Delta Pulse

[Geo]

I like the box
Why at the first photo you use two bateries (they make the DP very heavy)
Regards

[nelson]

Hi all.
Yesterday i was playing with my DP coil, so i made a 28 cms coil, wire 04 mm, 22 turns, resistance 3.9 ohms. My results are the following:
1.7 cms copper coin, 35 cms, but DP sound a little unstable.
Then i played with few controls and got very nice stability, but also detection range got down to 28 to 29 cms.
A 1 cms aluminium coin, was detected at 22 cms, and after set the detector to the second set up, it was detected at 14 to 15 cms.
My dumping resistor is 2.2K, there was post before that a 1.2K works better.
Any ideas to get a good coil for coing hunting?

Regards
Nelson

What are you gonna do there ???
Today i wound 30 wind. on 20 cm , o.4mm wire...Well, i am not thrill with it
but it can detect 2cm coin on 28-29cm...almost done.What to say?
What ever result i get, always want some more..I keep thinking is it possible
to do 20cm coil to detect 2 cm coin over 35cm!? Only one detector i saw can
do that...Relic Hawk...coin is made from mixture of Cu and brass...Hard to test
with! O.K. when you try it please post results here.
Regards

[Geo]

Dirceu , Time to get out the Oscilliscope !! Check Q1 if its getting hot. Check your supply voltage and also your potentiometer connections and solder joints. With oscilloscope check where signal is missing or not enough gain . Your at the best part of the project , Getting it working !!! Do not give up , the Delta Pulse is a Good Machine ...Have a Great Day !! Eugene

Hi Eygene.
Waveforms are not OK.
If you will looking for, you will find my waves....
A big mistake is at delay1 and delay2 time.
Regards

[Geo]

Hi all.
Yesterday i was playing with my DP coil, so i made a 28 cms coil, wire 04 mm, 22 turns, resistance 3.9 ohms. My results are the following:
1.7 cms copper coin, 35 cms, but DP sound a little unstable.
Then i played with few controls and got very nice stability, but also detection range got down to 28 to 29 cms.
A 1 cms aluminium coin, was detected at 22 cms, and after set the detector to the second set up, it was detected at 14 to 15 cms.
My dumping resistor is 2.2K, there was post before that a 1.2K works better.
Any ideas to get a good coil for coing hunting?

Regards
Nelson

Hi Nelson. With DP is not so easy to detect a 1.7cm coin at 35 cm.
I detect a 20mm coin at 23...25 cm and a 25mm coin at 30cm max (with my DP).
DP is designed for big burried objects and at second reason for single coins
Regards

[nelson]

HI GEO. SORRY I PLASE WRONG DIMENSION OF MY COPPER COING. THIS COPPER COIN IS 2.6 CMS AND IS DETECTED AT 35 CMS.
REGARDS
NELSON

Hi Nelson. With DP is not so easy to detect a 1.7cm coin at 35 cm.
I detect a 20mm coin at 23...25 cm and a 25mm coin at 30cm max (with my DP).
DP is designed for big burried objects and at second reason for single coins
Regards

[1843]

Hi,
I just read the LF357 datasheet. It says that the maximum input voltage is 100mV higher than Vcc.
The max input voltage for LF357 is about 1V higher than Vcc in Deltapulse . How doesn't it get destroyed?

Regards,
1843

[Noemio]

pancake coil

Hi all,

I just finished to build this coil but it doesn't work good on my DP.
Very difficult to find an adequate value for dumping resistor, a lot of instability during work an a lot of ground effect.
It's 25 cm in diameter with 32 turns. It developes (only) 240 µH and 1,2 ohm.
Any comments or suggestions?

[A friend]

Hi all,

I just finished to build this coil but it doesn't work good on my DP....

Excelend work.
Did you try 2-3 om resistor in series with fet ?
Did you try up to ... 300 pulses ?

[Geo]

Hi all,

I just finished to build this coil but it doesn't work good on my DP.
Very difficult to find an adequate value for dumping resistor, a lot of instability during work an a lot of ground effect.
It's 25 cm in diameter with 32 turns. It developes (only) 240 µH and 1,2 ohm.
Any comments or suggestions?

Very good work.
DP needs more inductance and biger DC resistance.
As an example 700... 1000 uH amd 3....4 Ohm resistance at the coil connector.

[porkluvr]

Hi all,

I just finished to build this coil but it doesn't work good on my DP.
Very difficult to find an adequate value for dumping resistor, a lot of instability during work an a lot of ground effect.
It's 25 cm in diameter with 32 turns. It developes (only) 240 µH and 1,2 ohm.
Any comments or suggestions?

(Just curious) what gauge wire did you use?

I think your coil will have more capacitance towards the ground because your zig-zag wires add comparatively little inductance compared to the added wire length.

Additional parasitic parallel capacitance would cause the coil's decay curve to be relatively wide, compared to the decay curve of a coil with a more direct wire path.

[porkluvr]

... your zig-zag wires add comparatively little inductance compared to the added wire length.
.

What I was trying to say, is: your wires crossing at almost 90 degrees will have their individual magnetic fields partially cancel each other.

Apply the Left (-or right-) Hand Rule, to visualize. Where your fingers point at each other will be magnetic field cancellation.

[amtech2005]

Delta Pulse

GOOD MORNING PORKLUVR !! I AGREE 100% THE MAGNETIC FIELDS DO CANCEL OUT , BUT MY QUESTION IS DOES A NEGATIVE SIDE OF THE FIELD CHARGE A TARGET MORE THAN THE POSITIVE SIDE OF THE FIELD OR DOES IT HAVE TO DO WITH THE METALS AMOUNT OF FREE ELECTRONS IT CAN HANDLE??? HAS ANYONE THOUGHT OF THAT ?? . BUT THE MAIN REASON I REPLIED IS AT THE TOP RIGHT CORNER OF YOUR POST IT SAYS YOUR LOCATION IS 130 MILES SOUTH OF CARL !!!! I HAVE BEEN LAUGHING FOR OVER 30 MINUTES. THAT STATEMENT HAS ALOT OF HIDDEN HUMOR , I AM LAUGHING WITH YOU, NOT AT YOU. IF I LIVED THAT CLOSE TO CARL I WOULD POST THAT INFORMATION ALSO !!!. ANYWAY YOU ARE VERY LUCKY FOR MANY REASONS , A TECHNICAL GURU , SCIENTIST, LIVING SO CLOSE TO YOU... AND ALSO IF HE EVER HAD A GARAGE SALE OF HIS METAL DETECTOR'S ,YOU ARE RIGHT THERE AND DO NOT GET A SPEEDING TICKET !! . YOU HAVE A GREAT SUNDAY .....EUGENE

[porkluvr]

... IT SAYS YOUR LOCATION IS 130 MILES SOUTH OF CARL !!!! I HAVE BEEN LAUGHING FOR OVER 30 MINUTES. THAT STATEMENT HAS ALOT OF HIDDEN HUMOR , I AM LAUGHING WITH YOU, NOT AT YOU.

Well, you can laugh with me or laugh at me - whatever the case. If the shoe fits, I will wear it. I have made some dumb posts in the past and I will probably make more bonehead posts in the future. Sometimes I don't think- just open mouth, insert foot.

'Fer instance: just today realized that I have in the past erroneously extolled the virtue of using LT1012 in place of two LM308s, but, that's not a very good idea because the LT1012 is a single opamp. Yep, I did that.

But anyway, Noemio: look at BB Sailor's "Fast Coil" article, here:
http://geotech.thunting.com/pages/me...s/FastCoil.pdf
Also, Dave Emery's article: http://geotech.thunting.com/pages/me...planar_150.pdf

I live near some played out gold mines in Charlotte, NC. So, even though the Delta Pulse may be a good machine, I need a PI machine with faster response and receiver blanking - to find SMALL gold, if I'm lucky.

(I think that Dave Emery lives about 25 miles away, maybe I'll ask him if I can use his lab for set-up when I get up the nerve.)

Carry on Deltapulse!

[Unregistered]

good day to all. I am realizing the deltapulse. is possible to replace LF357 with LM318? Thanks for the answers
excuse my english

[aft_72005]

Hi
You can use LF356 instead of LF357 ,also I compared these two on delta pulse .
LF 356 had good result with lower S.R. against LF 357.