Re: Effective "short range" of LRL'S
cz70pro said:
As a first time poster on TN,I will stay netural on the whole LRL topic.However: To those who have used,or have had success with LRL'S can these things "detect" objects only a few feet away? What about searching demolished/torn down houses,abandoned property,etc? Thanks.
cz,
First you need to understand to there are two MAJOR differences and not all LRLs are the same type.
I have explained it here more than twice and here goes again.
There are basically two types of LRLs. The all electronic units and the MFD type units.
The all electronic units feature a sensor element or any kind of receiveing element such as an antenna to identify the fields emanated by long time buried gold or noble metals such as silver, bronze, etc. Those metals when long time buried produce ionization and electric and magnetic fields with specific frequency and phase. These fields may have a span aperture in relation to the vertical axis of almost 180 deg in the case of gold which is the one that has the largest span. Then silver, bronze, and others next. Iron has only 10 to 15 deg of span.
That is why gold is the one metal that can be detected at the largest range.
I have been using these detectors for years in the field. I started using the Mineoro models and later after understanding the concept, I started building my own devices.
In this category falls devices built by Mineoro from Brazil and OKM from Germany among others.
Then we have the MFD type units which employ the concept of molecular frequency discrimination (MFD) that works on the principle of subatomic resonance and excitation of atoms at extremely low level employing magnetics and work on a swivel handle.
These devices aim to detect the element itself and not the field it produces when buried.
Tough it's not my intention to give all details on this aproach now, it generally works by tuning in ONE of the relevant resonant frequencies of an element as none element in the universe has only one frequency but several and several ones.
Depending on how relevant that frequency might be to identify that particular element with accuracy, the antenna swivels to align to the axis of emission and reception that is known by the name of 'signal line' once estabilished.
This aproach can also be used with simple rods conected to a transmitter unit. Rods by the way are the element to 'capture' this since they easily overcome the 'noise', something really troublesome for ordinary and standard electronic aproach.
Tough it's not so difficult building a MFD unit, there are several comercial manufacturers around such as Rangertell, Electroscope, Fitzgerald's, H3tec, etc.
I cannot speak for the other brands, but as I am also a user of a Rangertell Examiner, I can safely say that it's very easy to detect close targets.
I simply set some keys in the calculator which acts as the function generator and this limits the emission and reception range allowing the device's antenna only detect or react or swing to an element in the range choosen.
In the case of the all electronic units, the range and how close the device will detect or beep, depends on several factors such as size of target, how long it's been buried, intensity of fields depending on time of day, weather conditions, etc.
Small targets might be detected from 2 to 30 m or even more depending on conditions, whilst big targets of gold around 1 ton or more can be detected from several miles.
It's not so easy to be able to use the MFD swivel type units since you first need to gather precise balance as any minute move of hands will lead to false indications. Also since your body fields act as a 'trigger' mechanism for the magnetic field responses, any abnormal organic state, nervousness of health problems will interfere with detection at some level.
As an example of an all electronic unit in action, here is our great friend and LRL user Esteban, demonstrating the unit he built.
Here we see the device detecting from about 3 meters (10 feet), a small pile of silver coins buried more than 10 years in his backyard for testing purposes.
Download the files and watch the videos. Notice that not even a large steel or iron plate closeby is able to stop or avoid the emanation.
http://www.geotech1.com/forums/showpost.php?p=100543&postcount=42