Geotech
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What's New
02/18/12 - Patents added (Metal Detector/Patents)
07/28/10 - Colorado Gold Sticks report (LRL/Reports)
01/07/10 - Article on LRLs and eBay Feedback (LRL/Info)
12/31/07 - Geotech now has its own domain name, www.geotech1.com.
12/21/06 - Article on making fast PI coils (Metal Detector/Projects)
11/06/06 - Add'l Schematics posted (Metal Detector/Schematics)
08/20/06 - Article on Coil Basics (Metal Detector/Info)
08/10/06 - Article on Induction (Metal Detector/Info)
05/23/05 - Notes on Bill Floto's LRL (LRL/Reports)
03/13/05 - All-new forums!
12/31/04 - Created a database of coil parameters (Metal Detector/Info)
12/10/04 - Added Jim Koehler's proton mag report (Magnetometer/Info)
12/10/04 - Updated the various Magnetometer sections (Magnetometer)
12/06/04 - Patents added (Metal Detector/Patents)
11/19/04 - Ranger-Tell Examiner report (LRL/Reports)
06/06/04 - Updated Hammerhead PI page, added SMT files (Metal Detector/Projects)
05/20/04 - Updated Hammerhead PI page (formerly PI-1 project), added Gerber files (Metal Detector/Projects)
04/09/04 - Updated the Resources Page (added some good PIC links) (Misc/Resources)
04/09/04 - Jim Thomas lawsuit report (LRL/Info)
04/01/04 - Electroscope 301 report (an appropriate item for April Fool's Day, eh?) (LRL/Reports)
03/27/04 - "Matchless Metal Locator", by Thomas Scarborough (Metal Detector/Projects)
02/15/04 - Treasure Scope "Quad" report (LRL/Reports)
01/05/04 - "Build the Frisker", by Sheets & Graf (Metal Detector/Projects)
12/16/03 - Added a "References" page to all the major sections of the web site.
12/02/03 - "Construction of Coplanar Search Coils", by Dave Emery (Metal Detector/Projects)
11/25/03 - "Build an Induction Balance Metal Locator", by John Clarke (Metal Detector/Projects)
11/21/03 - "Build You Own Sonar System", by Lou Garner. (Geophysics/Projects)
10/27/03 - "Build a Metal Locator", by Robert Kreiger (Metal Detector/Projects)
10/14/03 - Misc Metal Detector Circuits, by Charles Rakes (Metal Detector/Projects)
09/25/03 - ETI561 crystal BFO, by Phil Wait (Metal Detector/Projects)
09/09/03 - 2-part article on detector circuits, by Charles Rakes (Metal Detector/Projects)
08/26/03 - Posted rev 0.8 of the PI-1 project article (Metal Detector/Projects)
08/10/03 - Lots of patents added
08/08/03 - "Simple, Sensitive Geiger Counter" by David Tilbrook. (Geophysics/Projects)
07/21/03 - ETI1500 article posted, pretty good VLF/TR design (Metal Detector/Projects)
07/11/03 - "Revealer" article posted (Metal Detector/Projects)
06/09/03 - Commercial schematics page added (Metal Detector/Schematics)
06/08/03 - LectraSearch X-60 report (LRL/Reports)
06/01/03 - "All About Batteries" (Misc/Info)
05/30/03 - Dowsing for Raffle Tickets (LRL/Info)
05/29/03 - "Tools & Techniques in Radiometric Exploration" by Malcolm J. Plunkett. (Geophysics/Info)
05/09/03 - Scantrak 18 Golf Ball Finder, funny look at another scam. (LRL/Reports)
05/08/03 - Posted rev 0.7 of the PI-1 project article, plus Option 2 (Metal Detector/Projects)
04/29/03 - ETI549 Induction balance project, Australian version (Metal Detector/Projects)
04/28/03 - Posted rev 0.6 of the PI-1 project article (Metal Detector/Projects)
03/28/03 - Deep-seeking metal locator, by Wait & Harrison (Metal Detector/Projects)
03/12/03 - Posted rev 0.5 of the PI-1 project article (Metal Detector/Projects)
03/09/03 - "Expermenting With Magnetic Sensors", by Joseph J. Carr (Magnetometer/Info)
02/20/03 - Electroscope Model 20 report (LRL/Reports)
02/20/03 - Earth resistivity meter (from ETI) posted (Geophysics/Projects)
02/18/03 - New parts-placement diagram for PI-1
02/07/03 - "Exploration Archaeology" article posted (Geophysics/Info)
02/05/03 - Posted rev 0.3 of the PI-1 project article (Metal Detector/Projects)
01/23/03 - Posted "Houndog" IB project article (Metal Detector/Projects)
01/21/03 - Posted rev 0.2 of the PI-1 project article (Metal Detector/Projects)
12/18/02 - Posted alpha rev of the PI-1 project article (Metal Detector/Projects)
11/14/02 - Magnetometer article by Lawrence (Magnetometer/Projects)
10/31/02 - Proton Magnetometer article by Marriner (Magnetometer/Info)
09/30/02 - Seriously major overhaul of the Geotech web site.
07/30/02 - Added section for patents pending on the patents page.
06/27/02 - Inside the LectraSearch report (LRL/Reports)
12/06/01 - Inside the Electroscope report (LRL/Reports)
12/06/01 - VR-800 Addendum (LRL/Reports)
12/04/01 - LRL Challenge.
08/22/01 - Posted "Underground Survey Meter" by Harold Pallatz.
08/03/01 - Posted "History of Metal Detectors" by Roy Roberts.
07/29/01 - Popular Mechanics article showing a WWI mine detector (History).
07/29/01 - Added a new "History" page to metal detectors.
07/22/01 - Dowsing/LRL Q&A.
06/24/01 - Posted P.J. Wales' "Sandbanks" PI detector.
05/19/01 - Posted Mark Stuart's "EE Treasure Hunter" PI detector.
04/29/01 - More patents, also corrected Delphion links.
04/28/01 - Posted "Metal Detection" (basics).
03/27/01 - Inside the VR-800 report (LRLs).
03/22/01 - Coil Winder project.
02/27/01 - More patents...
02/23/01 - "Electronic Metal Locators" by Don Lancaster.
12/28/00 - Posted "ETI 549" IB detector.
11/15/00 - Posted "Shadow" VLF/TR-disc. detector from ETI.
11/15/00 - Posted 150dpi version of the Huggard Mag.
10/27/00 - Posted the Huggard Proton Magnetometer design.
10/24/00 - Gerhard Fisher patent (1937) added.
10/14/00 - Twin Loop Treasure Seeker (PI) by Robert & David Crone.
09/28/00 - Part 3 of the Magnum IB article added. Parts 1 & 2 reformatted.
08/17/00 - GoldPic PI detector by Trevor Hill.
07/25/00 - PLL detector by Kamil Kraus.
06/26/00 - More patents.
05/26/00 - How to use a sluice article posted (Misc).
05/26/00 - Updated links in most sections.
05/23/00 - Induction Balance detector by Andrei Chtchedrine.
05/23/00 - Patents can now be downloaded in PDF format.
05/22/00 - Posted "How to Build a Dry Washer" in the Misc section.
04/16/00 - Rev 1.2 of Fluxgate Magnetometer article, new sensor mounts.
04/08/00 - Posted article on multilayer air-cored coils.
01/25/00 - Minor revisions to "Building LRLs" and "Build an MFD".
01/11/00 - Rev 1.1 of Fluxgate Magnetometer article, minor clarifications.
01/10/00 - Corrected circuit for "Build an MFD".
01/09/00 - Posted preliminary "Build an MFD".
01/09/00 - Updated "Building LRLs".
12/11/99 - Added a Statistics Calculator in the LRL section.
12/02/99 - MFD offer posted.
11/06/99 - Gavin Cheeseman's Metal Detector article, Part 2 posted.
10/23/99 - Gavin Cheeseman's Metal Detector article, Part 1 posted.
10/16/99 - Final version of my Fluxgate Magnetometer article posted.
09/30/99 - Revised version of my Fluxgate Magnetometer article posted.
09/19/99 - Preliminary version of my Fluxgate Magnetometer article posted.
09/12/99 - Gavin Cheeseman's Magnetometer article, Part 2 posted.
09/07/99 - Gavin Cheeseman's Magnetometer article, Part 1 posted.
08/16/99 - Correction to Magnum IB design.
08/05/99 - Magnum IB design (VLF/TR disc) posted.
07/31/99 - The mapdowsing contest has now begun!
07/21/99 - Set up the Side Scan Sonar project, volunteers wanted!
07/21/99 - Posted PIC code for the Stuart PI design. Thanks, Mark!
07/15/99 - Posted the "Phaser" TR design.
07/14/99 - Part 2 of the Corbyn PI article is finally up. I will, sometime in the near future, rescan part 1 and combine everything.
07/13/99 - Reformatted and expanded the patents list.
06/20/99 - The Tech Forum now supports image uploads. Please click the FAQ or Help in the Post-form for more details.
06/13/99 - PC Board techniques posted (Misc section).
06/08/99 - Mark Stuart's Microcontroller PI design posted.
06/06/99 - Added some misc stuff to the Misc page, mostly DIY projects.
05/27/99 - Buccaneer IB design posted.
05/12/99 - Earth Resistivity Meter, Part 2 posted.
05/11/99 - Earth Resistivity Meter, Part 1 posted.
05/04/99 - Coinshooter IB design posted.
05/01/99 - Jetco Treasure Hawk design posted.
04/27/99 - Posted the EDN BFO design.
04/21/99 - Posted a two-box IB design.
04/20/99 - Finally got a BFO theory paper done.
04/16/99 - It's not quite finished, but I added the "Building LRLs" writeup. So build yourself an L-rod, grab a shovel and dig, and then make up your very own theory of empty holes.
04/15/99 - Updated the patents list.
04/14/99 - Posted the ProScan PI detector.
04/08/99 - Added a new Patent listing in the Resources page.
04/04/99 - Posted Corbyn's PI article from Wireless World.
03/30/99 - Added a few more links. Especially check out Dan's Sidescan Sonar page, very interesting.
03/24/99 - This Web page is officially up and running, much thanks to Christian Neumann!
03/12/99 - Unofficial, preliminary preview. There is much to do...