Delta Pulse

[mushaba]

The resistance of the coil is correct.
I built a similar coil and the resistance and inductance values are similar too.
Experiment, with the damping resistance to get the correct value, and it should work fine.
Adjust frecuncia for better stability.
If it is necessary to improve the stability, try a series resistance of 1 ohms 5 watts with the coil.
When it achieves optimal performance,try eliminate the series resistance.

Hello Jose!
Just tested indoors the square coil,i have it supported on a wooden pallete because my other coil carriage isnt glued completely.
It damps near 128 Ohms,strange thing my other monocoil for delta i built (50cm OD 0,55mm double enameled coil wire 375uH 2 Ohms) damped with same resistor value,is that normal??
The damping precedure i make with 3 different pot-resistor sets..

It seems to work great but it "hits" many ferrous targets as my workshop is mainly constructed with steel.

[Jose]

The resistance of the coil is correct.
I built a similar coil and the resistance and inductance values are similar too.
Experiment, with the damping resistance to get the correct value, and it should work fine.
Adjust frecuncia for better stability.
If it is necessary to improve the stability, try a series resistance of 1 ohms 5 watts with the coil.
When it achieves optimal performance,try eliminate the series resistance.

[mushaba]

Tried a 1 x 1 with 1.0mm multistrand wire PVC insulated,10 turns gave 370uH and 1.1 Ohm resistance,should the resistance be that low?

[mushaba]

what type of coil you want? demountable or undemountable?

Probaply demountable because i will have to dismantle it so it can travel...I made as the photo below 4 pieces that a square wood is glued to one wooden broom stick.Then it can be assembled and locked with pastic pins.I think it would be ridgid..

My question is what kind of wire (single core or multistrand) 1mm?1,5mm? And how many turns.

[kt315]

what type of coil you want? demountable or undemountable?

[mushaba]

OK my bad!

Any advice for 1m X1m coil??

[kt315]

just notice. change first pot marking on front panel from SAMPLE PULSE WIDTH on PULSE WIDTH. in the schematic SAMPLES' WIDTH is constant, untuneable, and length approx 45us.

[mushaba]

Hello!

Almost finished my DP Legend+ build,must admit it's a very strong detector!!!Planning to use it with 1m X 1m square coil but i've made also a 50cm OD mono coil from 0,55mm double enameled coil wire.

At first i attached a 40cm monocoil i had allready made,noticed 2 things: 1) it dumped pretty low 280 Ohms and 2) When i tried to increase main sample width the low batt led came on,the detector seems to need more power to drain so i put single core 2mm wires to power supply and added 2 X 10.000uF/63V to help it.

As for my 1x1 construction im a little confused about wire diammeter,found a pic from Sniffer XR71p brochure that uses 1.5mm wire (i guess PVC multistrand) 16 turns..Also found another document from another 1x1 that uses 0.66mm coil wire (enameled) 10 turns..What is the best option here?I have 1mm multistranded PVC insulated and 1mm solid core PVC insulated??

My build so far,KT i hope for your help and as you advised made electrostatic insulation on housing,first with coper lines soldered together and then sprayed with conductive graphite spray.

[kt315]

I never saw this configuration of the CD4538 as monostable and the outputs marked with TR4 and TR5 I observe a square wave of 3uS
Carlos

you was absolutely RIGH Carlos. i only just see now that CD4358 does NOT working in this configuration. i also see those 3us pulses.
must change BOM file.

use HEF4538BP, 74HC4538N, MC14538BCP

[kt315]

datasheet of RCA is OK. nothing of specific or different. i think i have to split RC circuit in two and look a result.
a structure of the chips may be different but we can not see that.

[dbanner]

Have a look at the RCA data sheet, maybe there is something little different.

[dbanner]

OK, now I understand. I am using NTE4538B in my Delta. VD5,VD6 normal 4148 I have used. T4,T5 very clean and stable, both pulse width are the same for me.
Delta is very nice circuit, capable of many possible modifications.

[kt315]

Time base is switched on scope?. T4 width unchanged.

the changing is going so fast that camera can not transfer it. see THE LINE UNDER SIGNAL and you will get no GAP there.

[kt315]

i noticed strange effect. CD4538 (RCA) is working stochastically. T4 and T5 width changed.
i think general circuit VD5 VD6 R8 C5 for them inapplicable. also, i looked XR71 schematic and VD5 VD6 are Schottky there, BAT85.
also effect that T4 and T5 have different width although have to be equal. not so critical although.

[dbanner]

Time base is switched on scope?. T4 width unchanged.