A
Anonymous
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<span style="background-color:#ffff00;">It is an opinion that noise cancel is concerned with any electromagnetic induction of signals into the coil that are in the 50hz to 100khz range.</span>This includes any harmonics as well. While 60hz would be the more common in the US it would be electromagnetic induction from any source, power lines and transformers as examples that would be the primary problem. Ac motors are more of a problem if in the connected to an AC source when the noise, ripple, is not filtered. It would also be a problem inside of a building. In areas where there are commercial use of power then single phase, dual, and three phase would have to be considered and the harmonics.
If noises cancel shifts the spectrum in the lower frequency range up to 100khz then any induction into the receiver coil in this range would be a problem. It is simple to test an area for external noise. It can be done by using accept and edit features of the Explorer. One will see the noise on the screen and note that this can change dramatically within a very small distance from one point of reception to another. There are times when it is necessary to noise cancel in no less distance than 20 yards closer to power line but overhead and underground. For this reason I always noise cancel with each location and time I use the Explorer. Climatic conditions will also affect the need to noise cancel. Hot dry days compared to dam or humid air will have an affect on the induction of EMI. Some EMI can contain many frequencies such as a solar flare, lightning, electrical sparks from different sources, and radio transmitters.
<STRONG>This is one where I think we should noise cancel with each use and often if noise is suspected. It only takes about 30 seconds and can make a huge difference in locating faint targets that can be smothered by strong random external noise.</STRONG>
You might also consider that the Explorer has very high gain circuits. A sensitivity level of 28 is just below the point where internal noise is amplified enough to be heard. At 29 through 32 we have to take into consideration the internal noise and the external noise. I am not going to suggest if one should use Semi-auto Sensitivity or Manual although Minelab suggest Semi-auto for the above reasons. Very experienced users may well benefit using Manual in low mineralized soil where there is little external noise to deal with. The primary point is Semi-auto is designed to provide the best effective depth since the soil mineral change as do the amount of induced external noise.
If we turn our machine on and set the threshold and start to lower the coil towards the soil we will hear the detection and compensation for soil minerals. The closer to the soil we can lower the coil before we hear the compensation the less mineral there are. This is a fairly good measurement of soil minerals for our purposes and one I always use when searching a new area.
Have a great day,
HH, Cody
If noises cancel shifts the spectrum in the lower frequency range up to 100khz then any induction into the receiver coil in this range would be a problem. It is simple to test an area for external noise. It can be done by using accept and edit features of the Explorer. One will see the noise on the screen and note that this can change dramatically within a very small distance from one point of reception to another. There are times when it is necessary to noise cancel in no less distance than 20 yards closer to power line but overhead and underground. For this reason I always noise cancel with each location and time I use the Explorer. Climatic conditions will also affect the need to noise cancel. Hot dry days compared to dam or humid air will have an affect on the induction of EMI. Some EMI can contain many frequencies such as a solar flare, lightning, electrical sparks from different sources, and radio transmitters.
<STRONG>This is one where I think we should noise cancel with each use and often if noise is suspected. It only takes about 30 seconds and can make a huge difference in locating faint targets that can be smothered by strong random external noise.</STRONG>
You might also consider that the Explorer has very high gain circuits. A sensitivity level of 28 is just below the point where internal noise is amplified enough to be heard. At 29 through 32 we have to take into consideration the internal noise and the external noise. I am not going to suggest if one should use Semi-auto Sensitivity or Manual although Minelab suggest Semi-auto for the above reasons. Very experienced users may well benefit using Manual in low mineralized soil where there is little external noise to deal with. The primary point is Semi-auto is designed to provide the best effective depth since the soil mineral change as do the amount of induced external noise.
If we turn our machine on and set the threshold and start to lower the coil towards the soil we will hear the detection and compensation for soil minerals. The closer to the soil we can lower the coil before we hear the compensation the less mineral there are. This is a fairly good measurement of soil minerals for our purposes and one I always use when searching a new area.
Have a great day,
HH, Cody