How to improve my Surf PI 1.2 for a mission like this: Underwater search for iron/steel solely

[kt315]

ok. still pics from winter amigo!

[kt315]

[Qiaozhi]

As for pulse delay and TX width, I will try those numbers. But at this moment my lack of knowledge on how to adjust TX width on the Surf PI 1.2 keeps me from trying that.

U1 (555) is the TX oscillator. You could change R1 (100k) to 180k, and R2 (3k3) to 22k. This will give you a TX pulse width of 332us and a transmit rate of 329pps. Alternatively, replace R1 and R2 with trimmers, and adjust the values to get exactly what you want. However, the Surf-PI also uses the TX oscillator to generate the audio tone, which is 623Hz, so the audio tone will be much lower if you change these components.

I don't know the maximum sample delay setting on the Surf-PI, but this is adjusted by P2 (100k). You may have to change the values of P2 and/or C9 to achieve 100us.

Otherwise, have a look at Minipulse Plus Rev-E, which already has on-board trimmers to allow independent adjustment of the PX pulse width and transmit rate. There is a separate VCO audio oscillator, which means that the audio tone will be unaffected.

[Loola]

mine coil 1mx1m was esp-ly projected for seach in winter time and in summer time on boat drilling (you know this small resine fishers pumping boats).
write if you need more winter pics.

Kt315

Thank you for the book tip! I will look it up.

Aha, was you walking on ice and searching on the bottom?
If so, what was the maximal depth of water that you were able to get signals?
I live in the northern part of Sweden and we have frozen lakes and rivers at winter.
So it would be a good option on searching at bottoms. Interesting certainly. If my assumptions are right there is.

[Loola]

U1 (555) is the TX oscillator. You could change R1 (100k) to 180k, and R2 (3k3) to 22k. This will give you a TX pulse width of 332us and a transmit rate of 329pps. Alternatively, replace R1 and R2 with trimmers, and adjust the values to get exactly what you want. However, the Surf-PI also uses the TX oscillator to generate the audio tone, which is 623Hz, so the audio tone will be much lower if you change these components.

I don't know the maximum sample delay setting on the Surf-PI, but this is adjusted by P2 (100k). You may have to change the values of P2 and/or C9 to achieve 100us.

Otherwise, have a look at Minipulse Plus Rev-E, which already has on-board trimmers to allow independent adjustment of the PX pulse width and transmit rate. There is a separate VCO audio oscillator, which means that the audio tone will be unaffected.

Qiaozhi
This was valuable info for this project. Many thanks.

[Loola]

I have the search coil in another town so at this moment I cannot test this settings that you guys so nicely have shared, but soon I will be able to do some testing.

Another question that rises: Is it possible to do searches at the bottom of lakes in the winter, and do so by walking on the ice. With let us say a deep seeking PI. Or would it just penetrate the ice and one or two meters more (depending on how good your detector is). I.E how would it function with a deep seeker on a frozen lake? What depth could one expect to reach?

[kt315]

you do not see main problem. no difficulty to seek a something on 3-4 meter of depth, but how you will lift it up?
all heavy metal were left on a bottom because no instrument to hook up it and lift.

[Ferric Toes]

you do not see main problem. no difficulty to seek a something on 3-4 meter of depth, but how you will lift it up?
all heavy metal were left on a bottom because no instrument to hook up it and lift.

Air bags have been used to lift large cannons. Lift them off the bottom then tow to shallow water or a ramp. Same for any heavy object. Obviously you need to dive to attach straps or cables to the object, plus an air compressor. Do the survey on the ice; take GPS co-ordinates; then go back with the airbags when the ice has melted. Best to see what you have found before lifting though.

Eric.

[Ferric Toes]

Is this real, or a fake? I see my name is on the cover, but it is NOT with my courtesy at all. I fully recommend the real book which is solely the work of George Overton and Carl Moreland. Explanation Please!

Eric.

[Qiaozhi]

Is this real, or a fake? I see my name is on the cover, but it is NOT with my courtesy at all. I fully recommend the real book which is solely the work of George Overton and Carl Moreland. Explanation Please!

Eric.

It's a fake.
Just one of KT315's little jokes.

[qute1]

It is also a good advert for you as both KT315 myself and many others feel that the answers to near everything MD related reside in this very tome.

[kt315]

maybe. it's Third Edition. yet did not released. in stage of run-up.

[qute1]

[kt315]

Air bags have been used to lift large cannons. Lift them off the bottom then tow to shallow water or a ramp. Same for any heavy object. Obviously you need to dive to attach straps or cables to the object, plus an air compressor. Do the survey on the ice; take GPS co-ordinates; then go back with the airbags when the ice has melted. Best to see what you have found before lifting though.

Eric.

thank you Eric. nice way.

[kt315]

from bottom