Lrl from Italy

[walkman]

Thank you very much for your guidance Mr. Franco.
It detects the lighter test very easily with a distance of 4m and a 20cm long antenna. I haven't been able to do a field test outside yet.

[electroaf]

good evening I am a new researcher in the LRL field I like your project I want to build this LRL but I want to know what is the resonance frequency of the system

[FrancoItaly]

My lrl is of the passive type as I think almost all the others are. The internal oscillator is only used to provide a reference signal, the reception frequency is determined by L1/C10 and is in the range of about 90/120Mhz. The most sensitive type is the one where L1/C10 is tuned to a harmonic of the quartz oscillator, the quartz frequency is 20Mhz but it is quite critical to realize. Of 3 20Mhz lrls made by me only one works well. I must warn that it is not easy to set up my lrl (even 8Mhz version) because of the very high gain it could easily self oscillate, if the gain is reduced too much it would be too insensitive, I recommend a single pcb for the sensor stage, of the double-sided type, with the lower face connected to ground and therefore with the components soldered on the upper part, without drilling the pcb.

[FrancoItaly]

My lrl was originally a self-oscillating rf sniffer that also worked as an lrl. Since it was critical to make, I added a quartz oscillator. For those making the 3-led version, I say to use the power supply stage of the 1-led version (in fact, it is not shown in the diagram). Power is provided by two 9V batteries in series.

[mc_307]

hello mr. franko. what happens if the value of the c10 capacitor is close to zero? can you give an example about changing the value of the c9 and c10 capacitors here? for example, what happens if the value of c9 is decreased? or what happens if it is increased. the same questions apply to c10. i wonder how the c9 and c10 capacitors affect each other. it is buried but i don't know what is inside, when the c10 capacitor is very low, i can only detect it when it is on it and from one direction. i want to increase this low value. does it make sense to change the value of the c9 capacitor for this?

[FrancoItaly]

Changing C9 is not needed, it serves to connect the filter to the TR2 base and its impedance to the frequency of the filter is very low, negligible. C10 determines the filter resonance frequency together with L1, put a variable capacitor (10/47pf) in place. If you do not put C10, however, the parasitic capacity of the basic/emitting junction of TR2 (about 7pf) remains.

[mc_307]

Hello Mr. Franko. I receive signals from 2 different places underground. One of them receives only in the west direction and slightly turned to the south. The other receives from almost 4 directions. However, it only detects when I come to it. There is no remote sensing. Do you have any advice regarding the remote sensing of the device? Which parts on the circuit are related to the remote sensing distance?

[FrancoItaly]

My lrl, like the others (except for modified metal detectors like Alonzo's pistol), works only as remote sensing and for metals buried for a long time. Anomalies in detection can depend on the type of soil, metal, burial time. We know little about the phenomenon that according to official science does not exist. The advice I can give is to do tests in the test field and try to understand how it works.

[abdou2014]

Hi Dear Franco , I hope you are well, I managed to find a lot of non-ferrous metals underground with your LRL, and I tried to increase the location distance by increasing the sensitivity, except that there is the effect of the sky and compass which is imposed,
Do you have a precise idea about the sky effect? What exactly is it ?

[FrancoItaly]

I can't give you an answer, we know very little about the phenomenon, regarding the compass effect the Earth's magnetic field is undoubtedly important and for the sky the effect could be due to the electrostatic potential which increases as the height from the ground increases.

[abdou2014]

I ADDED 50Hz NOTCH WITHOUT SUCCESS TO AVOID SKY EFFECT WHY ?

[FrancoItaly]

Why put a 50Hz filter when this signal is not there? If you use the lrl in a place where there are high voltage power lines it does not work.

[aft_72005]

My lrl, like the others (except for modified metal detectors like Alonzo's pistol), works only as remote sensing and for metals buried for a long time. Anomalies in detection can depend on the type of soil, metal, burial time. We know little about the phenomenon that according to official science does not exist. The advice I can give is to do tests in the test field and try to understand how it works.

Hello Franco.
Years ago... when you built remote sensing based on a separate transmitter and receiver... I corresponded with you privately... after studying your new circuit... its performance is clear. And how it detects the target...many people do not know the philosophy of revealing the phenomenon and I think it is better to keep it secret.

[FrancoItaly]

I don't remember exactly what you're referring to, but in my opinion even if there is a transmitter it still works as a passive receiver and not as a radar, in fact if that were the case the transmitted signal should reach the buried metal and then come back.

[aft_72005]

I don't remember exactly what you're referring to, but in my opinion even if there is a transmitter it still works as a passive receiver and not as a radar, in fact if that were the case the transmitted signal should reach the buried metal and then come back.

Well, many people think that it has a radar function.. and The return signal is in the FM band.. Do you know about this?