Interview, David Johnson and John Gardiner

[Davor]

I was quite successful in building a sonar with chirp excitation. It is doing exactly the same job as the pulse sonar does, but with a benefit of frequency response equalisation within a frequency range of interest. In essence, it can perform just as a brick wall filter, only incredibly simpler.

Regarding the ferrous materials noise, it is the Barkhausen effect that does it, see https://en.wikipedia.org/wiki/Barkhausen_effect
It is not the same in various materials. Allegedly some anti-theft systems use it, only I'm not into these and I can't say.

[Sean_Goddard]

Regarding the "requirement" to boost the transmit signal to get more depth and in relation to sending video down a narrow BW telephone cable. I'm thinking compression (YES I KNOW) but what I'm hinting at is maybe it is possible to increase depth by using a different form of return signal analysis. Some people claim they can "hear" the "noise" iron makes ("Fuzzy" signal) OK so WHY can't a machine do this?

I propose there is FAR more information IN the Rx signal than is presently being used or, in most cases understood. Aziz seems to be making the biggest headway in this area. I'm going to look at an FFT of and Rx signal with respect to a Tx signal using an IFT signal generator (PC based) then see how different targets react. I dont think it will be necessary to balance the coil as this can be done in software. I shall be looking for "distortions" in the returned spectrum.

I'll post the results on the forum when I get chance. Who knows, maybe I'll find something new or more likely just add to what has been already done..

BTW what happened to the "chirp" detector, no schematics and no progress so maybe it's a "goer" and the person decided to keep it to themselves.

[mikebg]

What is Johnsons noise?

Johsons noise is the noise generated by Dave Johnson.
Here is the Johnson noise generator:

[WM6]

Hope it doesn't change!

Do not worry, it will not!

The safest solution for deep gold.

[simonbaker]

Hi Ivconic,

you seem not see the value of (theoretical) knowledge. BTW, I wasn't offended by you nor I have to show you what I have achieved so far.

This site is known for discussing ideas as well. What's wrong with it?

Aziz

This site is interesting because of several types of people -- the builder/layout people who give us real kits to build, and idea people who try new sometimes whacky things, theory people who try to explain why things happen and help guide idea people into more fruitful areas. Some people are a little of everything. Also the "colorful" people who are outspoken and keep the site very entertaining! Hopefully there is respect underneath it all and a drop of humility so our egos can lick their wounds and come back for more rounds -- well I try anyway.

Hope it doesn't change!

Cheers,

-SB

[WM6]

This time, I won't publish the results and let this task to you all.

Sure you won't Aziz, cause there is no applicable results at all.


But you have potential and chances equal to any other here.
What will be under this, we will see in next 20 years.
In meantime try to be real. I wish you the best.

[ivconic]

No need to quarrel among such distinguished members of this forum.During long time following your work I think we need a little theoretical discussion, although this is a DIY forum. I think that manufacturers deliberately limit the depth of the detector and therefore we should find a new way in which the detectors worked. This forum is a great place for that.Yust go for it !

Sure, i agree.
I will keep my thoughts further just for myself.
Obviously is not popular nor "payable" always to talk fairly and honestly...

[ivconic]

Hi Ivconic,

you seem not see the value of (theoretical) knowledge. BTW, I wasn't offended by you nor I have to show you what I have achieved so far.

This site is known for discussing ideas as well. What's wrong with it?

Aziz

You said that, so those are your words.
Thanks!

[PERTINAX]

No need to quarrel among such distinguished members of this forum.During long time following your work I think we need a little theoretical discussion, although this is a DIY forum. I think that manufacturers deliberately limit the depth of the detector and therefore we should find a new way in which the detectors worked. This forum is a great place for that.Yust go for it !

[Aziz]

Hi Ivconic,

you seem not see the value of (theoretical) knowledge. BTW, I wasn't offended by you nor I have to show you what I have achieved so far.

This site is known for discussing ideas as well. What's wrong with it?

Aziz

[ivconic]

Hi ivconic,

should we build a 101 floor building and hope and pray, it won't collapse?
A good engineer calculates the problem thoroughly before realising it.

Ain't it better the know more?

Aziz

Comeon guys! Do your own proof to see, whether you get the same result (challenge offer).

In the mean time, I'll do an analysis for a ground loop coil configuration. This time, I won't publish the results and let this task to you all. I bet it would take another 20 years.

So expected!
My previous post kind a offended you and now you "won't publish..." any more?
Who is childish here?
"No more.." - as i told you; even so far i didn't see 1% benefit from so much theories, not only yours but from few other people too. Meaning nothing bad of course.
To make a building you need to know how to make it, collect material and, finally once for all to start to build it!
20 more years will pass until we see here at least ONE of your practical design.
Nothing bad in that too.
You simply chose that way, nobody have right to blame your choice.....but
BUT THAN stop with washing our brains here with something pure theoretical.
Aside that, everything else is quite cool! No need to be offended by no means.
This is forum and we just are confronting our opinions and attitudes.
Regards!

[Monolith]

just use this

I don't think this is legal in most places.

Monolith

[Aziz]

And my favorite hobby is to print on paper such claims and theories and later to use that paper in such purposes!

Feeling is tough to describe!

Hi ivconic,

should we build a 101 floor building and hope and pray, it won't collapse?
A good engineer calculates the problem thoroughly before realising it.

Ain't it better the know more?

Aziz

Comeon guys! Do your own proof to see, whether you get the same result (challenge offer).

In the mean time, I'll do an analysis for a ground loop coil configuration. This time, I won't publish the results and let this task to you all. I bet it would take another 20 years.

[ivconic]

And my favorite hobby is to print on paper such claims and theories and later to use that paper in such purposes!

Feeling is tough to describe!

[ivconic]

Hi Dave,

it's meant the coil current I (not the battery power of course). Don't we refer to the (TX) coil current, when we talk about 64x power requirement for doubling the detection distance? Anyway.

Well, I was believing the same (the 64x thing) until I made a true EM simulation using the numerical Biot-Savart simulation technique (via my own coil software). So it really depends on the case, when the power increase makes sense or not.
As you mentioned, there are many pitfalls using more power to the coil. But they can be solved to some degree of satisfaction.

What we can do easily today, is to increase the coil power by 2x or slighly more. Everything above 5x or even 10x is not practicaly. One need a very power efficient TX stage (>80% efficiency) to increase the coil current significantly.

The cheapest solution is still to reduce the EMI noise and rise the amplifier gain instead. Some coil arrangements like the anti-interference coils can gain a "power factor" of 10-20 times. That's a lot more instead of increasing the coil current actually.

To speak to the sceptics (who questioning my brave claim):
Everybody is invited to make their own (mathematical/physical) proof.

Cheers,
Aziz

Aziz, so far we hadn't see NONE of your practical solution, only plenty rhetorics.
This is mostly DIY forum (at least i understood it that way) and majority here are not very interested in ultra-high-turbo-mathematical-xyz*SQR/Pi-26(34/0,16)- brainstorming that you are very ready to present here from time to time.
This is real world and smart people should deal with real things mostly.
Instead teaching us how smart are you - you better give here something which is really your own, that you made it for real.
Something workable and usable...and of course provable and repeatable...
It is easy to make empty rhetoric and play with mathematic formulas, we others here can do that even much better without you.
Instead, give here something PRACTICAL and REAL.
Show us here at least ONE of your brainstorming works?
How about that?

P.S.
All rhetoric and theories that were didn't supported with physical work and physical devices so far - are good only for wiping ...you know what, when you go to toilet...