Compass Depth Doubler

[ivconic]

[ivconic]

Does anyone have any information about the voltage at the electrodes? Thank you.

...At bench experiments with 15 ohms / 20W it draws 0.78A. In soil it is variable, depending on soil...

Although I shouldn't; I will disclose only this one too.
At given bench tests the amplitude of the very special waveform is ~65Vpp.

[Skippy]

A few comments:
Ten probes spaced 1.2m apart means the total length is 9 x 1.2 = 10.8m , not 12m.
I think if the probe lines were staggered by 0.6m ( half of the probe seperation ), the device may have a more even effect of the ground and targets.
I would connect the electronics box to the 'blue' probes with a short ( 30cm ) wire, and run a 3m wire to the end of the 'yellow' probes. If a spacing greater than 3m is used, add a single 3m extension cable into the 'blue' probe line.
What do you think the best cable to use would be ? I was thinking flexible test-lead wire, like that on a DMM. High current rating is not needed, so the thinner stuff would be fine.
The electronics box could be built with two 'yellow' sockets and two 'blue' sockets. And the probe set is split into two sections, such as [ 2 x 5 plus 2 x 5] or [2 x 6 plus 2 x 4 ] , which would give you the option of running smaller installations if needed.
Do you think a 3-row set-up would work ? I think three rows of 5 probes would be electrically like two rows of 10 probes. The middle row connects to the 'yellow' output, the outer two rows connect to the 'blue' output. That would cover the same surface area, but needs only 15 probes, not 20.

[ivconic]

Your math is bad.
You don't want the device to be between the two probes or near the signal path, but slightly outside the "rectangle".
You get a larger area to search. A longer cable is not a problem. That's why I left 10x1.2m = 12m.
Otherwise, the length of the cable is not important, in my case I will use 2 cables of 15 meters each.
I chose a cable with silicone insulation and very rich fat litz. It is a conductor made of ~30 twisted strands.
I think that the original purpose of that cable is to connect strong sound systems with a power of 500W and more.
That cable is otherwise very strong and about 5-6mm thick with insulation. Very elastic, suitable for frequent manipulations.
That's why the cable has a very low resistance, I didn't measure it, but I know from before. 0.2-0.3 ohms for the 20 meter cable.
So a few meters more or less; does not bother.
The whole setup is quite tentative because it is the soil properties that will cause frequent changes in that configuration of probes with cables.

[Artyom]

Thank you for the clarification. If I understand correctly, you need to search while the device is running? How does this affect the operation of the metal detector?

[ivconic]

..I think if the probe lines were staggered by 0.6m ( half of the probe seperation ), the device may have a more even effect of the ground and targets...

And I think that's true.
But there is no need to change the length of the cable in that case.
The probes remain on the cable according to my sketch from the previous post,
you only gather the probes to a smaller distance and throw the "excess" cable between them outside the "rectangle".
Because in this way with one and the same cable and "clips" for tests, which are soldered to the cable;
you can reduce the maximum area (12x6m) to smaller areas if you wish.

[ivconic]

Thank you for the clarification. If I understand correctly, you need to search while the device is running? How does this affect the operation of the metal detector?

You can work with the detector even when the Depth Doubler is on, but you can also turn it off while working.
In the first case, the effect on the targets does not decrease but remains the same, in the second case, the effect on the targets slowly decreases and is lost, with the passage of time.
A good question is how the detectors will behave.
How which.
Different.
Deus is "naturally" quite "nervous" when set to "hot" settings (best depth performance).
Well, it constantly "squeaks" anyway when adjusted to "hot".
With Depth Doubler on; Deus continues to "squeak" a little harder.
But those "squeaks" still does not cover up and interfere with clear responses to real targets.
TGSL for example, is a very "calm" and "silent" detector.
It remains so even with the Depth Doubler. Etc.
Depends on the detector... depending on the "temperament" of the detector!

[Skippy]

"Ten probes spaced 1.2m apart means the total length is 9 x 1.2 = 10.8m , not 12m"

"Your math is bad"

So you think the effect of the end probes will extend 0.6m beyond the end of the rectangle, increasing the area covered back to (10.8 + 0.6 +0.6 )m by 3m? Seems reasonable.

[ivconic]

"Ten probes spaced 1.2m apart means the total length is 9 x 1.2 = 10.8m , not 12m"

"Your math is bad"

So you think the effect of the end probes will extend 0.6m beyond the end of the rectangle, increasing the area covered back to (10.8 + 0.6 +0.6 )m by 3m? Seems reasonable.

Generally yes.
But individual conditions in the soil will significantly affect the width of the signal spread from probe to probe.

[ivconic]

How to accurately drill holes on such bars?
And that the holes are regular and always in the same place on the rod?
There are many ways in professional machining.
From the lathe as the most precise... all the way to the ordinary column/pole drill.
A lathe is an expensive toy to have in a modest electronics workshop.
Column drill... so... there are ads with prices as low as 60e.
Made in China.
I had the opportunity to see them at an acquaintance's house.
They are of no use. They have a "gap", they are not precise, they are wobbly, very badly done... although visually they look very good.
But who has tried to do some work; he realized how badly it was done.
I assume that there are also very high-quality column/pole drills, but the prices are probably very high.
If only a man could have everything he needs!
And how can I now drill 20 bars and have all the holes be regular and in the same place?
Very easy actually!





"Template" for drilling.
The metal accessory, the tube, is from a radio FM telescope antenna.
Such antennas are made of several segments, each with a slightly larger diameter.
So it's easy to choose a part that will be slightly wider than the diameter of the drill bit.
It is glued into the plastic part with epoxy.
And serves as a "guide".

[Gwil]

According to post #16, Compass offered a money back guarantee. Maybe this is why they had to stop making it.

Or maybe I'm being too suspicious.

[ivconic]

According to post #16, Compass offered a money back guarantee. Maybe this is why they had to stop making it.

Or maybe I'm being too suspicious.

Suspicious of what? I'm not sure I understand what the point is?
It was a common business practice (a very good one) in those ancient times.
Most manufacturers of metal detectors have guaranteed money back to customers, if for some reason they are not satisfied with the product.
And that's good practice.
It speaks about the reputation of the manufacturer, but also about the quality of the product.
The last "Mohicans" have long since disappeared, today it is no longer a practice, so it seems strange when you see something like that.
The company Compass produced very good products.
Why did they disappear?
Probably due to the sudden appearance of many younger companies, due to competition, etc.
There can be many reasons.
We'll probably never know.
Unless someone who was a direct contemporary and participant, and knows the details, comes forward.
Why did White's disappear?
Tesoro?
Some other?
And we know that they produced good and quality products.
The laws of the market are inexorable and the emergence of new players brings fiercer competition.
And the recent appearance of eastern hyperproduction further increases the pressure on all that.
We can ask why this... why that... I leave those questions for those who have nothing better to do in life.
I have lot of better things to do in my life, so I won't waste my time on such things.
Depth Doubler is the first on such my list of better things to do in life.

[Skippy]

Since the "ten day bid period" seems to have expired, may I ask if Mr Ivconic has had sufficient enquiries about his boards ?

[Gwil]

My suspicion was that many people found that the Depth Doubler didn't work, at least not for them, and Compass had to part with a large amount of money.

I expect I'm wrong though. Like I said, too suspicious.

I look forward to reading reports of the success people have using this system.

[ivconic]

Since the "ten day bid period" seems to have expired, may I ask if Mr Ivconic has had sufficient enquiries about his boards ?

No, I don't sell boards (pcbs), you missunderstood it.
I put on "auction" project; schematic, pcb, all the other info (sch and pcb are not enough to make it alright).
Low interest, only 2 bids on email, both are kinda jokes.
So, as things go on; this will remain undisclosed.