Is it a new fisher coming out

I say this with all seriousness.

I would like to see an affordable,(to the everyday detectorist), ground penetrating radar type unit with a screen. A viewable screen where the actual item could be seen. i.e. size. In this type of detector there would be no need for
metal detecting capability, although I believe it could be incorpoated,and it's my opinion that the depth could well exceed any current unit. Of course the technology exists today as we know, but can it be applied to our hooby,and at what cost.

Wouldn't it be awesome to say, "There's a U.S. belt plate at 22" right here."

Now, today's ground penetrating radar to my knowledge takes an expert to understand and interpret what is seen on the screen. I'm also not sure about the effects of ground mineralization on a unit like this, but I'll bet you it doesn't play a big role in the restriction of depth on this fantasy unit.

And while we are at it can we relate this unit with a depth finder on a boat with it's picture possibly? And, we all know water is a much different medium than dirt,but,saltwater properties are well know in their effects on current metal dectectors.If oceanographers can find sunken ships at great depths in this medium with sonar,some form of ultimate depth (36") ground penetrating radar detector should be able to be built,and made affordable and available at some point.

Ken

GPR does exist. Key = 'affordable'.

Humm sounds cool,I'm sure without the FCC regulation 3" or more wouldn't be to much of a problem for a wizzard like Dave johnson... I bet that booger would be expensive....
Tom, dont these manufacturers have perimeters they have to stay with in, concerning power and freq Drift...



Edited 1 time(s). Last edit at 01/19/2009 11:21AM by liquid1.

Depth has nearly nothing to do with (TX) transmit power. It is nearly all in the (RX) receive SENSITIVITY. Last CZ I measured; TX power presented 27mW. Max allowable is 100mW.

NASA-Tom Wrote:
-------------------------------------------------------
> Depth has nearly nothing to do with (TX) transmit
> power. It is nearly all in the (RX) receive
> SENSITIVITY. Last CZ I measured; TX power
> presented 27mW. Max allowable is 100mW.

So Tom, is it fair to say that not as much transmit power is needed to penetrate into the ground to a depth of say 9" versus the amount of power needed to return the signal from that same depth?

And, if this is the case, then detectors if given more TX transmit power, say 60mW
could penetrate further than a signal could be returned?

Meaning, we have the capability to to get deeper than we currently realize but can't hear the return signal?

No, no. Think of it as "Inductive Coupling". It is not actually a signal 'bouncing' back to the coil and needing ample mW to do such (like radar); rather, the disturbance of a (otherwise) inductively balanced electromagnetic field (in the presence of a detected metallic object). If the electromagnetic signal can penetrate the dirt (bad dirt or otherwise) and reach the metallic target, this is all that is needed, , , the inductive balance is then 'disturbed' // 'warped' and the electronics will detect this imbalance (sometimes called interference). The phase shift angle differential is primarily what dictates conductivity of the metal and a ID is then determined/generated (primarily) by this phase shift delta (change). Sometimes a stronger TX signal is similar to running high-beams in fog. I know I have reported this info (maybe in greater detail) in a previous thread.

On this same subject; When a metal detector is turned on..... it is at a constant TX (transmit) power. When you boost the Sensitivity control to max,,,,,,,,,,, the TX power NEVER changes; only the "Sensitivity"..... sometimes known as 'receive gain'...... is boosted. This has NOTHING to do with TX power. Slightly more technical; the threshold baseline is driven lower/deeper "into the noise"....... which allows the faint signals to be heard (sometimes with the help of audio-boost circuitry). Only in extreme remote/unique/extenuating circumstances does additional TX power help anything. And RF energy dissipation rate is inversely asymptotic.

Food-for-thought: If a high speed car passing in front of the coil can be detected to a range of... say 8-feet........... this means that the electromagnetic field is 'sensing' (reaching) 8-feet. Now.... if you pass a dime 8-feet in front of the coil.......... ((((you already know that the electromagnetic energy reaches (senses) this distance))))............ what would it take to detect this dime???

Tom

So.. a detector with both a sensitivity adjustment and a gain adjustment (IE. Explorer) is increasing the receive strength with the sensitivity and boosting audio with gain?

In your dime analogy, I'm assuming filtering out the noise on an 8' coin would be nigh impossible unless you were detecting a place so remote that a coin wouldn't be there. Is that accurate?

Also could the uber sensitive F75 be unusable regionally based an un-filtered noise source in that region?



Edited 1 time(s). Last edit at 01/21/2009 04:59PM by Shambler.

A bigger dime. The car has more surface area, hence it is easily detected from a greater distance due to its volumn.

Or if the dime must remain its original size,then you need the ability to add more sensitivity, (receive gain), without subjecting that same sensitivity to interference.

Just like my CZ-3D achieves max depth at 4 3/4 sens setting. I have room to go up, but the question is way can't I increase sens to achieve greater depth.

I think that's been answered above. Outside interference won't allow it.

So should the in this case, (West Texas/Fisher) look at coil technology as a way to gain a better receive gain signal. The head, or detector brain has the capibility to transmit/receive/use, more sens, but because of outside interference it can't be used.

The question should be, what can we do to allow full sens use for greater depth detection without subjecting the curcuits to interference.



Edited 2 time(s). Last edit at 01/21/2009 10:20PM by Kas.

I do not have blueprints to the Explorer, yet I surmise it functions in a similar fashion... as on the F-75. Sens is similar to a volume control (to a certain extent) and Lowering Disc from '5' to a setting of '4' (for example) is akin to lowering squelch. The F-70 also employ's these functions, but in a slightly different fashion. Same with other brands/units.

True, , , in order to detect a dime at 8' would be nearly impossible (with current technology) due to the requirement to boost Sens so high...... way-beyond/deep-into the 'random atmospheric' noise levels.

And yes, I can attest that the F-75 could indeed utilize a "lower squelch baseline" and higher Sens levels then currently available...... but only for locations that are exceptionally sans RF-EMI. I could have used this function/feature (had it been available) in several locations thus far.

I have always felt that some form of phase-balanced tempest shielding should be engineered above the coil......... so as to further isolate the coil from external RF-EMI. This would place further focus on ground-signals only; hence, allowing greater gain settings (above current availability) before atmospheric noise becomes a problem again.

Tom

Tom - can you take a second and lightly explain what is happening with ground balancing in relation to above? Also, do you know what the Explorer models are doing with noise cancel?

I would like to see a lot tighter nickel notch like on the 3D for people like me who don't like to dig every target. The F5 notch was way too big and accepted too much trash.

Yes now that the vision is out with all the glitter and color I would love to see fisher get a lot more depth like a lot, did I say alot? And yes tighter on nickels and maybe two freq that can be used independently. And some new coil like a white's bigfoot...how about a new F-CZ we don't want fluff give us tough.

Let white's continue on the DFX platform and have fisher do something that they do great...speed, depth, unmasking and????

LowBoy

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Sometimes noise-cancel is done by 'clipping' the spikes of very weak signals..... on some units. On other units, it can be as simple as a minute' freq change.

Without asking for radical changes to the technology, how about:

1 - ... a removable SIM card that contains the main processor. That way you buy a new 'card' as an incremental improvement for a few years until a new platform is developed. RFI issues may be an issue as clock speeds increase.

2 - Add a USB port for enabling firmware upgrades, as found today in many high end electronic devices.

3 - Allow a minimal visual screen if so desired showing only a big icon or VDI # so as all the processing power can be applied to maximize recovery speed. This would then become a turbocharged Minelab Sovereign, one of my favorite machines.

4 - Reduce weight further by using graphite for the tube sections. Use carbon fiber for other parts.

5 - Use gold plated connectors between the coil wire and control box.

6 - Allow for optional audio functions to maximize the amount of information you can hear rather than see (opposite of White's Vision)

The old Barron had upgradable modules. The thought is still valid. But a removable SIM card is a bit easier to pirate. This may not be a good choice (corporately).
---- The clock speed vs. the size of the VDI screen are completely independent of each other.
---- Not sure how much more audio functions would be needed......... especially since many folks hunt with monotone...... or 4-tone. I would not mind having one extra audio tone that was 'user assignable'. I would like to have.... say: VDI readings of 16 - 21 to give a completely different audio tone from the avail 4 tones. Or maybe 16 - 33 would be the selected window. In any case, , , one extra tone available for the user to assign to whatever his preference.

I wonder how much faster the recovery speed could be on the Vision if the processor were not tasked to draw three simultaneous color curves on that high resolution screen while storing additional data to draw other screens. There has to be a "cost" for all that extra computation.

The programmable tone would be a nice feature but I'm talking about new audio options that I've never seen like an audio boost and/or smoothing (extended time) for weak signals having a high VDI ID.

My small concentric coil on my F75 does an excellent job IDing bottle caps. Could a loop be made with both geometries that simultaneously switches back and forth at a KHz frequency to gain the benefit of both coil geometries?

I like the idea of better shielding the top of the coil. Maybe the sensitivity of the reciever circuit could be improved?

You guys work on the electronics. I would just like to be able to swivel the screen right or left about 20 degrees depending on if I am swinging with my right hand or left. Ergonomically it would help the neck pain as well as keeping your arm straighter. I hate having to contort my arm and crane my neck to see what is on the display. And speaking of the display – how about an antiglare screen? Would that be too technical to come up with?

Cuniagau

“Never approach a bull from the front, a horse from the rear or a fool from any direction.”

be able to swivel the screen right or left about 20 degrees depending on if I am swinging with my right hand or left. Ergonomically it would help the neck pain as well as keeping your arm straighter. I hate having to contort my arm and crane my neck

A heads-up-display in a pair of sunglasses would be the best

Interesting concepts.