Lrl from Italy

[zixelll]

Thanks for giving me the complete final file for making this circuit

[FrancoItaly]

This answer is for maziio, that sent me a private message but I can not answer him:

I have simulated with multisim and the sensor stage works with BC183C or BC183B or equivalent but obviously it is not possible to simulate it completely. Essentially the sensor stage is composed of a high gain amplifier (TR2-TR3-TR4) that amplifies a small part of the signal coming from the 8Mhz oscillator and that is what can be simulated. The "heart" of the lrl is centered on TR2, where the mixing between the 8Mhz signal and the signal coming from the antenna takes place. The main difficulty is to prevent the whole sensor stage from becoming an oscillator and at the same time having a good amplification. On the forum there are some PCBs posted by members that include the whole lrl. In my opinion it is better a separate PCB for the sensor stage, better if double-sided and this is what I did.

Best Regards

[zixelll]

Hi Franco, my device when I'm buried on the target goes on a beep and its sound is not interrupted, but I'm testing it at home. Turning off the device, the sound is cut off because of what it is.

[abdou2014]

SENSOR

[abdou2014]

OK

[abdou2014]

The long capacitors are resistors , to reduce the size of PCB !

[FrancoItaly]

Hi Franco, my device when I'm buried on the target goes on a beep and its sound is not interrupted, but I'm testing it at home. Turning off the device, the sound is cut off because of what it is.

I don't understand what you mean, at home it's not possible to test the lrl, it's possible also in open field with buried metal (after 1 month or more).

[zixelll]

Franco What is the best volume for this device?

[zixelll]

Military or ordinary

[FrancoItaly]

Franco What is the best volume for this device?

for volume do you mean "box" ? It's not important, plastic or metallic it's ok, but the handle is better metallic or shielded with aluminium foil.

[zixelll]

I mean the volume

[zixelll]

Is the military volume good? Does it matter?

[zixelll]

Hello Franco, what's my best transistor for this device and what is the best beta?

[FrancoItaly]

Hello Franco, what's my best transistor for this device and what is the best beta?

I use BC183C but every BC...C or BC...B are good. Beta more than 500

[zixelll]

What is beta more than 500?