Jump to content

Speculations on Minelab SDC 2300 and MPF (Multi Period Fast)


Recommended Posts

Minelab does love their acronyms! MPS (Multi Period Sensing), DVT (Dual Voltage Technology), SETA (Smart Electronic Timing Alignment), FBS (Full Band Spectrum) and a host of others. There is a bit of marketing wizardry at work here but the basic fact is this stuff is real and is very often what gives Minelab an edge versus the competition. When Minelab comes up with a new acronym I have found it is worth paying attention to.

The soon to be released Minelab SDC 2300 introduces a new acronym - MPF for Multi Period Fast. This refers to a basic pulse technology limitation - the duration between when the transmit (TX) mode shuts off and the receive (RX) mode kicks in. This "pulse delay" is a brief window measured in microseconds (uS) and it allows time for the electronics to settle before the receive phase. It also governs how small a target a PI detector can detect, as during that brief delay the signal induced in the target decays rapidly. If the target signal decays in a time frame shorter than the pulse delay the target is invisible to the detector. Small targets and poor conductors especially are governed by this limitation.

The plus side is the signal from most ground, hot rocks, and salt water also disappears during the short pulse delay period, which is what makes PI detectors work so well. Due to a desire to limit the signal from salt water plus limitations in mass production of coils the shortest pulse delay commonly seen in consumer detectors is about 10 uS.

Here is what Minelab has to say about MPF:

"MPF Technology - MPF (Multi Period Fast) technology incorporates extremely fast Pulse Induction switching between Transmit (Tx) and Receive (Rx) detector signals. Therefore minimal residual transmit signal is present during the receive cycle, enabling clear sharp detection of very small gold."

post-1-0-53441600-1400537078_thumb.jpg
Multi Period Fast (MPF)

PI detectors can be designed with a shorter pulse delay than 10 uS, but it takes very tight tolerances and especially very well built coils. This normally requires units to be hand built and calibrated, increasing their production costs considerably. Much of this has been discussed on Tom Dankowski's forum in the past regarding beach detectors and the limitations thereof.

This is pure speculation on my part but I do believe the MPF technology aimed at delivering enhanced small gold capability is also partly responsible for the price of the SDC 2300 and the fact the coil is hard wired. Both make absolute sense given what I think I know about building a PI specifically designed to detect small gold.

That ability comes at a price, as the detector may have issues also with hot rocks and salt water, but these can be overcome through ground balancing technology. It is a tough nut to crack and produce at the consumer level, and many people at Tom's forum have been wishing for just this kind of detector. The potential exists not only for gold prospecting but micro-jewelry detecting.

Anyway, time will tell and hopefully answers will be forthcoming soon. I am in line for a SDC as soon as I can get one and it may fill a role I have never focused on with my GPX 5000 - getting the small stuff. I have seen what a GPX with a small coil can do if properly tuned and in expert hands and I am hoping the SDC is set up to be more grab and go for that type of detecting. That way my GPX remains my elephant hunting gun and I will grab the SDC to clean up the crumbs. It may make previously pounded locations "come alive" again in missed gold nuggets.

I have been ignoring the SDC waiting for mid-2014 to get closer and now that it is sneaking up I am doing my usual get excited by new toy thing!

 

More information on the new Minelab SDC 2300 at http://www.detectorprospector.com/gold-prospecting-equipment/minelab-sdc-2300-waterproof-gold-nugget-detector.htm

post-1-0-57023300-1400537088_thumb.jpg

post-1-0-38716400-1400601857_thumb.jpg

Link to post
Share on other sites

The potential exists not only for gold prospecting but micro-jewelry detecting.

 

 

It will be interesting to see if the SDC2300 as a “Pulse Induction” detector will be capable of detecting micro-jewellery as Steve has made mention in the above quote that I have taken from his posting on opening this thread. Pulse Induction does appear to struggle on this type of micro – jewellery.

 

Also I wonder if the SDC using its MPF technology will be capable of detecting thin tube of high grade stainless steel as used for hypodermic needles since Eric Foster said some time ago in a thread on Geotech that his fastest Pulse Induction detector at that time using a 1us delay with a 2.5 inch coil could not detect this type of needle.

Link to post
Share on other sites

Hmmm, with a PI machine you're energizing the coil to create the field.  When you turn power off that electromagnetic field collapses on itself and generates its own electrical signal.  (Faraday's Law)

 

That's why you need the delay, to let that current from the induction-field collapse to be handled (at least, that's my understanding of it.)  It'll be interesting to see if they've found a way to either attenuate that current, or somehow protect against it (which, IMO, would be the more interesting option since that has some really wide ramifications into other fields!)

 

Hope you get one soon and can fill us in!

Link to post
Share on other sites
On 5/19/2014 at 6:03 PM, goldenoldie said:

Also I wonder if the SDC using its MPF technology will be capable of detecting thin tube of high grade stainless steel as used for hypodermic needles since Eric Foster said some time ago in a thread on Geotech that his fastest Pulse Induction detector at that time using a 1us delay with a 2.5 inch coil could not detect this type of needle.

I am sure we will not be seeing a 1 uS delay; something around 5 uS to 8 uS would be more feasible.

From Link deleted since Findmall update broke all old links

"High sensitivity industrial PIs which can detect fine gold chain would have a pulse delay of 5uS or less, a much faster pulse rate, a short transmitter pulse and a lower inductance coil, maybe 50uH."

See also Link deleted since Findmall update broke all old links

Again, the problem is that as you get hotter on small gold the detector also acts more like a hot VLF than a PI. Building a hot PI is certainly possible but dealing with the problems that come along with doing so is a challenge.

When I was in Australia we did a little head to head hot VLF vs hot PI. The bottom line is the VLF got the tiniest shallow gold but the PI was able to hit a bit larger stuff deeper than the VLF could see. It takes the whole VLF vs PI thing down to a battle in the top few inches with both having strengths and weaknesses.

Link to post
Share on other sites

"I'd imagine the scd2300 will be a hot unit on small gold, probably on par with the 5000, shame about the fixed mono coil" 

 

Is what i was told by a guy who got to play with one in Western Australia at a Minelab metal detector demo day over the weekend, run by Gold Search Australia..
I've got an F3, it was built for a purpose, as is the sdc2300 patch hunting small gold. I think It'll be a great one for detecting creeks/streams.. can't see it being worth 4k asking price.

Link to post
Share on other sites
 When you turn power off that electromagnetic field collapses on itself and generates its own electrical signal.  (Faraday's Law)

And as you note, that's why the delay is needed. It is just that delay that has hindered PI detectors from seeing the smallest and most wiry gold. There is a brief momentary spike in voltage that occurs and that happens during the delay period. The weakest of signals from small targets are lost during this time - that's why the delay hinders the recovery of the smallest targets. Sometime a short while back Minelab published and patented a new method of dealing with the Faraday spike which will allow detectors using this technology to have a significantly shorter pulse delay. How short - don't ask me, I don't know, and don't ask me how they do it, I have a vague idea. But I think this is exactly what the MPF is - the same kind of general multi-period pulse length employed by previous GPX detectors, but done fast, meaning a shorter delay and capability to detect smaller gold. I think there is good reason for optimism.

Link to post
Share on other sites

Get the weight down to 3 lbs. +/- then I might buy it to detect "invisible" gold. I think I will stick with the 4500 for now.

Link to post
Share on other sites

The problem is that its hard to do lightweight and waterproof at the same time. Both the Garrett ATX and the up and coming SDC 2300 are based on military spec boxes, which make these machines hard and durable, but the military isn't as focused on lightweight.

Link to post
Share on other sites

Again, the problem is that as you get hotter on small gold the detector also acts more like a hot VLF than a PI. Building a hot PI is certainly possible but dealing with the problems that come along with doing so is a challenge.

When I was in Australia we did a little head to head hot VLF vs hot PI. The bottom line is the VLF got the tiniest shallow gold but the PI was able to hit a bit larger stuff deeper than the VLF could see. It takes the whole VLF vs PI thing down to a battle in the top few inches with both having strengths and weaknesses.

 

 

Thanks Steve for your reply and links in regards to my previous post.

 

One of the important questions I assume to be asked is how much of that battle as you say in the top few inches of ground would be won by this SDC PI over the most sensitive VLF and I expect the type of ground will have the say on that.

 

The battle for me is if the SDC2300 with its 8” coil can punch to depths greater on small nuggets in medium to severe mineralised ground than my GPX5000 in its most sensitive timing of Fine Gold with my 8” coil. That result I would have to rely on others to find out.

 

In regards to your VLF verses a hot PI an interesting observation from an interview between JP and Bruce Candy on air-depth test results and how accurate that result may be to what could be achieved in very mineralised ground then BC said the Smooth, Enhance and Fine Gold timings on a GPX can get within (98%) of their air-depth test result. BC then goes on to say a VLF in very mineralised ground may get only a quarter (25%) of their air-depth test result.

Link to post
Share on other sites

""The battle for me is if the SDC2300 with its 8” coil can punch to depths greater on small nuggets in medium to severe mineralised ground than my GPX5000 in its most sensitive timing of Fine Gold with my 8” coil.""

 

That is the question I am looking for the answer to also...detector question of the year!

 

BK

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
  • Similar Content

    • By rob baum
      I bought a house in meadview about 4 years ago.  Every couple months when I go there I try to get over to gold basin to do some detecting or drywashing.  It took me a couple years to find my first nugget out there and its been a couple of years since then and I havent found another.  I swing an SDC and I've read people have done pretty good out there with that model.  I find plenty of lead and boot tacks a inch or two down but not much deeper than that.   What settings are people using out there?  How deep down are people finding the gold?  Would I be better off with a  different model that can go deeper?  I'm not very confident in my abilities since I learned this machine on my own and have only found 2 pieces in the 4 years and dozens of times I've used it.  Any advice would be appreciated. 
    • By Gerry in Idaho
      Here's the 1st video Minelab USA did for TV.  You might know the English sounding dude from FL.
      What's interesting is we were able to see Minelab Mine Detector as it turned into a gold detector.
      The comments towards the end about seeing what's in the ground before you dig it, I'm still waiting.
      Do you feel, we'll see a detector that can actually see the item or at least the shape of it with any accuracy and if so how long out?
       
       
    • By PPP
      Hi!
      Another classic question,but i have a ctx3030 with 17inch coil and do mostly detecting in the saltwater.It goes deep and thats what i'm looking for,depth,,I know that SDC2300 is a PI machine and very sensitive to gold.But when it comes to depth comparison in saltwater and knowing the SDC2300 has 8 inch coil,then the question is which detector goes deeper?is it worth buying that expensive unit just for saltwater beahhunting? 
    • By Bear
      Glad to see Simon is back.
      I know there are previous posts about SDC battery compartment seal, I had problems with mine this summer.  
       
      Here is the background that I have posted about before.
      I dredge in an old cut that wasn’t cleaned that good into the bedrock.  The bedrock is a quartz muscovite schist that through frost shattering and dissolution is deeply weathered making it easy to dredge into for a couple of feet.  Because it is a cut the water is always murky and work is done by feel.  A couple of years ago I dug a big section that I thought was cleaned up.  Previously I seen a guy use an Excalibur to check where he had dredged so I took the SDC in.  There was targets so dredged deeper and recovered a couple more nuggets.  Now this has become standard practice.  
      This summer while changing the batteries there was water in the battery compartment.  I cleaned and dried the compartment.  Also cleaned the seal and the machine worked fine but I would like to change it.  Through a search nobody sells replacements?
    • By Lunk
      With the fantastic weather in the Rye Patch region during the month of October, I was chomping at the bit to get down there, but my summer job didn't end until the 30th. It still took me a few days afterward to get everything wrapped up, so I finally hit the road and met up with Gerry and friends at Rye Patch the following Tuesday. The detector training class we were scheduled to give that weekend ended up being cancelled, thanks to a winter storm that was forecast to move into the area on Friday. Needless to say, having only two days of optimal detecting conditions before being snowed out and forced to move on to Arizona was a total bummer.😞 Intent on finding a few bits of gold in-spite of the looming storm system and armed with our trusty Minelab GPZ 7000 gold detectors (and one SDC 2300 - also quite trusty, btw), we hit an old patch in hopes of digging up some previously overlooked yellow metal. Only two small nuggets were found after a couple of hours searching with four coils on the ground - not a very good start. It was then that I remembered another old patch nearby that I had completely forgotten about, it had been so long since I had been there. It wasn't a very good producer back in the day, but perhaps we would be able to find a few nuggets that the VLF and early PI machines may have left behind. Within minutes of hitting the ground, my good friend Chef Rusty and I both popped a shallow sub-gram nugget; not a bad start. Soon, everyone was digging good gold! My second target gave an obvious yet deep sounding signal response from the GPZ's stock 14” coil. I imagined it to be a three or four gram piece at a depth of 12” to 18”. Gerry noticed me digging quite an excavation and came over to capture the action on video. At a measured depth of 20”, the target was finally out of the hole, and as I held it aloft there was an audible gasp from the audience that had gathered to watch, followed by cheers and fist-bumps:

       
      After a thorough cleaning, the specimen weighed in at a whopping 40 grams - a totally unexpected and pleasant surprise! The nuggets kept biting sporadically for everyone the rest of the day, and the same was repeated the following day. Just goes to show that sometimes the ZVT tech can really ignite an old burned-out nugget patch. Much fun was had by all, and it really made up for such a short two-day detecting trip. Pictured below are my finds, including the 40 gram chunk, a couple nuggets at over 8 grams, and all the small bits, with a total combined weight of over 66 grams.
       

    • By Steve Herschbach
      Four used ones advertised on The Classifieds in the last couple days, one sold already. Seems like Gerry’s circle of people... you know something the rest of us do not know Gerry?

×
×
  • Create New...