I had mentioned in a post that I had compiled bits of information and such from different posts about the F5, mainly from Mike Hillis, and saved them in a notepad file so I could quickly reference them when I needed them without having to go back and search through different posts to find what I needed. Someone asked me to send this to them, but instead I figured I may as well just post it. I hope my little bit of hunting and picking out bits of information may be of help to someone. Of course Mike is really the one to thank, i'm just trying to condense it down so it could referenced quickly. Btw, Mike if you'd rather I not have this posted, just let me know and i'll get rid of it! 
It is mostly all your information afterall. 
Learning the F5:
****"The gain is basically the power, a magnifier of the signals that increases or decreases the strength of those signals.
The threshold controls what size signal the detector will pick up.
Anything below 0 with the threshold and the detector is restricting smaller signals from being detected to some degree.
At 0 the threshold is totally open, above 0 threshold settings will increase the volume of all signals.
Mike H. made an analogy a while back that stuck with me. The threshold is the door that controls what signals get in. At 0 the door is wide open. Below 0 the door is partly shut. Above 0 threshold does not open the door more, it merely increases the volume.
A higher threshold is usually preferred when you're looking for very small targets, small gold for instance.
Stability aside go with what you can tolerate re: the amount of valid signals coming through which will vary depending on the site conditions (trash ect.). In areas with a lot of small trash you can go with a lower threshold to reduce signals from the tiny stuf and then perhaps up the gain a bit. Of course you could just notch out the foil range for coin hunting but many prefer to hear it all.
Lower threshold settings should not cause much if any loss/depth on coin sized targets however the signal will be audibly weaker."
****Some help with your TID....pinpoint the target inside the golf ball size opening in front of the lower rod, then sweep for id. When you look at your TID, also look at the confidence graph. The more confidence bars lit up, the stronger and better the read. Disregard the lower graph readings and just keep the higher graph readings. . If you sweep 4 times and get a 20/4bar, 33/3bar, a 22/4bar, and a 70/2bar, keep the 4 bar readings and ignore the others. This scenario would give you a 20 and 22 reading.....Your intial pinpoint will tell you what to expect to see, confidence bar-wise.
****The Phase number changes every second. Ignore it unless you are pumping your coil. When you want to check your ground balance, just pump the coil over clean ground and see if the phase number and ground numbers are still the same or close to the same. If you see the numbers have become more than 3 or 4 numbers apart, reground balance by pressing the phase lock button and pumping the coil over the ground again. Then ignore the Phase number until you are ready to check your balance again.
****Set your Gain and Threshold so that your detector is stable. You only want it to beep when you are over a metal target. If you have it set to hot you will get a lot of false signals. Set your Gain to somewhere between 65 and 85, and then raise the Threshold up until it starts to chatter, then back it off until it stops chattering. Now it will only beep when you are over or around metal.
****Set your discrimination low (around 8 or 9) unless there are so many targets that you can't focus. In that case, raise the discrimination until you can handle (read "process") the audio. Use a tone id option that you are comfortable with.
****Only recover the repeatable signals. They repeat on both left/right sweeps over the target.
****You never know about the weak signals. They could be fringe depth targets or they could be micro trash or they could be oxidized iron that got charged up enough to spike a reading. Raising the Gain like you are doing is good, if you investigate them you want to try to get the best signal response you can. You can also try raising the threshold closer to +9 to get a more definitive (sharper) audio response. Typically, if it doesn't pinpoint, or can't pinpoint in one specific location it is trash.
Speaking of fringe depth targets (objects at the limit of the detectors ability to detect them with the current settings), Threshold settings play a big part of how they will sound. Theshold settings closer to 0 will give a "whisper" type response. Threshold settings closer to the ends, either -9 or +9 will give more "ping" type responses. I bring this up so you know what type of audio to expect for the deep objects.
****The can slaw is jumping up into the high numbers because your not centered over the target. To get the most accurate TID, pinpoint it to the center of your coil and resweep. The numbers will drop back down where they belong.
**** Normal basic jewelry settings are:'
Threshold - a high positive setting, all the time. I like +5.
Gain - raised until it starts to chatter, then reduced until stable. Gound minerals determine if I do this with the coil held still or with the coil in motion.
Tones - most of the time I use the 4 tone mode but it really depends on what I'm focused on hunting.
Discrimination - I usually run around 7 or 8. Unless I'm focused into a particular range of targets in which case I'll use the notches to limit the audio as much as possible to just that range.
****There is a point where the threshold setting stops giving you a depth increase and changes over to a modification of target response. Threshold settings close to 0 make fringe depth targets sound as "whispers". When the threshold is moved out toward the edges (-9 or +9) then the fringe depth targets start to sound more like faint "ticks". Since it is often difficult to get a +9 threshold setting in urban environments it is not general knowledge, and I may be the only person that hunts with a -9 threshold setting on a regular basis and aware of the differences. In fact, although I prefer the audio rubustness that positive threshold setting give, at sites where my ground minerals are low enough, I like coin hunting with very low (-9 to -5) threshold settings and very high gain settings. For gold jewelry hunting I use very high (+5 or higher) threshold settings with stable gain settings.
****You will also find that you can put the F5 into 2-tone mode and walking parallel to them, drag the tip along foundations and listen for the zip sounds among the reinforcing iron and pick up targets that nobody else can.
****if you are getting chatter with the coil held still, that is EMI. Drop your threshold another number.
****if you are getting chatter with the coil in motion, that is ground noise, trash and such. Verify your ground balance, and if the trash is too much, notch some of it out.
Pinpointing:
****1st, for shallow targets, stay in Disc mode and use the toe of the coil to pinpoint. Just wiggle the coil back and forth over the target while you move the coil back toward you until you lose the target, then move slightly back. Youll get it just under the tip. Practice it a bit and youll get good at.
****2nd. For deeper objects or if you have trouble pinpointing with the toe of the coil, Press pinpoint and pinpoint the target based upon the best audio, then release and repress the pinpoint button again, and pinpoint the target again. This is called detuning. What happens is that when you pinpoint the target, then release and press the pinpoint button again while over the target, you have detuned the target response, which has made the target response smaller. Because the target response is smaller, you can get your coil better centered over it. You might even have to actually press the coil to the ground like you were trying to mash the target to pick it up again. You can get a very tight pinpoint using the detune process. Again, practice makes you better.
****I see posts about jumpy target ids. The coil design will give jumpy id's for the deeper objects unless you get it pinpointed to the sweet spot of the coil. Use a golf ball to find the sweet spot on the coil by placing it in on the inner loop. Roll it a bit and then let it come to rest. That is the sweet spot on the coil. Mark it, memorize it, something. That golf ball size area is the coil's most sensitive spot. When you get jumpy targets, pinpoint, detune and pinpoint and detune again if needed to get the target centered in that spot. Then sweep it. Many times the id will stabilize enough for better decisions. Watch the confidence bar. Works well on iron falses as well.
It is mostly all your information afterall. Learning the F5:
****"The gain is basically the power, a magnifier of the signals that increases or decreases the strength of those signals.
The threshold controls what size signal the detector will pick up.
Anything below 0 with the threshold and the detector is restricting smaller signals from being detected to some degree.
At 0 the threshold is totally open, above 0 threshold settings will increase the volume of all signals.
Mike H. made an analogy a while back that stuck with me. The threshold is the door that controls what signals get in. At 0 the door is wide open. Below 0 the door is partly shut. Above 0 threshold does not open the door more, it merely increases the volume.
A higher threshold is usually preferred when you're looking for very small targets, small gold for instance.
Stability aside go with what you can tolerate re: the amount of valid signals coming through which will vary depending on the site conditions (trash ect.). In areas with a lot of small trash you can go with a lower threshold to reduce signals from the tiny stuf and then perhaps up the gain a bit. Of course you could just notch out the foil range for coin hunting but many prefer to hear it all.
Lower threshold settings should not cause much if any loss/depth on coin sized targets however the signal will be audibly weaker."
****Some help with your TID....pinpoint the target inside the golf ball size opening in front of the lower rod, then sweep for id. When you look at your TID, also look at the confidence graph. The more confidence bars lit up, the stronger and better the read. Disregard the lower graph readings and just keep the higher graph readings. . If you sweep 4 times and get a 20/4bar, 33/3bar, a 22/4bar, and a 70/2bar, keep the 4 bar readings and ignore the others. This scenario would give you a 20 and 22 reading.....Your intial pinpoint will tell you what to expect to see, confidence bar-wise.
****The Phase number changes every second. Ignore it unless you are pumping your coil. When you want to check your ground balance, just pump the coil over clean ground and see if the phase number and ground numbers are still the same or close to the same. If you see the numbers have become more than 3 or 4 numbers apart, reground balance by pressing the phase lock button and pumping the coil over the ground again. Then ignore the Phase number until you are ready to check your balance again.
****Set your Gain and Threshold so that your detector is stable. You only want it to beep when you are over a metal target. If you have it set to hot you will get a lot of false signals. Set your Gain to somewhere between 65 and 85, and then raise the Threshold up until it starts to chatter, then back it off until it stops chattering. Now it will only beep when you are over or around metal.
****Set your discrimination low (around 8 or 9) unless there are so many targets that you can't focus. In that case, raise the discrimination until you can handle (read "process") the audio. Use a tone id option that you are comfortable with.
****Only recover the repeatable signals. They repeat on both left/right sweeps over the target.
****You never know about the weak signals. They could be fringe depth targets or they could be micro trash or they could be oxidized iron that got charged up enough to spike a reading. Raising the Gain like you are doing is good, if you investigate them you want to try to get the best signal response you can. You can also try raising the threshold closer to +9 to get a more definitive (sharper) audio response. Typically, if it doesn't pinpoint, or can't pinpoint in one specific location it is trash.
Speaking of fringe depth targets (objects at the limit of the detectors ability to detect them with the current settings), Threshold settings play a big part of how they will sound. Theshold settings closer to 0 will give a "whisper" type response. Threshold settings closer to the ends, either -9 or +9 will give more "ping" type responses. I bring this up so you know what type of audio to expect for the deep objects.
****The can slaw is jumping up into the high numbers because your not centered over the target. To get the most accurate TID, pinpoint it to the center of your coil and resweep. The numbers will drop back down where they belong.
**** Normal basic jewelry settings are:'
Threshold - a high positive setting, all the time. I like +5.
Gain - raised until it starts to chatter, then reduced until stable. Gound minerals determine if I do this with the coil held still or with the coil in motion.
Tones - most of the time I use the 4 tone mode but it really depends on what I'm focused on hunting.
Discrimination - I usually run around 7 or 8. Unless I'm focused into a particular range of targets in which case I'll use the notches to limit the audio as much as possible to just that range.
****There is a point where the threshold setting stops giving you a depth increase and changes over to a modification of target response. Threshold settings close to 0 make fringe depth targets sound as "whispers". When the threshold is moved out toward the edges (-9 or +9) then the fringe depth targets start to sound more like faint "ticks". Since it is often difficult to get a +9 threshold setting in urban environments it is not general knowledge, and I may be the only person that hunts with a -9 threshold setting on a regular basis and aware of the differences. In fact, although I prefer the audio rubustness that positive threshold setting give, at sites where my ground minerals are low enough, I like coin hunting with very low (-9 to -5) threshold settings and very high gain settings. For gold jewelry hunting I use very high (+5 or higher) threshold settings with stable gain settings.
****You will also find that you can put the F5 into 2-tone mode and walking parallel to them, drag the tip along foundations and listen for the zip sounds among the reinforcing iron and pick up targets that nobody else can.
****if you are getting chatter with the coil held still, that is EMI. Drop your threshold another number.
****if you are getting chatter with the coil in motion, that is ground noise, trash and such. Verify your ground balance, and if the trash is too much, notch some of it out.
Pinpointing:
****1st, for shallow targets, stay in Disc mode and use the toe of the coil to pinpoint. Just wiggle the coil back and forth over the target while you move the coil back toward you until you lose the target, then move slightly back. Youll get it just under the tip. Practice it a bit and youll get good at.
****2nd. For deeper objects or if you have trouble pinpointing with the toe of the coil, Press pinpoint and pinpoint the target based upon the best audio, then release and repress the pinpoint button again, and pinpoint the target again. This is called detuning. What happens is that when you pinpoint the target, then release and press the pinpoint button again while over the target, you have detuned the target response, which has made the target response smaller. Because the target response is smaller, you can get your coil better centered over it. You might even have to actually press the coil to the ground like you were trying to mash the target to pick it up again. You can get a very tight pinpoint using the detune process. Again, practice makes you better.
****I see posts about jumpy target ids. The coil design will give jumpy id's for the deeper objects unless you get it pinpointed to the sweet spot of the coil. Use a golf ball to find the sweet spot on the coil by placing it in on the inner loop. Roll it a bit and then let it come to rest. That is the sweet spot on the coil. Mark it, memorize it, something. That golf ball size area is the coil's most sensitive spot. When you get jumpy targets, pinpoint, detune and pinpoint and detune again if needed to get the target centered in that spot. Then sweep it. Many times the id will stabilize enough for better decisions. Watch the confidence bar. Works well on iron falses as well.