considering making the raptor

[DOOLEY]

how do all,

considering making the raptor detector from ITMD,
have read the book cover to cover many times over,
ok,
ive not paid much attention the the LRL section !!
lol !!!
anyways,
she looks like a good one to play with,
nice layout,
looks quite similar to uMAX also.
after many many reads of both the proto-type
and the final design i have confusion brought on by
discrepencies in some of the wording.
so,
clarity is required.
a home made coil is also going to be used,
and will be set up as the design requires.
but,
Although many references are made to the coil having
To phase shift to the LEFT,
A few times it also mentions it has to phase shift to
The RIGHT,
That's the 1ST point that needs clearing up.

2nd point (s) to clear up,
In the proto-type section it states that the DISC
Pulse is to be located over the + of RX signal and set
For maximum dc.
And the GEB is to be set at
" the positive going zero cross point"
And then adjusted for zero volts.

BUT,

on the final set-up of the raptor on page 118
It says DISC is to be located CENTRALLY over +
Of RX,
But this would result in zero volts at Tp.
And,
GEB is to be adjusted to be "CENTRAL over possitive
Going zero crossing point of the RX"
BUT,
This will result in RX peak amplitude at Tp.

I've never been "into" cw vlf's,
But thought I'd give it a go,
Understanding how they work and the principles
Is VERY important,
But it's very hard to get my head
around the principles
With this conflicting information,
Poss many others will be struggling to
Also.
Poss to the point where they simply give up trying.

Have I made a mistake or am I correct that there
Are discrepancys ???
Many apologies in advance if it's my mistake.

Ps:
Have changed my mind that many times when explaining
To the missis regarding what
Part of the signal does what and how it works
And that I finally understand it,
Only to change my mind yet again that I reckon
I'm annoying the Hell out of her and becoming
Tedious !!!
LoL.
still,
Good that she's showing much interest as when
Finished she'll be the one swinging it.........

[kt315]

ive not paid much attention the the LRL section !!

thank you lots for that. I and another people did waste much time and nerve LRL was deleted. now as I did prognoze much english speaking people had went in forum. with LRL that
was impossible.

[Qiaozhi]

how do all,

considering making the raptor detector from ITMD,
have read the book cover to cover many times over,
ok,
ive not paid much attention the the LRL section !!
lol !!!

The LRL section is there for completeness, and hopefully it will save a few poor souls from having their wallets mined.
However, it also manages to upset three separate sets of people. The first group don't believe a word they read, as they've either been well and truly conditioned into believing that dowsing and LRLs can actually find treasure, and no amount of saying otherwise will ever convince them of the fact. The second group are the purveyors of such contraptions, and don't like it when the truth is told. The third group are those who would rather that dowsing and LRLs were not mentioned at all.
Anyway, it's not by chance that the LRL nonsense is located in Chapter 13.

anyways,
she looks like a good one to play with,
nice layout,
looks quite similar to uMAX also.
after many many reads of both the proto-type
and the final design i have confusion brought on by
discrepencies in some of the wording.
so,
clarity is required.
a home made coil is also going to be used,
and will be set up as the design requires.
but,
Although many references are made to the coil having
To phase shift to the LEFT,
A few times it also mentions it has to phase shift to
The RIGHT,
That's the 1ST point that needs clearing up.

For the Tesoro coils tested, and for the homemade versions, the phase-shift is always to the left for the concentric, and to the right for DD.

2nd point (s) to clear up,
In the proto-type section it states that the DISC
Pulse is to be located over the + of RX signal and set
For maximum dc.
And the GEB is to be set at
" the positive going zero cross point"
And then adjusted for zero volts.

BUT,

on the final set-up of the raptor on page 118
It says DISC is to be located CENTRALLY over +
Of RX,
But this would result in zero volts at Tp.
And,
GEB is to be adjusted to be "CENTRAL over possitive
Going zero crossing point of the RX"
BUT,
This will result in RX peak amplitude at Tp.

I think you've got yourself a bit confused, as both these descriptions are consistent.
The DISC sample pulse is positioned over the positive peak of the RX signal, so the sampled voltage will be at a maximum.
The GEB sample pulse is positioned over the positive-going zero-volt crossing of the RX signal, so the sampled voltage will be zero.
For example, if we take the GEB sample, as it is located over the zero-crossing it contains portions of the RX signal where it goes negative and where it goes positive. When centrally positioned, the net average will be zero.
Once you get to play around with the design, it will become clear that for practical purposes both the GEB and DISC samples are located slightly off from their theoretically ideal positions.

I've never been "into" cw vlf's,
But thought I'd give it a go,
Understanding how they work and the principles
Is VERY important,
But it's very hard to get my head
around the principles
With this conflicting information,
Poss many others will be struggling to
Also.
Poss to the point where they simply give up trying.

Have I made a mistake or am I correct that there
Are discrepancys ???
Many apologies in advance if it's my mistake.

Ps:
Have changed my mind that many times when explaining
To the missis regarding what
Part of the signal does what and how it works
And that I finally understand it,
Only to change my mind yet again that I reckon
I'm annoying the Hell out of her and becoming
Tedious !!!
LoL.
still,
Good that she's showing much interest as when
Finished she'll be the one swinging it.........

If you can possibly do so, first build Raptor using a commercial concentric coil. Attempting to build your own coil from the start will add another layer of complication.

[sinclairuser]

i fancied having a go at the projects in the book, but unfortunately two things have conspired against that, first is i was not quick enough getting a set of those boards off andy before they went(i can make my own boards for small bits but for projects like this i like proper boards), and second i could not find my copy of the book, it turned up floating in the flood water in our holiday place(bollocks).
so until i replace the book, i'm snookered, but to be fair knowing me i wont attempt it without a set of boards anyway.

[sinclairuser]

i fancied having a go at the projects in the book, but unfortunately two things have conspired against that, first is i was not quick enough getting a set of those boards off andy before they went(i can make my own boards for small bits but for projects like this i like proper boards), and second i could not find my copy of the book, it turned up floating in the flood water in our holiday place(bollocks).
so until i replace the book, i'm snookered, but to be fair knowing me i wont attempt it without a set of boards anyway.

actually thats a good point, the itmd boards should be available in the shop, they marry so well with the book.

[mschmahl]

I think you've got yourself a bit confused, as both these descriptions are consistent.
The DISC sample pulse is positioned over the positive peak of the RX signal, so the sampled voltage will be at a maximum.
The GEB sample pulse is positioned over the positive-going zero-volt crossing of the RX signal, so the sampled voltage will be zero.
For example, if we take the GEB sample, as it is located over the zero-crossing it contains portions of the RX signal where it goes negative and where it goes positive. When centrally positioned, the net average will be zero.
Once you get to play around with the design, it will become clear that for practical purposes both the GEB and DISC samples are located slightly off from their theoretically ideal positions.
If you can possibly do so, first build Raptor using a commercial concentric coil. Attempting to build your own coil from the start will add another layer of complication.

Is this only for concentric coil´s or also for DD´s?

What part´s we have to change to use commercial concentric coils from tesoro with 4 poles (the newer one e.g. tejon, lobo-st)?

[Qiaozhi]

Is this only for concentric coil´s or also for DD´s?

What part´s we have to change to use commercial concentric coils from tesoro with 4 poles (the newer one e.g. tejon, lobo-st)?

Raptor works with both concentric and DD coils. It is designed to use the 5-pin Tesoro coils with a TX inductance around 6mH and an RX inductance of around 6.5mH. The 4-pin coil coil types are not suitable.

[Qiaozhi]

i fancied having a go at the projects in the book, but unfortunately two things have conspired against that, first is i was not quick enough getting a set of those boards off andy before they went(i can make my own boards for small bits but for projects like this i like proper boards), and second i could not find my copy of the book, it turned up floating in the flood water in our holiday place(bollocks).
so until i replace the book, i'm snookered, but to be fair knowing me i wont attempt it without a set of boards anyway.

Well ... we cannot have an active Geotech member without his copy of ITMD. If you pay for the P&P, I'll find you a replacement.
Please send me a PM.

[DOOLEY]

Thank you George for your explanation,
It all makes sense now.

Regarding the LRL's
Firm believer that two bits of bent wire rod can
Find water pipes and electric cables,
But that's where it ends !!!
That's my position cleared up then.
LOL.

so,
The sample is an AVERAGE of the signal
Taken during the "on" time of the sample
Switch,
As I suspected by the diagram.

Would it not be better to have a direct sample
Similar to a PI detector which would be more
Accurate than an AVERAGE ???

My recent thoughts were to have a peak
Detector JUST for amplitude of RX,
Purely for ferrous // non- ferrous
Indication,
Quite easy to implement.

Then to measure phase shift by time to
Voltage conversion,
Simply by marking both TX and RX zero
Crossing points,
And,
Either using a timer,
Or simple capacitor charge over time
An accurate measurement of phase can
Be achieved.
Would certainly be more sensitive,
Would this be a more accurate way of
Target discrimination ???

Also,
A ground balance technique based
Purely on phase shift,
Which could,
I think,
quite easily be automatic.

[Qiaozhi]

My recent thoughts were to have a peak
Detector JUST for amplitude of RX,
Purely for ferrous // non- ferrous
Indication,
Quite easy to implement.

Then to measure phase shift by time to
Voltage conversion,
Simply by marking both TX and RX zero
Crossing points,
And,
Either using a timer,
Or simple capacitor charge over time
An accurate measurement of phase can
Be achieved.
Would certainly be more sensitive,
Would this be a more accurate way of
Target discrimination ???

Try it and see. It would make an interesting experiment.
Although I suspect the amplitude (peak detected) signal will be affected adversely by the ground matrix.

[nnetley]

Gerber files for raptor.

Does anyone have the gerber files for this board?

[dbanner]

A stock coil gives best guarantee of success. When you finally get around to adjusting and calibrating the circuit for proper functioning of ground balance and correct discrimination range on the front knob, an appropriate stock tesoro coil will SAVE YOU BIG HEADACHE.
After you've got the detector working right with the stock coil, you can have a try building different coils(DD or concentric).
The phase offset and null of a self-made coil is of paramount importance(at the appropriate resonant frequencies), and is no easy feat. Especially construction of concentric coils, which is a skill unto itself. It takes practice and constant tinkering to get it just right. Not to mention the sheilding requirements.

[dbanner]

I have built several DD coils, a few of them that actually work good. My adventures in concentric coils have mixed results. But it never really feels like it gets easier.
I have come around to the view that buying a stock coil is best.( worth paying the money)
There are some people who think you can wind a DD coil, wrap in foil and pot it in anything and presto! NO! NO! NO!

[Math]

Received ITMD from my brother for my birthday this month.. its excellent!
Thanks to everyone who has been part of it, ive learned so much more already.
Dooley id like to build the Raptor too.. i understand the phases as..
- All Metal/ GEB channel setup your square TX chop pulse or ‘A.M. detection window’ centred over the RX zero crossing points
ie. this chops through the peaks of the RX waveform.. with slight offset for ground balance.. this channel detects mainly phase shifts
- Disc channel setup 2nd TX chop pulse ‘Disc detection window’ centred over RX peaks ie. chopping points at RX zero crossings.. this detects mainly amplitude changes.. as discrimination (chop pulse) is changed this produces more phase effect to this channel.
- For ferrous/non ferrous targets.. Phase shifts left/right or Amplitude changes up/down are dependent on the initial coil null setup,
as is the initial RX to TX phase difference.. this determines which side of RX wave (leading/trailing) your GEB window is on and which RX peak (positive/negative) your Disc window is on
Hope this helps..

[dbanner]

Received ITMD from my brother for my birthday this month.. its excellent!
Thanks to everyone who has been part of it, ive learned so much more already.
Dooley id like to build the Raptor too.. i understand the phases as..
- All Metal/ GEB channel setup your square TX chop pulse or ‘A.M. detection window’ centred over the RX zero crossing points
ie. this chops through the peaks of the RX waveform.. with slight offset for ground balance.. this channel detects mainly phase shifts
- Disc channel setup 2nd TX chop pulse ‘Disc detection window’ centred over RX peaks ie. chopping points at RX zero crossings.. this detects mainly amplitude changes.. as discrimination (chop pulse) is changed this produces more phase effect to this channel.
- For ferrous/non ferrous targets.. Phase shifts left/right or Amplitude changes up/down are dependent on the initial coil null setup,
as is the initial RX to TX phase difference.. this determines which side of RX wave (leading/trailing) your GEB window is on and which RX peak (positive/negative) your Disc window is on
Hope this helps..

Precisely why a stock coil is best. Because of the initial coil null setup, it is absolutely critical, and no easy thing to get right when doing a self made, especially when you have to keep a critical eye on the resonant frequencies of the TX/RX.