help for 1x1 mt. coil for Vandal pulse 2

[lamaison33]

hello,

I would like to buy a Vandal pulse 2, but I need help with the construction of the coil 1x1 m.
can you explain step-by-step the construction and the material needed?

thanks for your help
Simone
P.S.




I have very little experience in electronics!

[Funfinder]

You buy a roll with 200meter of enamailed copper wire 0,3-0,5mm diameter and some meters of tape
and some 3cm thick plastic tubes (pipes) incl. angles and connection pieces and 2 large no metal containing holding belts.

Put 4 plugs of wood into the soil in a square shape of 1m, wind the wire around it (49 x 4m) leave 2m for the connection with the detector free.

Tape the wire tight together.
Stick the tubes together and fix the wire on the upper side of the 1x1m plastic-pipe-square.


1m PI coils is such a simple crap. Don't expect too high performance.
The better the frame where the wire is fixed and how good the wire is attached the better for you.

If you have too much time you also can try to get the coil into the pipes, by opening a small space over the whole 4meters.

Have fun.

[lamaison33]

thanks for the explanation, not necessary to shield the cable? which wire should I use to connect to the metal detector?
why you have said that don't expect too high performance?
regards

[lamaison33]

up

[kt315]

up for what?

[kt315]

....

[Funfinder]

Hi and how is your progress? I hope good and you have started already to built something.

Shielding the cable only makes sense to shortcut electrostatic potentials or if the ground-balance circuit needs it.
PI pumps a whole inductions-flood into the soil and waits for the feedback more or less micro seconds later so the shield would just hinder that.
Of course there are differences how much EM-energy the shielding material can catch but however -
Logically seen shielding a coil is the same stupid than shielding an antenna from all sites.
In extreme cases the shielding can shortcut the whole inductivity field and render the coil useless.



> why you have said that don't expect too high performance?

Its good that you are interested in this topic:


1. 1m coils won't detect smaller stuff (5cm and below), especially if moved 30cm above the ground

2. the usual "walk inside the coil" method reduces the sensitivity

3. for higher inductivity you should use at least 200 windings and not only 50. Perhaps you should try it, using 0,15-0,25 mm thin enamailed wire.
But it depends one the pulse strenght - a higher inductive coil needs more amount of time to built up the EM-field.
Depending on the Pulse time and how fast the feedback circuit reacts the PI detector may not be able to work with such high inductive coils.
But you can try it and if you are lucky you may achieve ca. 50% more depth.

4. 1m coils need some stability and such plastic pipes while walking with the coil may shift and distort the field of the coil.
You could stabilize them however until just enough place for walking remains inside or you can mount some plastic wheels for draging the coil behind you.

5. 1m PI coils need some experience because of their huge interference potential you could get false signals if the ground below changes or contains hotrocks.

6. Because 1m induction balance coils are much better and stable. They also have much better discrimination ability compared to those PI discrimination "tricks".
But so far besides some turkish detectors like Jeohunter or DeepHunter there are only very few detectors with real large induction balance coils.

7. For maximum performance you would need the exact PI-electronic-system values to create a coil that works best with the detector.
Those 1meter DIY coils are working - perhaps on a 60-80% level compared with the max, but better you ask the creator of the PI for the perfect coil values
if this info is available and if you wanna get the best results. And if the stuff you are searching for is larger than 50cm in diameter and very deep better
create directly a 1,5m coil.


Have fun.

[lamaison33]

Hi Funfinder,
I ordered the device, and I'm going to adapt my 1x1 mt. frame coil of the Lorenz deepmax X6, it is a professional coil with shielding system,I hope it can be possible.
Best regards

[bernte_one]

best method
use a signal cable (telephone cable) 12*0,6mm or 10*0,5-0,6mm
connect single core wires in serie
ready

500-700µH is ok
resistance measured at the end of the connector cable not much bigger than 3R

kind regards

[lamaison33]

Thanks for everything Bernte,

[Funfinder]

Hello lamaison33,

let's hope it works and you found already enough info about the both coil-values so you can expect the difference will be not too critical.
For best results you really should buy some meters of wire and try how many windings and perhaps even what diameter will create
the best performance for what objects you're searching for.
That way you also will hear how good is the feedback-timing (signal output) depending on the amount of windings, how sensitive is the receiving circuit and
what size works optimal for your purposes.

Have fun.

[lamaison33]

thanks Funfinder, I'll probably have to experiment to find the best adjustment.