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Originally Posted by Mike(Mont)
In my years of locating, NOTHING compares to a signal line when it comes to discriminating. Even with an MFD/HID, if you just use the sweep technique instead of crossing/tracing the signal line, you are not getting the physical discrimination, just mental discrimination. That may or may not get you to the target. The signal line IS the discrimination. Yes, I own an Examiner and I don't use it any more, not even with an MFD. Not saying it can't work ,just that it is not that consistent. Even a signal line is not always going to be accurate. Sorry Hung, this thread is about the Magnacast. I repeat, please start a new thread.
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I agree. What does an Examiner have to do with forward gauss? There are plenty of threads in this forum for Examiner posts. Take your pick and post there.
But, since when has anyone thought twice about hijacking threads at Geotech?
Maybe this is why it takes a few hours to track down the fragments of information about any particular topic in Remote Sensing forum.
Getting back to the Magnacast 5000, a new thought is emerging that helps to explain LRL theory in general. From what I gather in Mike(Mont)'s last few posts, the signal generator in the Magnacast 5000 as well other Vernell Electronics signal generators do not discriminate metals or broadcast RF for any measurable distance. In theory, the small square wave signal is so weak it is barely detectable unless there is some metal that also has some very weak mechanical (molecular level) vibration with electrical artifacts. As the theory goes, the weak electronic square wave signal and weaker electronic artifacts from the metal are both undetectable alone when using ordinary electronic receivers. But when a piece of metal has minute electronic artifacts oscillating at the same frequency or a harmonic in near proximity of a signal generator (near = defined as a few inches to a few miles), a line in the air between the metal and signal generator becomes more detectable above the general electronic noise in the air. Thus, the term "signal line". So the theory is a small signal becomes more detectable above the noise levels when moving a detector along this line between the signal generator and metal. At least this is the theory I gather from what I read.
But this theory opens some questions:
1. According to Mike(Mont), the signal generator does not perform any metal discriminating. This is done biologically through human sensory and mental methods.
However, we see there are adjustments on the Vernell signal generators to select which kind of metal the signal generator is searching for.
Why does this adjustment exist if the electronic equipment does not physically discriminate metals?
2. We see a possible explanation to how the term "signal line" evolved. But is there any information that could explain what "forward gauss" is?
Can it be explained if we reject the Maxwell heaviside equations, or is it easily explained by conventional electronic theory?
Maybe it means the detection is done only on the forward side of the antenna, not the rear where the signal generator gets in the way...
3. From what we see in the Vernell Electronics locators that were studied and dissected by electronic engineers, they operate at VLF/ELF frequencies. Mike(Mont) thinks the Magnacast 5000 operates around 400 MHz, but can't be sure because his frequency counter does not go that high. A suggestion for Mike(Mont) is to connect a test probe between the antenna and ground, and check for frequencies between 10 and 10,000 Hz while switching through the 6 frequency adjustments on the Magnacast 5000. From what we know about the Vernell designs, this is where the frequency is likely to be found.
Best wishes,
J_P