Need help with building a LRL

coyote3

Full Member
Apr 12, 2012
160
26
Wyoming
Detector(s) used
Whites XLT Spectrum,
Minelab Xterra 705,
Whites TM808,
Bounty Hunter,
Si Go by Fitz
L Rods
Primary Interest:
All Treasure Hunting
I want to build an LRL which I can set to do any different frequencies. I was told a DDS frequency generator and build my own ground probes would work great most of the time.

Either that or has anyone heard of using an energized coil and setting the element on top of it to do the same?

Thanks for any info
 

Darke

Sr. Member
Aug 16, 2018
314
253
Central Florida
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Garrett At Pro
Primary Interest:
Metal Detecting
Either of would work. Building your own to allow frequency to be set easily by switch would be the fastest set up. DDS would be the most inclusive. A Picberry is ideal if your electronic abilities allow it. Ground probes can be tied to a binding post like a certain company does with theirs or use copper/brass and make your own probes.Carl Moreland has simple probe plans on his site. One of the probe units I made for testing used a powered coil and bait chamber for resonance. The testers liked it but the group was small and localized so still not sure about it.
 

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coyote3

Full Member
Apr 12, 2012
160
26
Wyoming
Detector(s) used
Whites XLT Spectrum,
Minelab Xterra 705,
Whites TM808,
Bounty Hunter,
Si Go by Fitz
L Rods
Primary Interest:
All Treasure Hunting
I guess I may not be electronic able if I do not know what a picberry is? I am somewhat savvy but have not heard of that. So is there a specific DDS unit to get or will about any of them work? Thanks again
 

Darke

Sr. Member
Aug 16, 2018
314
253
Central Florida
Detector(s) used
Garrett At Pro
Primary Interest:
Metal Detecting
That's definitely a good reason not to know if you can build one lol. A picberry is a Raspberry Pi controlled combination oscilloscope and function generator. It uses a 32 bit micro controller(PIC) to create and read waveform and a DAC to generate analog output. The Raspberry Pi generates the video signal for display. The PIC is large enough it's pretty easy to solder. There are detailed plans here ECE 4760 Digital Oscilliscope and Function Generator

All modern cheap DDS generators are close to the same and are pretty precise due to the NCO chips used. The downside is they can take some time to enter the frequency you want unless you use a test bench model. Older analog models tend to be a bit more powerful but can have bad THD in the output.
 

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OP
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coyote3

Full Member
Apr 12, 2012
160
26
Wyoming
Detector(s) used
Whites XLT Spectrum,
Minelab Xterra 705,
Whites TM808,
Bounty Hunter,
Si Go by Fitz
L Rods
Primary Interest:
All Treasure Hunting
So I should be able to make one of Carl's probe sets and connect to the Q 9 cables and sets some frequencies and do some testing with samples? Would you by chance know how to make a power enhanced set of l rods to use in conjunction.? Thanks again
 

Darke

Sr. Member
Aug 16, 2018
314
253
Central Florida
Detector(s) used
Garrett At Pro
Primary Interest:
Metal Detecting
That's pretty much it in a nutshell. BNC connectors are just 2 terminal and you can either build or buy BNC to whatever terminal you want to use. BNC to alligator clips are cheap. If you want just a voltage increase in the rods simple L rods with the TFR-4 voltage box in the other thread will work fine. Just connect the leads to each of the rods.
 

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