(This post was originally made by rcsnake but the link was lost)
HUNTING IN MINERALIZED GROUND WITH THE V3i
Rx Gain Sensitivity: will influence the all-metal mode, pinpoint mode and the discrimination mode. The setting for the Rx is determined by how much trash/iron is in the ground and the ground mineralization strength. The Rx gain being set too high can create problems with nails making them chirp and sound off like a good target. So reducing the gain at this type of site seems to help. Also, when the ground is really wet it seems to make the nails and iron targets sound off and chirp. The Rx gain and type of loop will react to the ground differently; this will also be true of bottle caps/iron.
All Metal Sensitivity: is for the all-metal and pinpoint modes and has no influence on the discrimination mode. This sensitivity will influence the mix mode operation. Usually I start out at 65 and go up as needed to get the desired sensitivity; having this set too low will make pinpointing a deep target harder and having it set high will make surface targets blare out and harder to pinpoint.
Disc Sensitivity: only applies to the discrimination modes. This sensitivity provides the most sensitivity to targets in the discrimination mode, therefore set it high as possible while keeping the detector stable as I usually run mine from 85 to 92. The VDI and Spectragraph on the display is also controlled by this setting so if using the detector in an all-metal mode the display reporting can be controlled by adjusting this setting.
TX Boost: will influence both all-metal/pinpoint modes and the discrimination modes for the instrument and will also have an influence on the ground mineralization. When used Tx Boost will reduce battery life of the instrument with the frequency of 2.5 kHz being the worse offender and 22.5 kHz being more efficient. Tx Boost also will help some in EMI areas, as the other sensitivities on the detector can be reduced which will reduce the influence of the EMI on the signals received.
Sensitivity Probe: The Sensitivity Probe was intended to give a suggested gain on the Rx Gain but it was inaccurate and set too low so when the V3i came out the suggested gain was take taken out. The idea was to keep the ground signal around 10% but this proved out to be to low. The signal it is measuring is coming off the preamp or the first stage so try to keep it around 20% and not approach the 100% as this will cause an overload. The can also measure noise level for the area and then it might give the user an idea if a frequency offset or even a different frequency is needed.
With that being said I usually do not use or look at this information as the information that I check is the ground probe and then make adjustments on the fly. As far as the Noise level goes if emi is a problem I just put the detector in the pinpoint mode and see if the audio is pulsating. If it is, I will use the frequency offset to find the least influenced set of frequencies or frequency. Most the time I just start hunting and make adjustments on the fly using the Live Control Bar.
S.A.T.: S.A.T. stands for Self Adjusting Threshold. S.A.T. can be used to help minimize or smooth out the ground noise in the all-metal modes, S.A.T. requires loop motion if you stop over a target, the target will disappear as the audio will return to the audio threshold. The SAT speed is for the all-metal mode and has no influence on the discrimination mode operations or pinpointing of targets. When hunting in all-metal or mixed mode I usually set this from 5 to 10. Lowering the number on the adjustment the longer it takes for the audio to return to threshold and the higher the number the quicker it will return to audio threshold. Having the S.A.T. set to deal with nasty ground is very useful when hunting for gold nuggets in mineralized ground, as a small nugget will be easier to hear if set correctly not too fast or too slow. The same can be said for targets while hunting for coins or relics in all-metal modes or mix modes with detector.
3-Frequency: Uses all three frequencies to report data and audio information. This selection will be the best on target data reliability. In mineralized ground this can be very useful as targets respond differently on signal strength at each of the different frequencies so there is a better probability of calculating the correct VDI of the target. It is not as sensitive as when using a single frequency but if turning the sensitivity up it can be almost as good. Single frequency 22.5 kHz will do better on small targets (gold chains) than the 3 frequency mode but the 22.5 kHz will also make the small foil sound better.
Best Data: Best Data is for three frequency mode and reports the VDI that comes from the strongest signal received and with the strongest frequency showing as the strongest Spectragraph VDI bar. The other two frequencies may or may not line up to the correct VDI bar with the strongest frequency bar. The audio will follow the strongest frequency received so it is possible for example to have the 22.5kHz respond as a good target while the other two frequencies (2.5kHz and 7.5kHz) will come in as a rejected VDI bar or even skewed on the spectragraph.
Correlate/Span Limit/Wrap: Correlate mode is for the three frequency mode and reports the VDI when two of the three frequencies agree on the VDI of the target. The span limits how far apart the VDI can be in order to report the VDI. The spectragraph will still show where the target is being reported at on that particular frequency and all the data that is being received not just correlated data. The correlate mode helps on iron chirps and seems to do better in the mineralized ground as the audio will give off a better
HUNTING IN MINERALIZED GROUND WITH THE V3i
Rx Gain Sensitivity: will influence the all-metal mode, pinpoint mode and the discrimination mode. The setting for the Rx is determined by how much trash/iron is in the ground and the ground mineralization strength. The Rx gain being set too high can create problems with nails making them chirp and sound off like a good target. So reducing the gain at this type of site seems to help. Also, when the ground is really wet it seems to make the nails and iron targets sound off and chirp. The Rx gain and type of loop will react to the ground differently; this will also be true of bottle caps/iron.
All Metal Sensitivity: is for the all-metal and pinpoint modes and has no influence on the discrimination mode. This sensitivity will influence the mix mode operation. Usually I start out at 65 and go up as needed to get the desired sensitivity; having this set too low will make pinpointing a deep target harder and having it set high will make surface targets blare out and harder to pinpoint.
Disc Sensitivity: only applies to the discrimination modes. This sensitivity provides the most sensitivity to targets in the discrimination mode, therefore set it high as possible while keeping the detector stable as I usually run mine from 85 to 92. The VDI and Spectragraph on the display is also controlled by this setting so if using the detector in an all-metal mode the display reporting can be controlled by adjusting this setting.
TX Boost: will influence both all-metal/pinpoint modes and the discrimination modes for the instrument and will also have an influence on the ground mineralization. When used Tx Boost will reduce battery life of the instrument with the frequency of 2.5 kHz being the worse offender and 22.5 kHz being more efficient. Tx Boost also will help some in EMI areas, as the other sensitivities on the detector can be reduced which will reduce the influence of the EMI on the signals received.
Sensitivity Probe: The Sensitivity Probe was intended to give a suggested gain on the Rx Gain but it was inaccurate and set too low so when the V3i came out the suggested gain was take taken out. The idea was to keep the ground signal around 10% but this proved out to be to low. The signal it is measuring is coming off the preamp or the first stage so try to keep it around 20% and not approach the 100% as this will cause an overload. The can also measure noise level for the area and then it might give the user an idea if a frequency offset or even a different frequency is needed.
With that being said I usually do not use or look at this information as the information that I check is the ground probe and then make adjustments on the fly. As far as the Noise level goes if emi is a problem I just put the detector in the pinpoint mode and see if the audio is pulsating. If it is, I will use the frequency offset to find the least influenced set of frequencies or frequency. Most the time I just start hunting and make adjustments on the fly using the Live Control Bar.
S.A.T.: S.A.T. stands for Self Adjusting Threshold. S.A.T. can be used to help minimize or smooth out the ground noise in the all-metal modes, S.A.T. requires loop motion if you stop over a target, the target will disappear as the audio will return to the audio threshold. The SAT speed is for the all-metal mode and has no influence on the discrimination mode operations or pinpointing of targets. When hunting in all-metal or mixed mode I usually set this from 5 to 10. Lowering the number on the adjustment the longer it takes for the audio to return to threshold and the higher the number the quicker it will return to audio threshold. Having the S.A.T. set to deal with nasty ground is very useful when hunting for gold nuggets in mineralized ground, as a small nugget will be easier to hear if set correctly not too fast or too slow. The same can be said for targets while hunting for coins or relics in all-metal modes or mix modes with detector.
3-Frequency: Uses all three frequencies to report data and audio information. This selection will be the best on target data reliability. In mineralized ground this can be very useful as targets respond differently on signal strength at each of the different frequencies so there is a better probability of calculating the correct VDI of the target. It is not as sensitive as when using a single frequency but if turning the sensitivity up it can be almost as good. Single frequency 22.5 kHz will do better on small targets (gold chains) than the 3 frequency mode but the 22.5 kHz will also make the small foil sound better.
Best Data: Best Data is for three frequency mode and reports the VDI that comes from the strongest signal received and with the strongest frequency showing as the strongest Spectragraph VDI bar. The other two frequencies may or may not line up to the correct VDI bar with the strongest frequency bar. The audio will follow the strongest frequency received so it is possible for example to have the 22.5kHz respond as a good target while the other two frequencies (2.5kHz and 7.5kHz) will come in as a rejected VDI bar or even skewed on the spectragraph.
Correlate/Span Limit/Wrap: Correlate mode is for the three frequency mode and reports the VDI when two of the three frequencies agree on the VDI of the target. The span limits how far apart the VDI can be in order to report the VDI. The spectragraph will still show where the target is being reported at on that particular frequency and all the data that is being received not just correlated data. The correlate mode helps on iron chirps and seems to do better in the mineralized ground as the audio will give off a better
