White 3900D

[dbanner]

OKey. MAIN ISSUE THERE IS NOT THE PHASE SHIFT MENTIONED IN THE PATENT.
GREAT DISCOVERY AMIGO.

second issue. can you give me a patent of whites WITH/ON coil phase shift?

Simple amigo, just measure on oscilloscope the Rx/Tx waveforms of a Whites bluemax coil with your famous coil tester. Tell us if you see a residual phase shift.

[kt315]

OKey. MAIN ISSUE THERE IS NOT THE PHASE SHIFT MENTIONED IN THE PATENT.
GREAT DISCOVERY AMIGO.

second issue. can you give me a patent of whites WITH/ON coil phase shift?

[dbanner]

Koliaj deleted a cap on RX and got same result. you have to learn russian and russians forum.
i had gave a link. find me out phase shift mentioned in the patent.

https://www.youtube.com/watch?v=8Hs78GXUkFE

what type coils you see in this video? STANDART 6.59Khz. NOT 6B COIL. so your point is a fantazy.

A few points here.

Firstly, the patent US4293816 describes the physical construction of the concentric coplanar coil design, along with the theory of balancing, due to the buck(feedback) coil arrangement. It does not mention signal phase because that was not the intention of the patent. It's intention was to demonstrate the balancing of a coil so constructed, with minimum residual voltage, by means of a feedback coil.

Secondly, it is mentioned in the patent that the operating frequency of the oscillator is 5.125kHz, and thus the Tx coil is tuned by means of a parallel capacitor for resonance of 5.125kHz of the oscillating Tx circuit.

Thirdly, the Rx coil in the patent, based on Qiaozhi's coil calculator (Brooke's equation), has an inductance of around 11.8mH.
If you tune this Rx coil with the 27nF cap stipulated in the patent, you get a Rx coil resonance of 8.9Khz. Right away you see there is "off resonance between the Tx and Rx coils " when coils are balanced. THIS WILL RESULT IN A PHASE SHIFT of the Rx voltage with respect to the Tx. So a phase shift, although not expressly stated, is implied.

Lastly, I believe there are only two conditions which result in zero phase shift, these are 1: when Rx is non-resonant, and 2: when Rx and Tx are at equal or "full" resonance.

[kt315]

15 maxima blue coil. on RX part we see 33nF cap.

[kt315]

Koliaj deleted a cap on RX and got same result. you have to learn russian and russians forum.
i had gave a link. find me out phase shift mentioned in the patent.

https://www.youtube.com/watch?v=8Hs78GXUkFE

what type coils you see in this video? STANDART 6.59Khz. NOT 6B COIL. so your point is a fantazy.

[dbanner]

By the way, a coincidence of the phases (which ocurrs at 180 degrees) is still considered a phase shift.
With a non-resonant Rx coil, there is no phase shift (at zero null), and the phases of the Tx and Rx coincide.

So balancing the coils "off resonance" creates an inherent phase shift.
It is plain to see we are talking about the 6B and bluemax coils.

THE 6B COIL FOR THE 3900 WAS ALSO USED ON FULL DISCRIM. UNITS such as the 5900 and 6000DI. So your point is moot.

[kt315]

BECAUSE THE COILS ARE SO BALANCED TO SUCH PARAMETERS, AND NOT TO PERFECT NULL.
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because all around you is developing permanently. in 80s years whites HAD NOT KNOW (CAN NOT) about
MODERN coils NOTHING. then later they did XLT and XLT coil. we know it like RAINBOW coil.
but anyway it is OLD tech.
open whites patent US4293816 and you will see NOTHING about the 'phase shift'.
NOTHING. no one brief comment.
you do ALL-METALL schematic with some DISC tuning. whites worked out some new thing on current production.
in plan it did keep to release 5900 pro sl. 3900 was just some stage in experiments.
as just they got a result they rewent on 5900.

[dbanner]

whites had fully changed the coil balancing methodology. i told that many times. there is NO PRIMARY RX vs TX phase aspect.
NOT EXISTS. there is sure FULL ZEROING, to microvolts residual value on RX.
you CAN NOT set the phase if you see on your o-scope screen NOTHING, just something of smeared line on the noise level.

I refer to the Tx/Rx tuned resonances. If both Tx and Rx are tuned to the same resonances, there is maximum sensitivity of the coil (air test), but there will be poor performance due to the dynamic effects of the soil.
However, if the Rx is tuned to resonance at a specifically selected "off resonance" frequency, There is increasing phase shift and the dynamic effects of the soil is weaker by several orders of magnitude compared to the static effects.
There is a phase shift between the the Tx and Rx in Whites older loops. BECAUSE THE COILS ARE SO BALANCED TO SUCH PARAMETERS, AND NOT TO PERFECT RESONANCE.
The reason for the frequency seperation is not so clear to me, but there MUST BE A GOOD REASON.
This is question for expert engineers and for much testing and research, which is beyond the scope of the simple diy hobby man like myself.
I only wish to know the parameters of coil construction, and what to look for on the scope while tuning and nulling.

[kt315]

GB to this schematic is nonaddable.

[sayan1345]

Hi DB
can you ad the GB to this circuit

[MartyJ1963]

Ok DB,,,Thanks,,,Just wanted to know how things were with the PCB before I started etching,,,You said to wait so hopefully all goes well with your board,,,Regards,,Marty.

[dbanner]

Hi all,,,,Any progress yet DB? Thanks,,Marty

.Not yet, things are moving slowly.
It is not so easy for me these days, I have a lot on my plate to deal with at the moment. Hopefully I'll have something to show on the weekend.

[kt315]

whites had fully changed the coil balancing methodology. i told that many times. there is NO PRIMARY RX vs TX phase aspect.
NOT EXISTS. there is sure FULL ZEROING, to microvolts residual value on RX.
you CAN NOT set the phase if you see on your o-scope screen NOTHING, just something of smeared line on the noise level.

[MartyJ1963]

Hi all,,,,Any progress yet DB? Thanks,,Marty

[kt315]

good start point to begin learning non-motion schematic https://www.ebay.com/itm/Metal-detec...4df4%7Ciid%3A1