Riddle me this!

Many years ago there were many great minds over on FM, one was Shaun on the Sovereign/Excalibur forum. He made a few "Afterburners" for the sovereign. I found I could hear/measure the send field on the excalibur with a 2463 audiosears speaker. (Video under pics) Depth increase was 3 to 4 inches, and it worked great on the open beach, except in the saltwater. To much power and it sucked power. 3 Li-ion 18650 2200mAh 2 hours run time.

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Manticore FCC info.
Enjoy.

Did anyone get past page 1? Here are all the tests that were performed (p6):
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15.203 simply says the detector coils must be unique to the detector. Somewhere there is another rule that says all testing must be done with the largest available coil.
15.205 is a list of keep-out bands, mostly military.
15.207 is for AC plug-in operation. It doesn't apply to the detector but would apply to, say, a battery charger. Likely the charger is tested separately.
15.209 is for the actual detector operation.
15.247 is all Bluetooth.
15.215 is to ensure you don't generate interferers in other particular bands.

Here are the tests done for the Goldbug 2:

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Same sort of tests. Usually detectors are also tested for unintentional radiation under 15.109, for example all the digital noise that is generated on the PCB. The Goldbug 2 uses a crystal and some digital circuitry (no micro) so it had to be tested for this:

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I'm surprised this does not show up in the Manticore tests but it could be a separate document, as it is for the Goldbug. Or, it could be their test lab interprets the rules differently. Sometimes different labs insist on different rules, kinda like taxes and CPAs.

I don't know why people get all wrapped up in this topic as it's pretty irrelevant. But hopefully this sets the record straight once & for all, or at least until the FCC rewrites the rules.
 
I think what most people are looking for is Minelab, or somebody, to explain how they are marketing the idea that the Manticore has 50% more power to the ground. Seeing a lot of FCC regulations doesn't give the answer I think people are looking for. Maybe a bit gunshy after hearing for years about FSB transmitting 28 frequencies simultaneously, only to find out in fact it was just 2. Buyers just aren't as openly excepting claims that can't be proven.

The fact the Manticore is doing the trick isn't being called out.
 
Well, marketing mumbo jumbo aside. I think it's been made clear that there aren't any FCC limits preventing 50% (or 500%) more power being used to generate the coil magnetic field. Yes, there is a limit. But there's a lot of headroom left in that limit.

The engineer on the project, Mr. Lawrie has stated clearly that Manticore uses 50% more "power" (sorry Carl!) in the coil. We know Manticore has twice the battery capacity but much shorter run times than Equinox. We know that if Manticore does indeed have 50% more "power" that equals only a 7% increase in depth, at best. Prove or disprove that in the wild, I dare you.

I obviously don't actually know. But I'm inclined to believe Manticore probably does do that. I'm not yet convinced the drawbacks associated are worth it. Might be in some situations, not in others. Don't know.

But continuing to bring up CB radios and "watts" and such seems to be utterly letting the meat of the issue just fly right by. With more Manticores starting to ship now this soap opera is just getting started. It won't end soon. I'm pretty sure I just don't care anymore.

- Dave
 
I'm sure what Mark is doing is using lay-terms that people can relate to. Anyone who's ever watched Tim "the Toolman" Taylor knows what More Power means. But Tim never discussed what more ampere-turns means, or more B-field strength.

I suspect what Mark really means is that Manticore has a 50% stronger TX B-field. This can be achieved with 50% more coil current or 50% more turns in the TX coil, or some combination. In a detector with user control over the TX current (like the White's V3) you can decisively demonstrate what this does for target detection. It ain't a whole lot, but like the old man who pee'd in the sea said, every little bit helps.

From a strictly technical view, metal detector transmit "power" makes no sense because, in most designs, the power is mostly recycled. Including MF designs. That is, you can have 500mA of coil current but the TX circuit only consumes 25mA. Unlike RF antennae the detector coil does not emit RF power, it only produces a local magnetic field. However, real power is consumed by target eddy currents, but it's not much. This is why it also makes no sense to talk about FCC power limits on detectors. They don't really emit power.
 
I have a Manticore, and have taken it to two places I consider hunted out that once produced a lot of very deep edge of detection silver with the Equinox. These places have had many different detectors over them including the D2 and the Legend. One spot has the mildest ground I've ever hunted. It's basically sand, and some of the coins I found there were at a depth you literally just heard the slightest whisper with the Equinox max volume. In two trips hunting about 6 hours total I found zero silver and two or three edge of detection Wheat Cents. The Wheats were very deep, but I can't say they were any deeper than what I have found in the past with the Equinox. There was a buddy hunting with his Equinox 900 with me on one of the hunts. He to found a few very deep Wheats, but no silver.

Another spot is clay and more mineralized. This spot went from basically hunted out to producing again when I first got the Equinox. The Manticore has been to this spot twice, also for roughly 6 hours total. The same buddy with both the D2 9" and the Equinox 900 was there for one 3 hour hunt. No more silver and one deep Wheat Cent for the Manticore. No silver for my hunting buddy either. So far I have yet to see a noticeable depth advantage with the Manticore over the Equinox 800 or 900. It's definitely as deep, but honestly there may be no more detectable silver at these two places. My guess is what is left is either seriously mask or it could be there is just so few left it would take covering every square inch to find one.
 
Like Minelabs FBS, what we do know for a fact is it works. Knowing the details is one thing, but knowing what it can do is what relly matters. I don't care if it was using only 1 frequency as long as it does what it does. I still use the E-Trac and don't care if it was all hype about the 28 frequencies, it does what no other detector I've owned can do and that is what really matters.
 
Once you get through all the jargon that can be used to confuse the average user, this is where I got my info when you try and nail it down to simple terms.

Several of the FCC part 15 rules govern the transmit power permitted in the ISM bands. Here is a summary of those rules: Maximum transmitter output power, fed into the antenna, is 30 dBm (1 watt). Maximum Effective Isotropic Radiated Power (EIRP) is 36 dBm (4 watt).
 
The Dad of my best friend when growing up was a television repairman. I learned to degauss color TVs with my homemade degausser, and I degaussed the heads of my recording equipment. I also have my HAM radio license which takes a fair knowledge of RF to pass, so I am no total stranger to RF/magnetic function. Just seems to me, like usual, people try and make something simple difficult to fit their agenda. We really are just concerned with the amount of AC power being put into the transmit coil.
 
Once you get through all the jargon that can be used to confuse the average user, this is where I got my info when you try and nail it down to simple terms.

Several of the FCC part 15 rules govern the transmit power permitted in the ISM bands. Here is a summary of those rules: Maximum transmitter output power, fed into the antenna, is 30 dBm (1 watt). Maximum Effective Isotropic Radiated Power (EIRP) is 36 dBm (4 watt).
This would apply to, say, the Bluetooth radio in the detector (2.4GHz), but not the detector itself (2.6kHz - 40kHz). Different bands are tested differently, and to different limits.
We really are just concerned with the amount of AC power being put into the transmit coil.
Then the correct answer would be "nearly zero." Metal detector search coils are resonated so that their energy is recycled. That is, the power needed to create the magnetic field is almost 100% recovered when the field collapses. The only power loss is in the resistance of the coil.

As I've said, it makes no sense to talk about "transmit power" in metal detectors. They don't work like a radio.
 
The Dad of my best friend when growing up was a television repairman. I learned to degauss color TVs with my homemade degausser, and I degaussed the heads of my recording equipment. I also have my HAM radio license which takes a fair knowledge of RF to pass, so I am no total stranger to RF/magnetic function. Just seems to me, like usual, people try and make something simple difficult to fit their agenda. We really are just concerned with the amount of AC power being put into the transmit coil.
N2VHI, AAR2NNT
 
This would apply to, say, the Bluetooth radio in the detector (2.4GHz), but not the detector itself (2.6kHz - 40kHz). Different bands are tested differently, and to different limits.

Then the correct answer would be "nearly zero." Metal detector search coils are resonated so that their energy is recycled. That is, the power needed to create the magnetic field is almost 100% recovered when the field collapses. The only power loss is in the resistance of the coil.

As I've said, it makes no sense to talk about "transmit power" in metal detectors. They don't work like a radio.
KD0CWQ

So they had this limit, pertaining to wireless, even before there were wireless headphones? We can use all kinds of technical jargon to avoid what I see as a simple question. In the end, when that coil is run over an electrical conductive meter, what is its reading?

I think, dodging all the technical BS, you can measure the eddy current output of the coil with a conductive meter to compare power to the ground. After all, it is this current that excites the metal targets that in turn put out the strength of their return current then measured by the receive coil.

What I find interesting is the lack of discussion about the importance of the receiver coil. After all, it doesn't matter if a detector can transmit 10' in the ground if the receiver coil can only receive a pulse at 5". Don't we see tons of air tests to showing how a detector, and adjustments, can increase, or decrease, the output of the coils? Should be a simple measurement in there somewhere.

All respect due, I have never let someone's title or letters behind their name keep me from questioning something until It feels right. I've seen total idiots with master's degrees, and I've worked with many high-level technicians that really had a rather limited amount of knowledge. Don't take it personally. Just looking for answers.
 
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I think, dodging all the technical BS, you can measure the eddy current output of the coil with a conductive meter to compare power to the ground. After all, it is this current that excites the metal targets that in turn put out the strength of their return current then measured by the receive coil.
The coil produces an AC magnetic field which you can measure with a magnetic field meter and get a real reading in Teslas. A typical VLF might be around 25µT at the center of the TX coil whereas a PI might be 10 times higher. The RX coil plays no role in TX field strength but obviously does in depth of detection.
 
The coil produces an AC magnetic field which you can measure with a magnetic field meter and get a real reading in Teslas. A typical VLF might be around 25µT at the center of the TX coil whereas a PI might be 10 times higher. The RX coil plays no role in TX field strength but obviously does in depth of detection

Thanks Carl. I just don't see why more attention isn't put on the receiver side as it seems to play just as important a part in detecting depth as the receiver side.

Another thing I've wondered is about frequency and recovery speed. Does frequency affect recovery speed to a point that it needs to be considered?
 
You're right, the RX side is just as important as the TX, maybe more so. Most of the gains made in improved sensitivity in the last 10-20 yrs have all been on the RX side. But this thread veered off into the realm of TX "power" and FCC rules, which have nothing to do with the RX.

Frequency should not affect recovery speed. Recovery speed is dominated by the motion filters and the way the audio is generated.
 
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