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AQ Impulse, Depth Testing, Emi Rejection Issue


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2 hours ago, ALEXANDRE TARTAR said:

I found this video on YouTube

First "error", you sweep the target below the searchcoil without ever leaving it, the ATS therefore takes over and the detector ends up absorbing the small variations in the target. (recalibrating)

Second "error", we don't ear the audio threshold so we can not ear the small target variations.

The audio threshold must adapt to the listener, here it is the camera, we must hear the audio threshold through the video recording. Of course if you put it on your ears it will be too strong it will have to be reduced for adapt to the ears.
Always a faint hum.

Third "error" it is necessary to adapt to the standard sweeping speed of approximately one meter per second.
So you have to go back and forth below the searchcoil (while leaving the detection zone of 1 meter per second).

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BK...I should be able to reproduce the same results as the video, using the short motion / swing, than I'll show how coil control, a full swing and using the threshold can change the results. Temps look good here thursday, maybe I can do a video than. 

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I’m all for it!  I hope we pin this down and I really don’t have an issue. I spoke with the tech that tested mine at Fisher today and will copy him with an updated video. As soon as the weather clears up I’ll give this another shot. I have a Bluetooth lapel mic that connects to my phone - I can stick this in an ear cup so the audio and threshold are better heard.  Regardless of the outcome I hope to be using it this weekend as there is supposed to be some good erosion at my beaches. And I finally got a negative Covid test after 3 weeks…

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Got a short quick video today, more Friday, took me awhile to get all setup and air traffic was bad, to noisy to hear faints. Have to go get the gold ring also, thought I had it here but must be at the deposit box. As you can see mine only gets 12 using the (same) way you tested...... but a few changes it goes to 15/ faint 16, and I figure I can squeeze more by using my head phones, not stockers either

Listen to what Mike says... if you don't do a full swing the target disappears, coil control is a necessary to get the most out of the AQ..

 

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I retried my test at the park during lunch today but technology failed me.  I was using a bluetooth attached lapel mic inside my ear cup.  It seems to have some kind of noise reduction going on that fails to register the constant threshold I can definitely hear.  (plus my talking is too muffled to understand) So you can hear when the signal exceeds the threshold level so it proves yes, my detector "sees" the targets at 16" but the recording doesn't give a correct representation of the audio so I'll have to record the audio another way. Although, yes I hear the nickel at 15" this way, I feel most tests I've seen others do showed a much stronger signature of the nickel at 16".  OBN your video does represent things much like I experienced and showed I definitely moved the target too fast and rarely outside of the coil diameter - a bad habit after doing this too long with impatience...  my bad.  

I want to get this audio recording figured out, because I often record short things I ask about in forums and the audio is just always poor.  Sometimes I use my iphone, sometimes an old gopro.

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23 minutes ago, bklein said:

I retried my test at the park during lunch today but technology failed me.  I was using a bluetooth attached lapel mic inside my ear cup.  It seems to have some kind of noise reduction going on that fails to register the constant threshold I can definitely hear.  (plus my talking is too muffled to understand) So you can hear when the signal exceeds the threshold level so it proves yes, my detector "sees" the targets at 16" but the recording doesn't give a correct representation of the audio so I'll have to record the audio another way. Although, yes I hear the nickel at 15" this way, I feel most tests I've seen others do showed a much stronger signature of the nickel at 16".  OBN your video does represent things much like I experienced and showed I definitely moved the target too fast and rarely outside of the coil diameter - a bad habit after doing this too long with impatience...  my bad.  

I want to get this audio recording figured out, because I often record short things I ask about in forums and the audio is just always poor.  Sometimes I use my iphone, sometimes an old gopro.

I did more vid today but won't have it up till later Sunday. I did notice this, the higher the Delay on 18k, think I went to 11, the stronger the signal on the gold. Nickel still poor at just 16..and this is todays testing. Like Carolina said, get out there and play with the delays, and other settings..than using the coil with different sweep speeds and different swing styles. Even learn how to pinpoint with it, I found by using the edge of the coil or even pumping it up and down as I slowly move the coil over the faint target ...it will pull up weak signals..... settings today were full volume, sensitivity 8, threshold 4 plus, and it climbs as it gets warmed up.. 

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Joe…..I’ve been saying it for years that higher karat gold doesn’t demand a lower delay. That’s why I’ve never been enthusiastic with US Nickel tests when testing a detector for “gold performance”. Lower delays will definitely hit Nickels deeper but that means nothing to me in my quest for higher purity gold. Now when you combine a moderate pulse delay with a longer pulse width then those bigger high gold content rings can start to show themselves from the depths. Less can often be more.

Additionally, delays of around 20uS make for relaxed hunting…..noise from fast salt and churning black sand and signals from decomposing iron are a thing of the past.

Just for reference, my modified Garrett Sea Hunter XL500 pulse gets these results operating at 20uS delay and with a 350uS pulse width (10” coil)

US Nickel: 11”-12”

18K gold smallish wedding band (see pic): 15”

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In my opinion, the delay range of the AQ is way too narrow (assuming it is even performing to spec).  Eric (RIP) personally told me that the AQ defaulted to minimum delay when the detector was turned on and off, regardless of what the control said.

I cannot fathom how the delay setting cannot modify the AQ’s performance unless there are issues at play. The pulse delay on every PI detector that I have ever used was always the single most “obvious” controllable function available.

What did the max pulse delay finally end up being. I know the dial says 11.5 but did Fisher extend this 15uS ?

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My first video of this thread shows that it seems to lose the EMI setting moving from All Metal to Tone mode. Maybe it loses Delay setting too? I don’t see a way to test Delay without opening it up and I’m not going to do that…  I’ll see how it does tomorrow at the beach but guys aren’t finding much, surprisingly. 

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