Jump to content

Recommended Posts

In a mixed mode do you lose the slight edge in depth that you normally get in AM mode or does it depend on the detector?

On my Tejon even though it is analog, if I set disc 1 to AM and disc 2 for disc mode (clicked out of AM mode) I can hear a faint target but if i toggle to disc2 that sound will be trimmed out even if it is in the metal response range but happens to be on the fringe.

Lastly how accurate would that VID be if in AM mode? I am assuming there would be some sort of filtering for the digital signal processor to be able to display the correct vid based on target response?

Share this post


Link to post
Share on other sites

13 hours ago, kac said:

In a mixed mode do you lose the slight edge in depth that you normally get in AM mode or does it depend on the detector?

I think it does depend on the detector.  I think in the pure audio mixed mode implementations that Mike was referring to as the more traditional mixed mode implementation, you do no lose anything.  AM on the F75 is AM and the AM audio is unaffected even though you do get a visual target ID.   The issue arises regarding whether the detector in "All Metal" is truly giving a raw, unfiltered all metal audio signal or simply processed audio but devoid of any "discrimination" filtering.  In other words, no discrimination "pseudo All Metal" does not necessarily equate to "true All Metal" where no signal processing/filtering is occurring.  In the former, even though there is no discrimination filtering occurring, there may be other signal processing/filtering going on.  I think the Equinox is a good example of this as well as the Deus, where a true all metal audio output is more a voltage controlled oscillator (VCO) audio that is proportional to signal strength (volume) and phase shift (pitch) of the target signal.  The Equinox does not do this when all discrimination is removed (even in the pseudo VCO audio of gold mode) and with the Deus, even though a VCO output is provided in Gold Field mode (perhaps the closest thing on the Deus to true all metal) the signal is still processed through various signal processing filters.

  • Like 2

Share this post


Link to post
Share on other sites
1 hour ago, Chase Goldman said:

In other words, no discrimination "pseudo All Metal" does not necessarily equate to "true All Metal" where no signal processing/filtering is occurring.  In the former, even though there is no discrimination filtering occurring, there may be other signal processing/filtering going on.

Filtering is something I, for one, am confused about.  Take the Fisher F75.  There are two "all metal" modes:  motion and non-motion.  From my understanding, non-motion mode is used by many detectors when they are put in pinpoint mode.  On the F75, the detector's sensitivity (and I prefer to use this term as a result or consequence as opposed to a control, i.e. 'gain') is stronger when in non-motion.  Does this mean that motion all metal mode is actually resulting from some filtering?

Share this post


Link to post
Share on other sites
24 minutes ago, GB_Amateur said:

Filtering is something I, for one, am confused about.  Take the Fisher F75.  There are two "all metal" modes:  motion and non-motion.  From my understanding, non-motion mode is used by many detectors when they are put in pinpoint mode.  On the F75, the detector's sensitivity (and I prefer to use this term as a result or consequence as opposed to a control, i.e. 'gain') is stronger when in non-motion.  Does this mean that motion all metal mode is actually resulting from some filtering?

That is a good question.  The "auto-tune" feature that enables a detector to not have to be constantly retuned is a convenience feature that resulted in the boon of motion based induction balance detectors in the 80's.  Detectorists were enamored with not having to futz with re-tuning their detectors to provide the ideal threshold level which was easily thrown off by various things including drift in the detector circuitry to changing the height of the coil above the ground or changes in ground characteristics.  This ultimately resulted in silent sweep detectors where the threshold was eliminated completely.  The problem with auto tune was that the coil DID have to remain in continuous motion in order to hear the target otherwise the auto tune circuit would cancel out the target signal.  Having a true threashold and non-motion detection without the benefit of autotuning results in the most sensitive detector overall.  So the autotune circuit does tend to reduce sensitivity because it manipulates the output requiring swing motion vs. a true all metal, non-motion mode, but not because signal processing filtering is going on, in the strictest sense of what "filtering" means.

Steve's article on Threshold Autotune, Sat, and V/Sat explains the background on how induction balance detectors evolved from primarily non-motion mode to motion mode, a lot better than I did here.

  • Like 2

Share this post


Link to post
Share on other sites

Thanks for that explanation and double thanks for linking to Steve's excellent article (original from 2010?).  Even though I had read it before I had forgotten about it AND it hadn't really sunk in.  Both are common for me these days.  🙄

 

  • Like 1

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

  • Similar Content

    • By ☠ Cipher
      I would like to see what any of you have created as far as displaying your metal detectors at home. I'm looking for creative ideas to make a home display myself. I'm entertaining many ideas from open to closed displays, even using Curio cabinets. To be clear, I'm looking for ways to display machines primarily, which could be mixed with finds as well. 
    • By principedeleon
      Hello everyone ..
      I wonder if there anyone who uses a 3D metal detector to locate gold deposits @ around 15 to 20 feet deep... 
      I have heard of larger nuggets of 1 and 2 pounds in size and gold deposits with 300 grams in a bucket of dirt being found in the river banks. 
      Could a GPX with the New 30" coil   could reach a 1 or. 2 pound nugget  @ 4 feet deep... 
      Im not interested in the finer gold just the bigger nuggets or a large concentrate of gold ..
       
    • By rled2005
      This is a nice concept. If works I can see a lot of interest.
       
       
    • By Steve Herschbach
      The cell phone is now a common day device owned by most people. It was inevitable that a metal detector designer would mimic the look and feel of a cell phone in an attempt to modernize how metal detectors are perceived. As far as I know it was Quest (back when they were named Deteknix) that first came up with this design. Or at lest they were the first to really market something like this in 2015. Then we next got the Minelab Equinox in 2018. And now the Nokta/Makro Simplex+ in 2019.
      Some might call this copycat designing but form follows function to a certain degree and all items copy others in some ways. All T-shirts have a head hole and two arm holes. Still, I think Deteknix/Quest gets the credit here for first popularizing this design. I'll be surprised if more are not to follow.

      Quest metal detector

      Minelab Equinox metal detector

      Nokta/Makro Simplex+ metal detector

      Quest metal detector controls & display

      Minelab Equinox metal detector controls & display

      Nokta/Makro Simplex+ metal detector controls & display
    • By DSMITH
      Can someone explain to me what makes this new Anfibio different from a X TERRA 705 the 705 can run three different frequencies all be it you have to change coils to be able to run any of the three different frequencies it can run the Anfibio you push a button to change frequencies but with that being said I also know I can purchase a coil from a manufacturer that pretty much allows me to run one coil on the 705 and just by turning the 705 off and back on in a short time period it changes to one of the different frequencies that the 705 can run in in other words one single coil will run 3 KHz,7.5 KHz,and 18.75 KHz all done with just one coil so can someone please explain how the Anfibio is any different from the X TERRA 705 and not trying to start a bashing war here just trying to understand how the Anfibio is much different from the 705.

    • By Steve Herschbach
      High Frequency Gold Nugget Detector Roundup
      Our cup runneth over!
      Just a few years ago the market for "over 30 kHz nugget detectors" was quite limited. For a long time there were only a few options:
      Fisher Gold Bug 2 (71 kHz) $764 with one coil
      Minelab Eureka Gold (6.4, 20, & 60 kHz) Discontinued $1049 when new with one coil
      White's GMZ (50 kHz) Discontinued $499 when new with one coil
      White's GMT (48 khz) $729 with one coil
      Things were that way for over a decade. Then in 2015 Makro introduced the Gold Racer (56 kHz) $599 with one coil. Sister company Nokta released the AU Gold Finder (56 kHz) $799 with two coils
      Then in 2017 we see the Minelab Gold Monster 1000 (45 khz) at $799 with two coils. And although not a dedicated nugget detector, the Deus high frequency coil options (up to 80 kHz) were also released, $1520 for complete detector with one HF coil.
      Now in 2018 we get another general purpose machine, the Equinox 800, that can hit 40 khz, $899 with one coil. And just announced...
      the Makro Gold Kruzer (61 kHz) $749 with two coils and
      the White's Goldmaster 24K (48 khz) $729 with one coil
      These last two announcements have made barely a ripple in the prospecting world, or at least going by other forums that seems to be the case. There are various reason for that (forums not being prospecting oriented or being Minelab centric) but still the lack of buzz is interesting. I do believe people are both burned out by all the new introductions and that the market is saturated with high frequency models. Leaving out the general purpose machines to sum up the current options it looks like the current "sweet spot" for pricing is a high frequency model at $749 with two coils. The Gold Bug 2 saw a price reduction to $699.
      Makro Gold Racer 56 kHz - $599 one coil
      Fisher Gold Bug 2 71 kHz - $699 one coil
      White's Goldmaster 24K 48 kHz - $729 one coil
      White's GMT 48 khz - $729 one coil
      Makro Gold Kruzer 61 kHz - $749 two coils
      Minelab Gold Monster 1000 45 kHz - $799 two coils
      Nokta AU Gold Finder 56 kHz - $799 two coils
      Added 1/2019 XP ORX up to 81 kHz - $899 one coil

      High frequency nugget detectors compared

      White's Goldmaster 24K, Minelab Equinox 800, Gold Monster 1000, Makro Gold Kruzer

      Minelab Gold Monster, Fisher Gold Bug 2, Makro Gold Racer, Nokta Impact
×
×
  • Create New...