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AQ Impulse, Depth Testing, Emi Rejection Issue

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11 hours ago, stateguy said:

Bklein I suggest you try the test outside with less interference 

exactly. 14.4 V is way to much juice to test indoors.  I even notice EMI in my backyard.


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I’m kinda hoping one of you take the reigns and test in your garage and then the local park to prove your theory.... 🙂  I have an upstairs rear deck that might work. It has metal sheeting and chicken wire embedded in the floor.  The power wiring for our area is underground, under the sidewalk in the front of the house.


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14 hours ago, bklein said:

I have, did that first but video of it was terrible. Results were the same. I’ve seen French videos of guys getting 16” in their work areas…


No need to answer me. EMI is always the quietest 5:00 AM. Now your settings are no where the same as Joe’s at the beach, which you said you watched. Lower your ATS to “0” lower your reject to “0” raise your sensitivity to “10”. Set your delay on “11”. As I have told you many times, the machine defaults to 7 uS every time it is turned on no matter what the dial is set on. I see yours is set for 7 so after you turn it on, rotate to “11”. These are extreme settings and sweep speed is critical but can be achieved as Joe shows.

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There is a buck boost, the power supply is maintained continuously at 15V, if the battery is at 16.8V it lowers to 15V and if the battery is at 12V it increases to 15V. Thus there is no loss of sensitivity over time. You have the same performance until the complete discharge of the battery pack.

The detector is not designed to be used near residences, yes it is an EMI problem and you will not be able to cancel it near residences. Too high sensitivity is the enemy in this case as your target signal will be hidden by EMI

In my laboratory it's different I canceled a very large number of noises generated by household electrical appliances. But I admit that for me it behaves 5 times better than a VLF at the same place.

If you used a VLF under the same conditions at 100% sensitivity it would be even worse I guess.

The offset frequencies cover 50hz and 60hz but there is no miracle  for all sensors around electrical devices. (motor, fridge, freezer, neon tubes, neon lamp, leds, various electric dimmer etc...)

It's a wet sand beach design only.

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Unlike VLF or multifrequency which decides for the user what is good or not and loses a lot of sensitivity.
The analog PI transcribes all electrical variations into an audio signal.

You decide, not the machine !

All of the following conditions will lead to loss of sensitivity if they are not respected:

- Audio Threshold too high: masks the small target variations so deep variations.
- Headphones with low gain on the piezo or speaker: performance may be reduced by 15 cm on the US nickel. The audio gain directly becomes the detector gain.
- Too strong EMI, in general they are linked to human activity, can mask small variations and cause the detector to lose 50% of its sensitivity.
- A sensitivity that is too high depending on the search areas can generate a lot of EMI and you fall back on the case of appearing explained previously.

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I have family in town till next week. Once all has settled down I'll do a few test and see if I can duplicate past test. Can you give me a detail description of your gold ring..K / purity...weight...shape/design so I can use close to the same. Also make yourself a better set of head phones, the AQ stock head phones are good but to squeeze every inch out of it you need better audio. I'll make you a list of what I used for that next week.


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I have a Trifield meter which senses various interferences. I took it around the house and found an area behind my house that has a minimum measurement.  Wasn’t really that bad in the garage though so maybe it’s meaningless (2.1 vs 2.3mg weighted mode, it’s 2.9mg right now at 7:40PST).  If you have read my other thread though you will see my 12.5” coil died on All Metal so I need to fix that tomorrow morning.

I added the video of the 12.5” coil failure behavior to the thread.

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