Gold Gun with Gemini III Transmitter

[GOLDEN LILLY]

Hi to everybody, specially to those who are knowledgeable to vlf theories and its application. I have build the gold gun and i have heard that the vlf transmitter where it is tuned to is no longer transmitting vlf signal. So, i used my Gemini III (transmitter) as local transmitter. It transmit 81.92 khz according to the manual. I tuned my gold gun to the same frequency. I am not sure if its transmitter can be used in conjunction with the gold gun. So I ask somebody in this forum to help me the correct procedure in doing the search.
The Gemini has a ground assembly an option in locating a buried pipe with known point. So i use this option via a stainless rod inserting into the ground to transmit the signal. I do not know if i am right on this set-up. So, here are my questions:
1. What is the best way of transmitting a signal into the ground? Is it via a rod or the loop antenna?
2. Is the loop antenna vertical or horizontal? (lying flat in the ground)
3. If I use the loop coil and not the rod, what is the correct procedure for the search?
4. What is meant by "searching" at the edge of the area to be surveyed?
5. What is the estimated distance between the gold gun and the transmitter?
6. At what depth that the transmitter can go underground?

Any help is highly appreciated...Thank you

[FrancoItaly]

I am interested in this topic and when I have more time I will concentrate on this. Check out this link that I found very interesting:
https://borderlandsciences.org/journal/vol/53/n01/Vassilatos_on_Ground_Radio.html

[WM6]

aulook, you can get answer at most your questions, if your test your Gold Gun with about 2m long buried metallic pipe. You cannot test it on single coins or something small like this , cause GG is not able to sense small item on depth. It can sense only bigger deposit/targets at reasonable distance.

What orientation of TR coil/antenna is best in your case, depend on TR/antenna construction and its distance from buried testing target (suggested: pipe). It is about sub-terrestrial wave prospecting and signal polarization. Of course depend on antenna construction and polarization, but most TR tuned antennas can be adapted to real search environment conditions. It is hard to say what distance will be best in your case - you need to check this on selected terrain with testing target buried at reasonable depth (for test between 0.5 and 1m.

Do not use to much TR power, since you get signal-reflective cacophony only!

So, for test: small TX signal, big prolonged buried target, then a lot of antenna distance and orientation checking - this can lead to success.

[GOLDEN LILLY]

Thank you for your good suggestion WM6. I know that you are very knowledgeable in vlf topic. Actually i am looking for Big and not small objects like coins or gold nuggets. I have Gemini III so it came to my mind to try to use its transmitter as local oscillator. I did pick up the signal from my built gold gun but only 3 meters and when i inject the signal into the ground via a ground rod connected to the ground assembly, the gold gun will not sense the signal. So please give me idea what is the correct method of searching using gemini transmitter and gold gun as receiver. Will the gold gun null if it detects a reflected signal from buried object or will its output increase if it also detects a buried object? Sorry for many questions that i asked, i am still studying on this type of method. Thank you..

Regards...

[WM6]

Testing target (suggested 2m metallic pipe) should be buried horizontal not vertical.

More latter I am weekend-moving to another town now.

[Geo]

No reason to use an external transmitter for the GG. If you make a fine tuning to it you can tune it to a strong transmitter (there are so many). If the meter readings more than 120...150 mv then all are ok. But I don't know if you will find something with it.
Also don't tune it at frequencies more than 30 KHz because LM324 can't give the gain of 30.. or more at high frequencies.

:)

[GOLDEN LILLY]

Thank you for the suggestions Geo. I used the Gemini transmitter as local oscillator because i'm not sure what vlf frequency that can be heard in my country. So i downloaded software defined radio the SAQ free software to hear distant vlf transmissions although limited only up to 22 khz. Now i know what frequency to tune to because i hear a steady 5.0 khz 18.3 khz and 20.8 khz. I tuned my gold gun on these frequencies.
I use a dc millivoltmeter with low voltage drop diodes (bridge configuration) since i have no rms ac millivoltmeter. The result is that it is not accurate. I also notice a sudden increase in voltage reading. After investigation, i found out that it is due to distant lightning discharge.

Regards....

[WM6]

Gold Gun apply simplified, but otherwise known and patented principle (still sold in more sophisticated equipment).

Agree with Geo. About 20-30kHz working range could be optimal. If there is no outer existing transmitter signal, we depend on our own movable transmitter.

At least if you use Gemini II TX, it can be easily adapted to work at lower frequency. You only need to add one capacitor in TX tank circuit (about by factor 1.5 of existing Ctx). It can be removed when you wish to use Gemini in its primary function.

Regarding build GG it is all about directivity tuning.

http://i61.tinypic.com/11cbcly.jpg

[Geo]

Thank you for the suggestions Geo. I used the Gemini transmitter as local oscillator because i'm not sure what vlf frequency that can be heard in my country. So i downloaded software defined radio the SAQ free software to hear distant vlf transmissions although limited only up to 22 khz. Now i know what frequency to tune to because i hear a steady 5.0 khz 18.3 khz and 20.8 khz. I tuned my gold gun on these frequencies.
I use a dc millivoltmeter with low voltage drop diodes (bridge configuration) since i have no rms ac millivoltmeter. The result is that it is not accurate. I also notice a sudden increase in voltage reading. After investigation, i found out that it is due to distant lightning discharge.

Regards....
You must use a true rms meter. If you have not one then there are simple chips that are full true rms voltmeters. You can see the LTC1968.

[GOLDEN LILLY]

Thank You WM6 and Geo for your help. Now i understand clearly this type of detecting method. All i have to do now is to tune the gold gun to a correct frequency and see if it has a promising result. My other concern is how will i know if i detected a reflected signal? Will the gold gun nulls or will it give an increase in output voltage?

[Agraz]

you can use the transmitter to the black antenna of the Garret Master Hunter, I heard the vlf tone from the Garret in the Gold Gun at a distance of 30 meters

[Agraz]

You can use this configuration in page 9: manual pdf Magnacast 5000

http://www.gold-ftgusa.com/SiteFiles/ProductsFiles/document/FT9001-ar.pdf

English manual already removed in internet

http://www.longrangelocators.com/forums/showthread.php?t=13089&page=5

I will try to prove someday think it should work

[GOLDEN LILLY]

I have tried the idea of reflective detection using Gemini III Tx with my home made gold gun But i cannot determine if i have the reflective signal. It needs more experimenting...
I used Magnacast type detecting reflective signal for the test but again no result yet.

[WM6]

Only at bigger deposits in soil you can sense reflective signal, not at small target as coins.

[Geo]

I have tried the idea of reflective detection using Gemini III Tx with my home made gold gun But i cannot determine if i have the reflective signal. It needs more experimenting...
I used Magnacast type detecting reflective signal for the test but again no result yet.

The power of Gemini is very low for creating a secondary magnetic field from buried targets.

[GOLDEN LILLY]

I agree with you Geo. Gemini III tx has very small transmission power to create secondary magnetic field to long time buried objects. So what is your suggestion? What kind of vlf transmitter and antenna do I use to penetrate deeper?

[WM6]

You should learn how antenna works first.

Gold Gun is not metal detector (which is based on near field transmission), so big TX power is here irrelevant (in most cases even destructible to our goal).

Gold Gun is based on (mostly weak) far field signal transmission and should be tuned in adequate way to work properly.

For those interested, I will be honest and post this basic infos again:

http://www.longrangelocators.com/forums/showpost.php?p=153338&postcount=14

http://www.longrangelocators.com/forums/showpost.php?p=153342&postcount=16

[GOLDEN LILLY]

Do you mean Gold Gun does not work as advertise? or it cannot work under any circumstances whatsoever except reflective method of locating objects?

Any suggestion on the kind of transmitter to be used for reflective method? Is gemini III transmitter enough?

[WM6]

Do you mean Gold Gun does not work as advertise? or it cannot work under any circumstances whatsoever except reflective method of locating objects?

Any suggestion on the kind of transmitter to be used for reflective method? Is gemini III transmitter enough?

Properly tuned and used

http://www.longrangelocators.com/forums/showpost.php?p=153334&postcount=12

Gold Gun works, but not for small things, like coins (except from vicinity in metal detector way). It works from reasonable distance (in meters) for bigger (metal or ore) deposits in soil only.

Mostly of others commercial LRL creation (in contrast to Gold Gun) doesn't work at all, or work in deceptive way only.

More TX power mean more disturbance from TX source (more parasite modulation signals, more harmonics) more EMI and more unwanted multiple cross-reflections from environment. With more power you get more signal cacophony only.

So better to stay in safe zone under 1W TX power and be more engaged with adequate positioning (regarding location and antenna polarization) of TX transmitter in regard to search micro location and proper GG search orientation. No matter which transmitter you use (as well as Gemini II) your Gold Gun should be tuned to the same frequency.

This is simple 9-12V transmitter solution (L1 is about 20 turns on 30x30cm Styrofoam body):
http://www.talkingelectronics.com/projects/200TrCcts/MetalDetectors/images/Image7of%20PartII.gif

[GOLDEN LILLY]

Thank you for the suggestion WM6. I have questions on using a transmitter for gold gun.

First, in the schematic you gave above, how far the signal can go vertically and horizontally?
Second, what position is the transmitter with respect to the gold gun?
Third, if i tune my gold gun receiver to the frequency of the transmitter, how will i know i have detected the signal? Do i need modulation?
Fourth, what is the best antennna of the transmitter do i use, a coil or via ground rod?
Fifth, if my gold gun detected a reflection from buried object, will it display an increase or decrease (null) in my output signal?
Regards.....

[WM6]

First, in the schematic you gave above, how far the signal can go vertically and horizontally?

Using proper tuned and proper wavelength antenna (par example 1/4 lambda), with 1W your signal can travel around globe (do not use it at distances lower than 10m, even with couple of mW of TX power). So no problem with kilometer of distance.

Second, what position is the transmitter with respect to the gold gun?

At least mentioned 10m distance (better more) and as next important step you need to search for active propagation, by moving (angling and rotating) TX antenna first, along with using artificial target (par example 30cm dia metallic plate on ground).

Third, if i tune my gold gun receiver to the frequency of the transmitter, how will i know i have detected the signal? Do i need modulation?

Usually it will be enough inter-modulation with interference signals, but it is useful to use additional pointer meter or LED along with earphone.

Fourth, what is the best antenna of the transmitter do i use, a coil or via ground rod?

Coil antenna, like those with PI or BFO detectors (it should be flexible to set best propagation position). Best propagation will be easier to set with bigger TX distance from search field.

Fifth, if my gold gun detected a reflection from buried object, will it display an increase or decrease (null) in my output signal?

Both, where signals (from notable signal to null or vice versa) changes suddenly, detecting from both opposite direction, positioned GG antenna direction at 90° angle to Transmitter, there will be more chances for bigger metallic deposit under ground.
So you need to follow repetitive very rapid changes in signal. Slow changes are not indicative for our needs.

Regards..... tx

[taxma1981]

Properly tuned and used

http://www.longrangelocators.com/forums/showpost.php?p=153334&postcount=12

Gold Gun works, but not for small things, like coins (except from vicinity in metal detector way). It works from reasonable distance (in meters) for bigger (metal or ore) deposits in soil only.

Mostly of others commercial LRL creation (in contrast to Gold Gun) doesn't work at all, or work in deceptive way only.

More TX power mean more disturbance from TX source (more parasite modulation signals, more harmonics) more EMI and more unwanted multiple cross-reflections from environment. With more power you get more signal cacophony only.

So better to stay in safe zone under 1W TX power and be more engaged with adequate positioning (regarding location and antenna polarization) of TX transmitter in regard to search micro location and proper GG search orientation. No matter which transmitter you use (as well as Gemini II) your Gold Gun should be tuned to the same frequency.

This is simple 9-12V transmitter solution (L1 is about 20 turns on 30x30cm Styrofoam body):
http://www.talkingelectronics.com/projects/200TrCcts/MetalDetectors/images/Image7of%20PartII.gif

This circuit work from 35-50 khz :)
The gold gun range it is 0-30 khz

[WM6]

This circuit work from 35-50 khz :)
The gold gun range it is 0-30 khz

As already pointed, both devices: receiver (GG) and transmitter (above posted example) should be set at the exactly same frequency.

Using proper LC components, both devices: receiver (GG) and transmitter (above TX example), could be set (tuned) at desired frequency from say: about 20kHz to 40kHz.

Suggested working frequency here is 30kHz for both devices, but arbitrary frequency in above mentioned range could be set using proper L and C in tank circuits.

With schematic (without using crystal controlled oscillator) we can get indicative values of LC only, exact frequency should always be set by proper LC values of our actually used components.

Genuine GG AL-718 is working at fixed frequencies: 9,5kHz, 19,2kHz, and 27kHz (not 0-30kHz). GG working frequency is easily changeable by changing "USA" capacitor to other value that suit to TX (or vice versa: we can adapt TX tank circuit to suit to one of GG frequencies).

[taxma1981]

As already pointed, both devices: receiver (GG) and transmitter (above posted example) should be set at the exactly same frequency.

Using proper LC components, both devices: receiver (GG) and transmitter (above TX example), could be set (tuned) at desired frequency from say: about 20kHz to 40kHz.

Suggested working frequency here is 30kHz for both devices, but arbitrary frequency in above mentioned range could be set using proper L and C in tank circuits.

With schematic (without using crystal controlled oscillator) we can get indicative values of LC only, exact frequency should always be set by proper LC values of our actually used components.

Genuine GG AL-718 is working at fixed frequencies: 9,5kHz, 19,2kHz, and 27kHz (not 0-30kHz). GG working frequency is easily changeable by changing "USA" capacitor to other value that suit to TX (or vice versa: we can adapt TX tank circuit to suit to one of GG frequencies).


I meen the circuit from gold gun can tuned at this range 0-30 khz....


we can have better results in this transmitter?

[WM6]

I meen the circuit from gold gun can tuned at this range 0-30 khz

It can be tuned to 40kHz or even 50kHz too - no problem.

Genuine GG is set to 3 fixed frequency not for 0-30kHz as you wrote (and later "mean").

[taxma1981]

It can be tuned to 40kHz or even 50kHz too - no problem.

Genuine GG is set to 3 fixed frequency not for 0-30kHz as you wrote (and later "mean").


Οκ :)

[taxma1981]

we can with a radio (AM band) and a transmitter (AM band) to detect metals and gaps?

[WM6]

Theoretically yes.
It is problem with antenna directivity. Ordinary AM radio ferrite antenna does not provide enough directivity for such purpose.
Proper tuned GG antenna can be set to high directivity. GG antenna has a much larger potential in its construction.

[taxma1981]

Thanks!!!!! The gold gun real work ,3 times i locate copper:)

[abdou2014]

How can I calibrate GG at 250 Khz, The highest frequency I have succeeded is 90 Khz ?

[WM6]

How can I calibrate GG at 250 Khz, The highest frequency I have succeeded is 90 Khz ?

Along with changing C part of tank circuit, you need less turns (about 2x100 turns) on ferrite rods.

For good results it is better to stay under 100kHz. Suggested frequency is about 30kHz.

[abdou2014]

Thank you WM6 .

[taxma1981]

This is gut for transmitter wm6?

https://s16.postimg.org/bo1rjdglx/15182487_10154985755059396_1991726861_o.jpg

[GOLDEN LILLY]

Taxma, when you find the copper 3 times with your gold gun, what is the reading of your millivolt meter high or low value? And what is the distance?

[GOLDEN LILLY]

Wm6, i plan to use an AM radio as a receiver for my AM transmitter. AM radio is more precise and selective as a receiver, my question is, can i use the antenna of gold gun in the AM receiver?

[taxma1981]

The distance 10 meter and the reading from meter 150-480 mv

[WM6]

Along with changing C part of tank circuit, you need less turns (about 2x100 turns) on ferrite rods.

For good results it is better to stay under 100kHz. Suggested frequency is about 30kHz.

Sorry cannot access: "Gateway timeout" return only.

[WM6]

Wm6, i plan to use an AM radio as a receiver for my AM transmitter. AM radio is more precise and selective as a receiver, my question is, can i use the antenna of gold gun in the AM receiver?

Simple replacement will not work. You need to adapt GG antenna along with input antenna amplifier to one of frequencies between 500 and 1600kHz (due inter-frequency mixer limitation used in AM radio). Such high frequencies are good for detecting shallow gold dust, but soil penetrating is relatively poor. Better to stay with 30kHz. Selectivity can be improved with good GG antenna tunning (by proper setting its directivity on free in field away from different disturbances and not in lab).

[abdou2014]

Please How to connect a loop antenna in place of the telescopic antenna ???

[WM6]

http://i66.tinypic.com/330z3ag.jpg

[abdou2014]

Thank you WM6 , According to the picture :
L1 must have more turns than L2
L2 and loop antenna has not ground connection

[WM6]

L1 must have more turns than L2


Yes, for L2, about 2 turns of 2mm wire in diameter are enough.

For L1 number of turns depend on used ferrite, C, and working frequency. Data should be given on link where you got this TX end schematic.

For loop antenna diameter of wire used can be smaller than 0.2mm, but sum of total intersection of all loop antenna turns should not be less than intersection of L2 wire.

The same rule is for L2 regarding L1. Intersection of L2 should not be less than sum of
intersection of all turns of L1.

But calculation of L1 should be first. L1 tank circuit should resonate at you chosen working frequency.

The follow L2 and at the end Loop antenna.

This is, if we go complicated way, which is not needed (except if we need ferrite transformation for balanced impedance to antenna input).

We can go more simple and wound L1 as Loop antenna, as it was primary intention.



L2 and loop antenna has not ground connection

Not in those case.

[abdou2014]

Thank you for relpy :)

[taxma1981]

Thank you for relpy :)

Where are you from my friend,?i am from greece and i have strong signal in greece from germany,france and italy..you dont need transmitter

[taxma1981]

This is a area target,i detect this point from 100 meter distance with my gold gun,25 bronze coins

https://s21.postimg.org/5jiakv9r7/image.jpg (https://postimg.org/image/5jiakv9r7/)

[WM6]

Taxma1981, you are a magician. 25 bronze coins at 100m - wow!!!.

Do you sell something?

[taxma1981]

I think i don t detect the 25 coins,this area 10×10 meter have more coins...i have a special ferrite antenna:lol:

[GOLDEN LILLY]

Taxma, what special ferrite do you have? Please give me information. I bought ferrite rod from Latvia on ebay. The size is 10mm diameter and 7.5 inches long. I experimented the number of turns and wire gauge. I clearly hear my analogue watch ticking from several inches. My problem now is the RMS converter and LCD display which is not available in my place. So, i intend to use spectrum analyzer apps for visual indication. The vlf Signal in my place is weak. I just hear the signal clearly last December 2016 but now no more. So i made a signal generator as transmitter based on the above schematic but lacks the distance because i have a little idea on the matched antenna for the circuit.
Please give information on your special ferrite. My email is errel74@yahoo.com.

[abdou2014]

Hi GOLDEN LILLY, please what sort of antenna do you use in your transmitter ?

[GOLDEN LILLY]

Hi Abdou, i am still experimenting on my transmitter. I used the above posted tx schematic. I am not sure if i got the correct or matched antenna because i am not an expert. I need more information and complete details for the correct tx power. I connected my coil directly from the output instead of through ferrite core transformer which is i think a wrong.
Here is my Gold Gun Transmitter....

[abdou2014]

Thanks nice job, can you poste the schematic of TX circuit pls ?

[GOLDEN LILLY]

I will give you the schematic through your email. I cannot post it without the permission of the owner who is a member of this forum.

[GOLDEN LILLY]

WM6, is loop antenna different from L2? What do you mean by intersection of loop antenna and L2? I need more clarification please....

[abdou2014]

faycal_44@yahoo.fr

[taxma1981]

Taxma, what special ferrite do you have? Please give me information. I bought ferrite rod from Latvia on ebay. The size is 10mm diameter and 7.5 inches long. I experimented the number of turns and wire gauge. I clearly hear my analogue watch ticking from several inches. My problem now is the RMS converter and LCD display which is not available in my place. So, i intend to use spectrum analyzer apps for visual indication. The vlf Signal in my place is weak. I just hear the signal clearly last December 2016 but now no more. So i made a signal generator as transmitter based on the above schematic but lacks the distance because i have a little idea on the matched antenna for the circuit.
Please give information on your special ferrite. My email is errel74@yahoo.com.



Try with more turns 500+500 or more,i use 2 ferrite 15cm

[WM6]

WM6, is loop antenna different from L2? What do you mean by intersection of loop antenna and L2? I need more clarification please....

Intersection mean surface of intersected wire in square mm (mm2) or Cross sectional area.

par example:

If L2 is 1 turn coil of wire 3mm in diameter and Loop antenna is 200 turns of wire 0.22mm in diameter, if converted in Cross sectional area:

1T/3mm=1x7mm2=7mm2 < 200T/0.22mm=200x0.04mm2=8mm2

so if we compare Cross sectional area: 7mm2 < 8mm2

This suit to rule that total of Cross sectional area of Loop antenna should not be less than Cross sectional area of L2.

[GOLDEN LILLY]

WM6, thank you for your explanation. However, i still do not understand the coil construction. Is the secondary winding the loop antenna itself? or there is another loop coupled in the said secondary winding? Please make a drawing...

[WM6]

WM6, thank you for your explanation. However, i still do not understand the coil construction. Is the secondary winding the loop antenna itself? or there is another loop coupled in the said secondary winding? Please make a drawing...

There is drawing in post #40.

Loop antenna is connected to L2 (output L2 wire to input loop antenna wire).

But this was only explanation to abdou2014 previous question and as I say, it is practically nonsense to connect loop antenna this way (in contrary to telescopic antenna).

Loop antenna can be (much better) connected instead of L1 (L1 act in this case as loop antenna). Of course in this case L1 should be wound (dimensionally and by other parameters) as loop VLF transmitting antenna (and not as one simple inductor).

[abdou2014]

What is the position of the ferrite antenna and a telescopic antenna transmitter for nulling ?

[abdou2014]

I want to add an emitter :)

[GOLDEN LILLY]

WM6, your implying that a loop antenna without an inductor is far more better than with an inductor. So if this is the case, please can you recommend loop size and windings and wire diameter? My loop antenna is a rectangular in shape with 26 turns, # 22 AWG directly connected from the output of the power transistors without ferrite. I based my antenna shape from magnacast lrl. Please comment.

[GOLDEN LILLY]

Abdou2014, i am still looking the transmitter schematic from my files. I forgot what folder i saved it. Just give me time. Anyway, you have a very nice gold gun.

[abdou2014]

thank you , i'm waiting :)

[WM6]

WM6, your implying that a loop antenna without an inductor is far more better than with an inductor. So if this is the case, please can you recommend loop size and windings and wire diameter? My loop antenna is a rectangular in shape with 26 turns, # 22 AWG directly connected from the output of the power transistors without ferrite. I based my antenna shape from magnacast lrl. Please comment.

Loop antenna is an inductor too (air core inductor).

Your antenna could be OK, you need to manage it to desired frequency by proper capacitor set in antenna tank circuit. Better way by try and measure.

[GOLDEN LILLY]

Thank you WM6. I will Make a trial and error for my coil. Anyway, what frequency should i use for my gold gun transmitter. Should i also need to modulate my transmitter?

[abdou2014]

NEW TX

[abdou2014]

:)

[GOLDEN LILLY]

Hi Abdou. Please tell us about your new transmitter...What are the component values?

[abdou2014]

I have not yet finished, I do experiments , pls WM6 What are the best antennas for a transmitter, telescopic or loop ?

[WM6]

With loop antenna you can acheive better (desired) wave propagation and (possibly) direction to avoid unwanted reflexy from objects out of your interest.

[abdou2014]

Thank you WM6 , The blind spot ( nulling ) does not disappear with a powerful transmitter loop ?

[abdou2014]

When I turn on, the frequency changes and slowly decreases, is there a way to stabilize it ?

[WM6]

After about 10 min it should be temperature stabilized.
In case that outer temperature sources, like sun/shadow, destabilize your circuit,
(multiple) potting your board in paraphine can help.
Paraphine is great temperature insulator and temperature changes compensator.

[abdou2014]

Thank you WM6 , I noticed that even after 10 minutes the frequency is not stable , I mixed TX totem with this circuit I have a stable frequency. :)

[abdou2014]

circuit + pcb

[abdou2014]

Please how to build a 33 Hz receiver antenna , loop and ferrite , and what are their characteristics ???

[reza vir]

Please how to build a 33 Hz receiver antenna , loop and ferrite , and what are their characteristics ???

hi abdou
You can by reading the pdf
Make the desired antenna

[reza vir]

The following site may help to calculate

http://www.radiobrandy.com/dipole1.html

https://www.willus.com/author/antenna.shtml

[abdou2014]

Thank you .

[Agraz]

the gemini receiver has a loop antenna inside, I think the copper wire can be wound into thick ferrite, and gold gun is no longer needed.