AQ Impulse, Depth Testing, Emi Rejection Issue

[Joe Beechnut OBN]

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..

 

[bklein]

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.

[Joe Beechnut OBN]

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.. 

[Tony]

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”

[bklein]

I’d like to see someone show how the delay setting modifies AQ behavior. I just don’t see it. 

[Tony]

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 ?

[bklein]

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. 

[bklein]

Found two rings and about a dollar in change. I found so many tent stakes that I went to tone mode. Right away I hit a goldish ring. No marks, not likely gold. As I was leaving the wedge area I tried the volleyball court and found the probably stainless ring. AQ worked great.

[Carolina]

Thank goodness you finally got out with the AQ. Tone mode is 98 percent of my usage. Those 18k pigs will give a iron grunt, but the majority of them are deep in the wash on the rim so there I always dig the grunt. 75 percent of my rings come from lower to mid beach. I skip all the iron grunts there as it is mostly clad and or tent stakes and the likes. Time is of the essence in fresh drop season so I have little time for tent stakes. I pass up all pings off the edges also and pay attention to shape. If upper mid beach and lower gives a solid ping in tone mode, you can almost bet its gold. Good luck everybody!

[Joe Beechnut OBN]

On 1/6/2023 at 11:09 PM, Tony said:

 

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

If this is, I would say it looks good. Rarely do I go lower than 9. something that seems to work both of my AQs. If it is noisy at 10, I'll go up with the delay..calm the machine down. than go back down to 10 which is what I run most of the time. And this takes about 15/20 minutes. (looks like I am using 12 delay, going up to  15/20 than back to 12) .......Also the AQ is a warm up machine, the threshold climbs the first 15+ minutes, after adjusting, (lowering) it steadies.