Hypodermic needles

[Nupi]

Very convincing wet sand and ferro part discrimination and still hypo-needle detection. Did you use salt water?

Yes, 100% North Sea water, salt water from Holland. It does not smell very good.
In my hobby room I have a plastic box stand for testing to.
The layer thickness of the sand is 10 cm.
It is the same beach sand that I have used in video to test the PP.

[Nupi]

Thanks.

Hi 6666,
what do you mean by private project?

[6666]

Hi Nupi I was asking Qiaozhi
about his prototype PI bipolar transmitter .

[Nupi]

Hi Nupi I was asking Qiaozhi
about his prototype PI bipolar transmitter .

I see it now, Sorry.

[green]

Made a DD coil, each half 3/8 x 9/8 rectangle. Couldn't see a change on the coil off decay like I did with the mono coil for the hypodermic needle. Saw something I didn't expect during the coil on time. Including scope traces of amplifier out with no target, 5 x 5 mm aluminum foil and a hypodermic needle.

[green]

[QUOTE=green;195181]Made a DD coil, each half 3/8 x 9/8 rectangle. Couldn't see a change on the coil off decay like I did with the mono coil for the hypodermic needle. Saw something I didn't expect during the coil on time. Including scope traces of amplifier out with no target, 5 x 5 mm aluminum foil and a hypodermic needle.[/QUOT

It's been awhile and I forgot the aluminum was cut from a can and not foil.

[Nupi]

Made a DD coil, each half 3/8 x 9/8 rectangle. Couldn't see a change on the coil off decay like I did with the mono coil for the hypodermic needle. Saw something I didn't expect during the coil on time. Including scope traces of amplifier out with no target, 5 x 5 mm aluminum foil and a hypodermic needle.

Hi green,
I assume you have received the hypodermic needles?
Which of the three needles that I sent you, did you use?

[WM6]

[QUOTE=green;195182]

Made a DD coil, each half 3/8 x 9/8 rectangle. Couldn't see a change on the coil off decay like I did with the mono coil for the hypodermic needle. Saw something I didn't expect during the coil on time. Including scope traces of amplifier out with no target, 5 x 5 mm aluminum foil and a hypodermic needle.[/QUOT

It's been awhile and I forgot the aluminum was cut from a can and not foil.

Interesting and promising observation green. Was needle during test in your hand or sticked at something like plastic ruler?

[green]

Hi green,
I assume you have received the hypodermic needles?
Which of the three needles that I sent you, did you use?

I haven't received them yet. It's the same needle I was using.

[green]

[QUOTE=WM6;195186]

Interesting and promising observation green. Was needle during test in your hand or sticked at something like plastic ruler?

The needle was laying on the coil. Same signal with less amplitude when farther away

[Nupi]

I haven't received them yet. It's the same needle I was using.

Strange that you have not yet received. I've posted the June 22
it takes an average of six days, they said at the post office.

[green]

Strange that you have not yet received. I've posted the June 22
it takes an average of six days, they said at the post office.

Thanks for sending them. I checked the address I gave you to see If it was correct. It was, maybe slow mail.

[green]

Was comparing some other targets with the hypodermic needle I have. PI amplifier out during coil on time with an IB coil. Some clay from the back yard and a couple different ferrite beads look close if not the same. When Nupi's needles arrive I will do a better comparison. Does anyone have an idea why the hypodermic needle would cause a signal similar to ferrite? Maybe Nupi's needles will be different.

[green]

Got a needle. Target signal during coil on time, not off time. Lower response than ferrite at end of coil on time. On the bench with a small DD coil, Don't know if I could get a detector to detect it on the ground.

[green]

Got a needle. Target signal during coil on time, not off time. Lower response than ferrite at end of coil on time. On the bench with a small DD coil, Don't know if I could get a detector to detect it on the ground.

I think the statement about the ferrite is wrong. I had just recorded the ferrite on a different coil for another thread and the signal didn't decay to zero. Tried some things this morning. If I unbalance the coil so that the trace looks like the needle trace I can make the trace look like the no target trace with the needle, 2 blade safety razor, ferrite core and some clay from the yard. No visual indication at turn off with either target. The ferrite and razor don't need to be as close to the coil to balance it. All the other targets I tried wouldn't balance the coil.