lobo improved

[tchoci]

Hi Foma.

[FOMA]

Hi Tchoci.

Please do;make photo of the detector LOBO.
Folk distrusts.

[tchoci]

Izvinyavaite for bad English, but I am from Bulgaria and not know it very well.

[tchoci]

In my case, a R7 = 1,25 kom.Probvah a higher value but started to do curves and land.

[tchoci]

Do not forget that the efforts of a host depends on the amplifier OOV for each school should be carefully selected resistors OOV.V case of U4.

[maxbiri]

Hi Tchoci

I found on my board that rx phase must be a little positive respect tx signal for best ground balancing and disc, may be +20,+30°.
What about yuors circuit?
32 cm look very good! on my board i detect a 50 eurocent no more 25 cm in air.

Bye Max

[tchoci]

I try very schemes, Lobo was the last before TGS, but I like and the sound of real life into LOBO, discriminate cool and contaminated land, land with no problems, also holds temperature dobre.Dalbochinata also good.

[tchoci]

Hi FOMA,
I have several adjustments that you forgot to write; R7-1.25kom; R49-200kom; R51-100kom; R53-82kom

[tchoci]

U6-lm392

[FOMA]

HI TCHOCI

Last question - what microcircuit U6?

[tchoci]

thank you for the scheme and developed platka.Imashe error SW1A just have to pass the lower conclusion above does not work correctly because of the general regime.

[tchoci]

maximum resonance of Rx is given by 3,3 nf but no land.

A perfect sine of Tx is obtained by 2t914a and Ctx 44nf, total consumption of the appliance without sound is 71mA

[tchoci]

Hi Foma,
The coil is DD ,
Crx-1,3nf the best GROUND in real conditions
8nF don't have good GROUND
i tested this on the field

[FOMA]

HI THCOCI.
How much mA it is necessary for scheme
What microcircuit U6?
Strange that capacitor Crx = 1,3 nF, he must capacity =* 8 nF.

[porkluvr]

LOBO the best. 50 €cent -32sm. for air.Discriminate-OK,F=17kHz,Vpp/gen.-14v.Ground-OK
Q1-2T914A;U1-HA17555;U4,U7-NE5532;U10,U11-OP177;Ctx-44nf;Crx-1,3nf;U8,U9,U14-LM158;U13-TL072

Congratulations tchoci! Sounds like you have a winner. From your data it is easy to approximately calculate your transmit coil's inductance by using resonance formula, but your receive coil will remain unknown because that is not a tuned circuit. Do you have means to measure RX coil inductance? Please tell if you can.

Hi,FOMA
coil-Tx=65/0,28 Rx=170/0,22 D=22sm.

Update: You have posted your coil dimensions and winding numbers so I think I could use a coil calculator to determine RX coil inductance.

Why is there only one number for coil dimension? If this is a DD coil we actually need LxW for more complete detail. Or maybe it is OO coil? What coil configuration did you make?

22sm (or 22cm?) is about 8.66 inches... I'll figure this out... gotta' go now, bye.

Wait, one more question: Should I assume the 0,28 and 0,22 wire width numbers refer to bare wire? (Of course, stupid question. Right?)