Protek Gtx 711

[GOLDEN LILLY]

Hello Guys, I just want to know if anybody had the schematics of Protek gtx 711 lrl. There is an existing thread on this one but none of them gives the correct details. All i know is that this lrl is like a two box MD but long range in category. I build it based on the schematics found somewhere in this forum but not sure if the schematic i got is the same principle used in the original protek. All i know is that the original used a colppits oscillator for its transmitter and i don't know if the tx is modulated... Any help is highly appreciated...

[GOLDEN LILLY]

This is my project. I used a 534 khz ceramic oscillator instead of 800 khz as the latter is very difficult to find. Also, the receiver has difficulty of receiving the transmitter signal unless the receiving coil is positioned near to the tx coil. I think the Rx needs more pre-amp. Please i need assistance...

[Geo]

Prototype has very sensitive receiver.
Maybe schematic has errors or it is not complete.

[GOLDEN LILLY]

Please explain to me how is this thing works...

[Geo]

I don't know.
I am not the inventor of it :frown:

[Pahom]

Good night !!!! Radio engineers, explain the scheme of the transmitter. I understand correctly that the LM 741 acts as a carrier generator ???

[abdou2014]

This is my project. I used a 534 khz ceramic oscillator instead of 800 khz as the latter is very difficult to find. Also, the receiver has difficulty of receiving the transmitter signal unless the receiving coil is positioned near to the tx coil. I think the Rx needs more pre-amp. Please i need assistance...

THE RECEIVER IS LIKE THE ARDF DIRECTIONAL ANTENNA

[Pahom]

THE RECEIVER IS LIKE THE ARDF DIRECTIONAL ANTENNA

In the photo, the receiver, to search for transmitters. Fox Hunt!

[humhum]

Please explain to me how is this thing works...

Tx all time send Wave , also time Rx receiver one parts from this wave , wneh is so , You will fine Calibrated and reset noll your Receiver and search around place for anomaly .

[Geo]

Good night !!!! Radio engineers, explain the scheme of the transmitter. I understand correctly that the LM 741 acts as a carrier generator ???

It is AGC amplifier.
Output of transmitter must be very stable!!!

[Pahom]

Thanks Geo !!!! So it’s like a generator and so on quartz. It is not clear that the AGC amplifier. There is a full name or purpose of such an amplifier.

[Geo]

Thanks Geo !!!! So it?s like a generator and so on quartz. It is not clear that the AGC amplifier. There is a full name or purpose of such an amplifier.

It is clear agc ampl.
At some models there was a resistor parallel to C24(feedback).

[Pahom]

Nevertheless, a tunable carrier frequency generator was assembled on the LM741. So far I figured it out. Thank you I will further study the operation of this device.

[Geo]

Many years ago (15++) i met the inventor of this detector.
He told me how it works and i constructed one...
Also i have opened 3 of them at my lab.
It is a very dificult to adjust detector and also it is very heavy and sensitive to human that operate it.

[Pahom]

I understand you. maybe ...... maybe I'm wrong. But that I will be mistaken. You went through all this. For years and costs. With your results. HAPPY NEW 2020 !!! !!!!! All treasure seekers !!!!

[Jeg]

This is my project. I used a 534 khz ceramic oscillator instead of 800 khz as the latter is very difficult to find. Also, the receiver has difficulty of receiving the transmitter signal unless the receiving coil is positioned near to the tx coil. I think the Rx needs more pre-amp. Please i need assistance...


Hi Golden
Nice building skills!

What is your final conclusion for this circuit? Does it worth for building it?

[Geo]

These days i had one at my hands...... and measured the Tx frequency, it was 125Khz.

[Jeg]

These days i had one at my hands...... and measured the Tx frequency, it was 125Khz.

Thank you George! Really? That low?
So we are not talking about emission in the sense of radio waves. Does the device trace the phase shift between emitter and receiver??!!

[Geo]

Phase shift !!!.. no, i don't think.
Maybe a 2box for big objects and why not a receiver for phenomenon.

[Jeg]

Great Geo! Thanks for the info. Is there any possibility that 125Khz is a modulation frequency riding a carrier at Mhz? Length of antennas normally suggest a carrier at tenths of Mhz!!

[Geo]

Jeg, no modulation signal. The Carrier is at 125Khz.

Regards

[Jeg]

Thanks Geo:)
Then i wonder if the advertised distance is true!

[Geo]

Who is the advertised distance?

[Jeg]

Who is the advertised distance?


"ΟΔΗΓΙΕΣ ΧΡΗΣΗΣ
Ο χειριστής λειτουργεί το protek περιστρέφοντας το σ? ένα πλήρη κύκλο 360 μοιρών και λαμβάνει ένα διακριτικό ήχο και εμφανή ένδειξη διαπήδησης της βελόνας οργάνου όταν βρεθεί στην ευθεία με το σημείο της ανωμαλίας πεδίου , επίσης με τη μέθοδο του τριγωνισμού , μπορεί να βρει το σημείο της ανωμαλίας πεδίου .
Απόσταση ανίχνευσης : περίπου 330 μέτρα":lol:


Unless you search for titanic, i find 330m a very optimistic statement!

[Geo]

Also Mineoro speaks for 1km but is it true???:lol::lol:

[Jeg]

Also Mineoro speaks for 1km but is it true???:lol::lol:




:lol::lol::lol:

[Dubulumach]

BFO type. Sch has errors.
It's not problem to boost amplification - the real art of lrl is to boost precious signal s enough to be sharply detected wihout distrubing S/N ratio. Equivalent noise figure rise with square of two of desired bandwidth. So wide bandwidth collect lot of noise including precius signals of gold coins which would be simply flooded in the noise. Solution is one - narrowband receiver Very narrow. :)

[Geo]

BFO type. Sch has errors.
It's not problem to boost amplification - the real art of lrl is to boost precious signal s enough to be sharply detected wihout distrubing S/N ratio. Equivalent noise figure rise with square of two of desired bandwidth. So wide bandwidth collect lot of noise including precius signals of gold coins which would be simply flooded in the noise. Solution is one - narrowband receiver Very narrow. :)

Hi Dragan.
There is another one solution (as idea)...... play with the level of noise.
Τhink about it...:cool:

:)