to right a small shallow target passing under and laterally (side to side) of the middle mono (focused core) portion should result in a hi-lo tone crossing the first coil winding then “tone flip” to a lo-hi tone as the target crosses under the second winding.

Below the detection depth limit of the middle mono focused core the Axiom PI DD will detect. On large deeper targets at…I’m lost.

Is this correct: The tradition DD the coiling windings cross at the coil housing toe and heel; then run parallel north/south along the full length of N/S center line. The pulse transmits from one D coil, pauses then returns through the second D coil. The narrow space between the parallel center line windings is the primary detection zone for the length of the N/S center line.

At depth does the Garrett Axiom DD produce a lo-hi when the target passes the first winding then a second lo-hi signal as the target passes out of the narrow space under the second winding with no tone flipping? Does this N/S narrow detection zone extent the full N/S length of the coil or just under the middle focused core?

(*you should see me standing in front of one of the new digital beverage dispensers, definitely need to get to town more often.)

[HardPack]

Quote from Steve “Garrett ATX Duel Audio Tones”  including not just duel tones but tone flipping.

“A low/high signal only means "large/strong target" and high/low means "small/weak target". The tones correspond exactly with other dual tone PI detectors like all the Minelabs and the Infinium, as it is a byproduct of the dual channel ground balance system. The flip point between the two signals is determined by the current ground balance settings, but tends to end up somewhere in the region of a zinc penny when in bad ground. Just where depends on the exact ground and ground balance setting. In mild ground it could be far different. I need to experiment more with that, plus determine where the default setting is at.

If you get a target right at the tipping point, you will get a weird "tone flipping" response, that is actually a third tone indication….”