VLF Detector Depth Enhancement

[Randy Seden]

I was looking thru some older "Gold Prospector" and "ICMJ" magazines the other night and came across a ad that seemed interesting. It was for a device that had two metal probes that went into the ground and injected an AC current into the earth, which was supposed to cause a "Halo" effect around metals and increase the ability of a VLF machine to pick up 4x the depth. I wonder what would happen if you used the ac output from the VLF machines to drive this device if it would work better (using a FM wireless mike on the VLF detector and a small FM reciver on the ground transmitter so the signal would have the exact frequency and phase?).


I know that you can inject an AC wave into the earth (via earth rods)and use a loop to receive the signal for Induced Polarization Surveys, which might end up to be the new wave of Gold Prospecting as IP is the most accurate method so far (see www.seg.org, goto the Publications section and goto the Archives of "Geophysics" for further info on Induced Polarization-epecially Sept./Oct. 97 issue).


Would appreciate any input on the VLF enhancement idea.


Randy Seden


Simi Valley,CA.

[rick]

Re: VLF Detector Depth Enhancement

hi randy


does article say more specifics ??


how much energy voltage current etc. probably


variable 'cause ground conduction. also on


frequency---the ground conductivity vs freq.


how does it work in theory--the ground being


relatively homogenious produce avg. field


but the metal causes a concentrated flux....


after many hours experiments here in vlf----


and considering the effects as this proposed


hmm--3x depth increase at what cost--the loss of


target id {somewhat subject to orientation and


depth already---) if it really works at all...


you seem to be more technically positioned than


others what you think--you ever design/build vlf


also you speak on pi unit---


my son talk me into another vlf with microprocessor


control..


rick

[Randy Seden]

Re: VLF Detector Depth Enhancement

July 19th,1999


Rick,


I haven't been able to find the magazine that had the ad! I'm still going thru the stacks of ICMJ I was givin (1959-1999,alot of reading!!). If I come across it I'll let you know. Meanwhile I'm putting my efforts into designing and building an Induced Polarization set, as it's the latest and most accurate method used by the Geophysicists for detection of various kinds of ore using the fall time of the return pulse (Gold is around 15 miliseconds or so). Yep, with a 555 and a 100 watt 12volt car stereo amp., you could pump some serious current into the earth. For the receiver, a simple pickup loop into a opamp chain


will do nicely. It's worth putting rods into the earth, knowing your efforts will be rewarded!


Randy Seden


Simi Valley, Ca.

[Carl]

Re: VLF Detector Depth Enhancement

Randy, I've did some experiments with VLF injection a while back. The detector makes really weird sounds, but the short of it is no depth enhancement. Probably hurt depth as it might have shifted the detection threshold slightly.


Would like to know more about IP if you have info.


- Carl

[rick]

Re: VLF Detector Depth Enhancement

Yep, with a 555 and a 100 watt 12volt car stereo amp., you could pump some serious current into the earth. For the receiver, a simple pickup loop into a opamp chain[/i]


>will do nicely. It's worth putting rods into the earth, knowing your efforts will be rewarded!


???---have not read any on this---but do know that


if you dampen the soil to increase conductivity,


(dry soil not too conductive and 1000 v to get currant) and inject


60 hz at some 100-200 volts---rods some 10 feet


apart you can get earth worms to come up in a


very large number-----at least in ohio---


rick