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Squelch, free energy & directional antenna
Squelch is the button of a radio or scanner for muting the speaker if there is only "white noise" present, so that you will hear only if somebody sends a signal or message.
Free energy in our case is simply electromagnetic radiation you can receive with some antenna and converting it to very weak voltages. And finally a directional working antenna is the non-plus-ultra if the LRL is able to work at all! Especially needed with small items far away, like a golden ring at 10m distance. What I want to explain is the following: With a good sqelch you are able to discriminate the usual! background zhzhzhzhzhzhzhzhz aka white noise, but if even this noise has much energy (like EM-distortions etc. has), the speaker will turn on. What we are needing is the most sensitive electronical signal distinction related to metal! Compare it with a good amateur radio where you can receive a station from 10.000km away that is sending by just a half watt of power. And it would be possible to send it with some milliwatt, if the directional would work like as with laser-beams. One ray of light with a power of some pikoWatt or below can travel thousands of lightyears. But also the receiver has to be very good to distinct very weak radio-stations from the noise. Keeping all this in mind now we just need to know with what kind of radiation buried metal reacts in the most sensitive way. This is not a question if 5kHz or 15kHz is better for ground penetration, it has to do with the reception systems we want to use. One of them is the ion-chamber that seems to be extremly sensitive if well build, a second may be the electrostatic-receiver (we have to proof it first) and the third working is the "passive receiver" that seems to recognise a change of the electromagnetic energy of an area. But I don't wanna say that "receiver only" is the best solution in LRL. We just have to find a way that really works like radar or similar so it causes the metal object to radiate back, but from a much longer distance as usual detectors do! For wireless energy http://en.wikipedia.org/wiki/WiTricity http://en.wikipedia.org/wiki/Magnetic_loop special coils are use and maybe we should use the same instead flat round coils like MDs do. However the receiver has to be extremly sensitive to detect smallest changes in em-field-strenght like gradiometers do at magnetical level - combined with a really good working directional antenna. A zoom antenna would be the best, but I don't know if such exist - working like a tele for cameras. if yes it would work like treasure detection by infrared radiation from the ground. The best would be finding some radiation our LRL sends out that the buried metal really reflects, sends back or transforms it into some other recognisable "effect"! |
#2
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Quote:
Defining the signal to measure implies you first know what signals exist in the location of buried metal. Or alternately, you should know how signals sent to locations of buried metal react in a way that can be measured above the background noise. To make it more clear, there are only two approaches to detecting buried metals: 1. A passive detector that detects signals existing in the area of buried metal. This kind may have active power elements inside it, but it is only designed to detect outside signals, not to transmit anything. 2. An active detector that sends out some kind of signal, then measures some kind of signal returning as a result of what it sent out. In this case the signal detected may be the same signal sent out which is changed in some way by the buried metal. Or it could be a different signal that appears as a result of the signal that is sent out. There are hundreds of examples that could apply to locating buried metals from either of these approaches. Here are a few examples
But how can you choose what signal to detect? We can look in the Remote Sensing forum for suggestions that have been given by people who claim to build working LRLs: Some suggestions of signals to detect given by LRL builders:
When I actually asked what is the best signal to try to detect, I got very little response other than measure the voltage in the air, and pressurized gas can come from a buried treasure location: http://www.geotech1.com/forums/showthread.php?t=15605 Maybe you can think of a better signal to build metal detecting equipment for. Best wishes, J_P |
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