Mike Hillis
Well-known member
The F5 Gain and Threshold are truly separated. So they do different things. Gain is an amplifier with 20 steps. Threshold is a signal gate with 10 steps (-9 to 0)
Regardless of Gain setting, a Threshold setting of 0 is a wide open detector. You control signal amplification with the Gain setting, You control the signal gate (how large a signal needs to be to be reported) with the Threshold. These two controls operated independantly of each other allow a lot of control over site conditions.
The Threshold has another setting range, +1 to +9 that amplifies the audio of the tiny signals let in by the 0 threshold setting. Actually all the signals are affected. The audio is more 'robust' with positive threshold settings. I find this additional audio rubustness of positive Threshold settings rather addicting so I always try to run with a positive Threshold setting. Just my personal preference.
There is another Threshold setting I call ++9. It is easy to find. You turn your Gain to Max. All the way to the dial stop. Then turn your Threshold to +9. The F5 should be chattering like crazy. Then take your threshold control, rotate it counter clockwise a quarter of a turn or so, then turn it clockwise just a tiny bit hard into the dial stop (the place where the dial stops moving) If you did it right, your chattering will stop or if not stopped completely, it will greatly diminish. If it didn't, try again. You can tell when you get into the ++9 setting because the detector will go stable or at least quit chattering. Mine always goes stable.
When you are in the ++9 Threshold setting, you get the benefits of Max Gain, the benefits of the positive Threshold audio settings, and the benefits of a stable detector. But you loose the Threshold gate setting of 0. It behaves more like a -2.
That is your coin setting you want to use unless you have a lot of surface trash and the Max Gain setting makes the coil foot print to large. If you need to reduce your coil foot print due to trash, or what ever, then take it out of ++9 and set up with more conservative Gain settings.
When hunting tiny targets, the tiny target are shallow. You don't want to mask the tiny targets with deeper trash targets so you use lower Gain settings and very high positive threshold settings. The low Gain settings manage your coil footprint, and the amplification of the underlying trash objects. The very high, positive threshold settings open the signal gate wide open to all the tiny signals, and add the audio amplification you want for those.
There is still a frequency limitation to how small a signal you can detect, but you would be amazed at how small you can go in target size with a small coil and high threshold settings. The F5 may not pick up the really fine chain links, but it will pick up and respond to the round links of the clasp and the clasp itself. Even the stock coil operates well for small gold this way.
Last thing before I have to run off. The F5 uses the ground signal to help mitgate EMI noise. Don't ask me how cause I dont know how, but it does. You can set up stable with the coil held still, or if your ground has any mineral content, you can setup with higher Gain and threshold settings with the coil in motion. A motion setup will give you stable operation while the coil is in motion but will chatter when the coil is help still or layed down when retrieving a target.
Hope that helps.
HH
Mike
Regardless of Gain setting, a Threshold setting of 0 is a wide open detector. You control signal amplification with the Gain setting, You control the signal gate (how large a signal needs to be to be reported) with the Threshold. These two controls operated independantly of each other allow a lot of control over site conditions.
The Threshold has another setting range, +1 to +9 that amplifies the audio of the tiny signals let in by the 0 threshold setting. Actually all the signals are affected. The audio is more 'robust' with positive threshold settings. I find this additional audio rubustness of positive Threshold settings rather addicting so I always try to run with a positive Threshold setting. Just my personal preference.
There is another Threshold setting I call ++9. It is easy to find. You turn your Gain to Max. All the way to the dial stop. Then turn your Threshold to +9. The F5 should be chattering like crazy. Then take your threshold control, rotate it counter clockwise a quarter of a turn or so, then turn it clockwise just a tiny bit hard into the dial stop (the place where the dial stops moving) If you did it right, your chattering will stop or if not stopped completely, it will greatly diminish. If it didn't, try again. You can tell when you get into the ++9 setting because the detector will go stable or at least quit chattering. Mine always goes stable.
When you are in the ++9 Threshold setting, you get the benefits of Max Gain, the benefits of the positive Threshold audio settings, and the benefits of a stable detector. But you loose the Threshold gate setting of 0. It behaves more like a -2.
That is your coin setting you want to use unless you have a lot of surface trash and the Max Gain setting makes the coil foot print to large. If you need to reduce your coil foot print due to trash, or what ever, then take it out of ++9 and set up with more conservative Gain settings.
When hunting tiny targets, the tiny target are shallow. You don't want to mask the tiny targets with deeper trash targets so you use lower Gain settings and very high positive threshold settings. The low Gain settings manage your coil footprint, and the amplification of the underlying trash objects. The very high, positive threshold settings open the signal gate wide open to all the tiny signals, and add the audio amplification you want for those.
There is still a frequency limitation to how small a signal you can detect, but you would be amazed at how small you can go in target size with a small coil and high threshold settings. The F5 may not pick up the really fine chain links, but it will pick up and respond to the round links of the clasp and the clasp itself. Even the stock coil operates well for small gold this way.
Last thing before I have to run off. The F5 uses the ground signal to help mitgate EMI noise. Don't ask me how cause I dont know how, but it does. You can set up stable with the coil held still, or if your ground has any mineral content, you can setup with higher Gain and threshold settings with the coil in motion. A motion setup will give you stable operation while the coil is in motion but will chatter when the coil is help still or layed down when retrieving a target.
Hope that helps.
HH
Mike