4500 timing questions

[DigDeep]

In my experience with my 4500 the EMI (electro-magnetic interference) is at its worst in Enhanced followed by Sens extra and smoothest threshold in Normal timings . This is in any type mineralization and every location I've been to in So Cal and the one time in Gold basin.

(To be clear, what I am talking about here is Not ground noise, EMI only)

One poster on another forum writes they get the smoothest EMI threshold in Enhanced mode, I get the total opposite results to EMI. Now I fully agree it's the smoothest timing for highly mineralized ground and hotrock laden dirt, but I usually have to turn down the RX/gain a bit or set it to Quiet if I am on any kind of slope or angled in anyway and sometimes when totally flat/level depending on the location I'm at .

Anyone have similar or different results concerning EMI and their timings.

DigDeep

[nuggethunting]

Hey DigDeep,

I get the best results for mineralized ground and EMI with the new Enhance timing. However, it varies from place to place. Here in Arizona we probably have some of the worst EMI interference and it's not getting any better with all the growth out West. I seem to get the most EMI Interference from Cellular/Communication Tower than Power Lines or Aircraft anymore.

In some of these locations where the EMI is bad I can't even hunt in Normal timing without lowering the Gain to under 10 & using Quiet Audio.

P.S. Did you send you GPX in for that recall they had?

Talk with you later,

Rob Allison

[DigDeep]

Yea I sent it in a while back.

It's fine, I can get it quiet without a problem. I was just curious if different 4500 are more susceptible to EMI in different timings.

Some guys say they get the least amount of EMI in Enhanced and some say it's least amount in Normal and some say it's least amount in Sen Extra.

Maybe it's the type of EMI.

[nuggethunting]

Hey DigDeep,

The EMI can vary by type and detector. However, one observation I noticed from a handful of guys that own GPX-4500's is the ones that sent them back in seemed to have more problems with the Enhance, while the guys that didn't send theirs in, had more problems in Normal. This might not be the case, just something I noticed from many people I've talked with. Frankly, I would probably rather have Normal timing run quiet than Enhance to get more outright depth.

I still haven't sent my GPX-4500 in. There are days when it runs super quiet, while other days it's much more noisier!

Take care,

Rob Allison

[donvp]

Hey DigDeep,

The EMI can vary by type and detector. However, one observation I noticed from a handful of guys that own GPX-4500's is the ones that sent them back in seemed to have more problems with the Enhance, while the guys that didn't send theirs in, had more problems in Normal. This might not be the case, just something I noticed from many people I've talked with. Frankly, I would probably rather have Normal timing run quiet than Enhance to get more outright depth.

I still haven't sent my GPX-4500 in. There are days when it runs super quiet, while other days it's much more noisier!

Take care,

Rob Allison

Mine is above the recall numbers. Runs very quiet in all settings after tuning. No issues.

[kiwinugget]

Mine is above the recall numbers. Runs very quiet in all settings after tuning. No issues.

What are the recall numbers ,ie , numbers after which we don't have to send them in ?.

[montana]

Digdeep. With the 4500 I have found that no matter what timings I use, If EMI is bad, I use the manual tuner rather than the auto tune. This can take a little time, but it is well worth it. Moving through the numbers a few clicks at a time , I can always find a quiet setting. Even one click can make a big difference. I do leave my audio in quiet all the time but compensate by running the target volume a little above factory preset. Even after 8 months or so I'm still experimenting all the time and I'm still coming up with new conclusions. One thing that slowly dawned on me was that changing from a small coil to a large one required some setting changes to achieve best performance. While I usually prefer special extra timings for small coils, I'm finding that with a 16" mono I'm using the normal timings more in certain ground types. Changing one factor may require changing others.----Bob

[nuggethunting]

Hey Bob,

Once again I have to agree with you. I guess we see "eye to eye" on a lot of things due to our experience with the Minelab's. This weekend I found my detector was running very quiet the first part of the day, but later the clouds came over and the unit started to make a little bit of noise. With a quick adjustment on the manual tuner I was able to elliminate it all.

The manual tune control is also great when you start hearing your friends sneaking up on you!

Take care,

Rob Allison

[Jonathan Porter]

Digdeep. With the 4500 I have found that no matter what timings I use, If EMI is bad, I use the manual tuner rather than the auto tune. This can take a little time, but it is well worth it. Moving through the numbers a few clicks at a time , I can always find a quiet setting. Even one click can make a big difference. I do leave my audio in quiet all the time but compensate by running the target volume a little above factory preset. Even after 8 months or so I'm still experimenting all the time and I'm still coming up with new conclusions. One thing that slowly dawned on me was that changing from a small coil to a large one required some setting changes to achieve best performance. While I usually prefer special extra timings for small coils, I'm finding that with a 16" mono I'm using the normal timings more in certain ground types. Changing one factor may require changing others.----Bob

Bob what sort of Gain levels do you use with the Quiet audio filter? I am curious how you are achieving a balance between Motion, Gain, Stabilizer and the Quiet filter, obviously by choosing to use Quiet but opting for Sensitive Xtra timings you are losing some performance to achieve a quite threshold, was just curious how far you go to get back the sensitivity.

JP

PS PM me if you consider the questions confidential, I know from experience that a lot of time and effort goes into finding this sort of stuff out and has a very real value in successful detecting terms.

[montana]

JP. That's a tough one, as it varies by the day, but I'll explain how I arrive at my settings. The best setting on the audio for killing interference is quiet. I combine that with the Very slow motion setting and this adds even more immunity to EMI. I feel that this is preferable to reducing the gain and stabilizer setting too far trying to achieve the same results. For instance if I run the audio in normal and the motion in slow I get too much interference with the gain at 8 and the stabilizer at 8. With either of these settings at 7 or below, performance seems to drop off dramaticly. So that puts me back to quiet audio and very slow motion and after turning the detector on and ground balancing, with gain at 10 and stabilizer at 10, I do a slow scroll through the manual tuner until I get a very smooth threshold. I might then move the stabilizer up a few notches to 12 or so. If I start getting a tiny bit of interference at that point I'll drop the gain to 9. I really don't pay much attention to the numbers , but rather let my ears guide my settings. With that starting point , I set the menu screen on manual tune as I detect and If interference starts creeping in I tweak the tuner to find a quieter number. Here again I pay no attention to the numbers and do this without even looking at the screen.

My use of the special extra settings is governed by the ground in my area. That is the timings that give the best overall results governed by average nugget size and depth and the average ground mineralization. Using small coils , I'm obviously not trying for huge depth, I'm trying for the nuggets that were drowned out by interference on previous machines and it turns out that there are lots of those. Now the fact that I can run a large coil which I rarely did with the GPs and SDs because of interference has put another dimension to the GPX, and I find that I can run the normal timings on most ground although I have to retune my ears to a slightly different threshold sound and a slight difference in the target response. I find my settings often come out about the same as if I was running in special extra. Putting on a large coil means that I am targeting deep nuggets so my thinking is that the normal timings are a better option than the Extra timings in that case. With the relatively mild ground in my area I'm targeting nuggets that were hidden by a ratty threshold rather than nuggets that were masked by hot ground which may be the opposite in some areas. For new patch hunting , settings become less important as there will be some sitting ducks that factory presets are fine for. Pounding old patches rquires doing something that others haven't done.----Bob

[FlakMagnet]

Interesting and smart - as always Bob.

Flak

[Jonathan Porter]

Very interesting and confirms some of my thoughts on the matter, my suggestion would be to retain as much Motion speed as possible before going past the FP Gain setting of 8 but otherwise what you are doing makes perfect sense (eg: maybe run a Gain lower than 8 to justify a Motion setting of Slow and a Stabilizer setting of 10, the reason I suggest a lower Gain is due to the reduction in depth due to the Quiet audio settings but feel a lower Gain will not impact too much on overall sensitivity so long as the faster Motion setting and higher Stabilizer setting is used). Bob have you tried the GB OFF feature in combination with your methodology? Seeing how it is interference you are mainly having to deal with and not so much the ground, it would be interesting to see how GB OFF in combination with your techniques behaved? Another thought would also be the SHARP timings, obviously you would have to tweak the settings to suit but maybe as a second option to the Normal timings?

I have friends over here who swear by the Threshold OFF in combination with SHARP timings and Full Gain technique for deep little nuggets in quiet ground, not sure how this would go with interference though. Out of interest the interference you are talking about is it a slow steady oscillation or a rapid crescendo type behavior or a combination of both?

One thing is for certain, the GPX-4500 really does offer a plethora of options for users world wide so they can personally adjust the machine to suit their particular terrain and detecting style.

JP

[DigDeep]

Well it's cool to see my old thread get fired up again.

DigDeep

[montana]

JP. I hear both types of EMI, frequent sharp spikes, and steady oscillations at times. The oscillations can usually be tuned out easily with the manual tuner, the sharp spikes are a different story, and it's the sharp spikes that make the threshold off/ high gain trick very annoying to me and I have decided not to explore it further. I can't seem to be able to make the GB off feature work well either. There seems to be just enough mineralization where I've tried it to make it a little difficult. As far as the sharp timings, I'm still experimenting with that and no opinion yet.

With the quiet audio and very slow motion setting , I've found that I only lose noticable depth and sensitivity if I swing TOO FAST and in that case I can make a target totally disappear and I think that is how I make the Quiet audio/ Very slow motion thing work for me. When I know I'm on gold my sweep is at a snails pace. There is also a very different audio response with these settings, that is it knocks the peak off the signal and broadens it and I've learned to quickly recognize this altered response which some may call a loss of sensitivity if they are used to the higher peak that is achieved with the faster motion settings and more aggressive audio settings. Now some may find that this flatter response is similar to a ground noise and it is, which I offset by constantly updating the ground balance, and I almost always re-balance and check a target again before digging it. Keep in mind that I don't ever want to listen to a wobbly threshold again and I'm willing to miss an occasional target if that's what it takes, but I don't think I miss an awful lot. Some of my detecting buddies use the more aggressive settings very succesfully because they feel they can move faster and cover more ground. I've always said that there are basicly 2 ways to detect with both working well . That is either go slow and cover the ground carefully, or go 4 or 5 times faster and cover 4or5 times more ground. My settings work well for the first style , but different settings would work better for the latter and the EMI isn't a big issue for some folks. My settings would definately not be for the guy who wants to cover a lot of ground quickly, although it works fine for new patch hunting that has never seen a detector where there are almost always sitting ducks that would be gotten with any reasonable settings. Everything has to be put into context. Am I hunting previously detected ground? Has it been hammered, or just detected casually a couple of times? Am I the only one who has detected it before? How sloppily or carefully did I do it the first go round? I always feel and rightly so that I just went for the sitting ducks the first go round. Once they are gone I can return at my leisure and get the tough ones. I can make a patch last for days this way if I know nobody is likely to stumble on it and if they do , with the ducks gone they may not get much anyway unless they are savvy enough to realize that it was sloppily done and they take time to do it right.

At any rate, as you say JP the 4500 lets me do it my way and others can do it their way. We didn't have much choice before the GPX series. My only real advice as far as settings is to forget about finding a magic set of do all settings and learn the detector well enough that you are doing what it tells you to do and it is doing what you want it to do. Some have this sort of relationship with their computers . I find the detectors much easier to deal with.----Bob

[Jonathan Porter]

Interesting remarks Bob and much appreciated I am sure by others who read these threads. On another note have you experimented with the Signal control at all? I have found a lower setting works better with lower Tone settings etc, it might also be interesting to see what works for you with the slower Motion settings from an experimentation point of view. Your thoughts?

JP

[montana]

JP. As always I will try anything you suggest and must admit that I've neglected to play around with the signal settings . When I stated that I get a flatter signal response using the very slow motion and Quiet audio settings, I was referring only to the targets that are close to the maximum depth capabilities of the detector and coil and I think at this point there is some flattening of the signal in all settings, but a little more so while using my settings. I know from experimenting that once one of these "soft" targets is located , I can switch to a faster motion setting and stronger audio setting and the signal peak is of a much higher nature. I find however that even though I get a better signal response on a known good target , I also get more ground response, response to hotrocks, and EMI problems making it more difficult for me to pick out the stronger good target response as I move along. I've probably gone a little farther than most people would to eliminate unwanted noise, but the moment I change to a faster motion setting or a stronger audio setting , I'm not happy with what I'm hearing even though I know for a fact that I've lost the ability to pick out some of the tiniest nuggets in the .1 gram range but know that I could get them with the 4500 if I chose to set it as noisy as the GP series always ran with no option to to do anything about the noise. I'll gladly sacrifice a few of these to have a more pleasant detecting experience-----Bob

[Jonathan Porter]

Bob, the higher the Signal peak numbers the tighter the response assuming you are running above 50 on the tone levels. Lower tones tend to sound better with a lower Signal control number, but because you are running a Very Slow Motion setting there could very well be a magical number in the Signal control train that is the sweet spot for you.

As an aside next time you are experimenting with GB OFF, try using Enhance with a very high Gain setting along with your Quiet audio filter, I was surprised with some of the VERY small gold I was finding using a Commander 8" Mono in quiet ground types. Enhance has a lot more sensitivity than people give it credit for but because of the perceived signal loudness reduction when directly cross compared to Normal or Xtra timings it is avoided (fair enough too), however with GB OFF the Enhance timings help tame the ground whilst maintaining an almost VLF type response in the 4500.

JP

PS I understand your methodology behind the removal of EMI, the older I get the less patience I have for it as well, going by your results you are not compromising much in the way of performance.

[montana]

JP. I run my tone in the mid 60s , so I'll definately play around with the signal peak settings. I'll also try the GB off/ Enhanced trick on some crumb spots. The possible setting combinations along with the array of coils available is mind boggling.----Bob

[donvp]

Recalled 4500s are serial numbers below 1200 (I believe). I have a 16" round mono NF coil that runs absolutely dead quiet at default factoy settings. Great place to start experimenting for more depth & senitivity. Best detector I ever had.

[montana]

JP. I tried increasing the signal peak setting. I had it set on 17 and moved it up to 20. I got 2 nuggets I'd missed before, but not sure if that was why because the terrain could have been a factor. It certainly didn't cause any problems and I'll leave it there for a while. Tomorrow I'm visiting a dink patch and I'll try the enhanced timing with GB off, high gain and the little Commander. The ground is a little tricky so it will be a good test. I know there are still some tiny ones there. Thanks for throwing some new ideas out there. We all need to keep trying new things . Once we find some settings that work well , I think we all get in somewhat of a rut, and I don't think anyone has thoroughly explored all the possibilities with the 4500. I hope Minelab keeps the 4500 for at least another year before coming out with a new one. I'd like to have that much time before being tempted to upgrade. It takes a lot of time to really get used to some new settings and to really give them a good try. In most cases I like to give new ideas several days at least before drawing any conclusions.----Bob

[FlakMagnet]

Bob,

you can imagine how behind the curve it makes those of us who

are not able to get out and have time on the ground to work with the

settings these threads talk about.

Thank both you and JP for you informative, candid and well thought-out

discussion.

(now where did I put my note pad...)

Flak

[grubstake]

Speaking of timing, I wish I had the gold to get me one of those new 4500 clocks. Ha! Ha! Grubstake

i HAVE TO GO TO fRESNO TODAY, TO MY HEART dr. aNYONE WANT TO VOLINTEER TO TAKE MY PLACE AND DRIVE THE 210 MILE ROUND TRIP FOR ME? no?

[montana]

Grubstake. Speaking of timings I hope your "ticker" is doing okay.---Bob

[montana]

Flak. Thanks to the internet you aren't out of the loop and can benefit from others experiments. These forums cut the learning curve almost as much as getting out there more often. I know some detectorists who have never checked out any of the forums and I think they are doing themselves a disservice whether they participate in the discussions or not. There's a ton of info that they can't get anywhere else.----Bob

[grubstake]

No Montana, heart is getting worse everyday. I don't know how long I got left, not much more they can do for me, DR. said I'd be damned lucky if I make it a couple of more years. Congestive heart failure, sometimes I swell up like a ballon, but as long as I can walk, I'll be detecting. I don't think I have an expiration date stamped on me anywhere. I'm just going to live my life like always, if I drop dead detecting, then everyone will know I went happy. Better than sitting at home waiting for it to come, Life is ment to live. I reget nothing, done things most only dream of, found pounds of gold, traveled the world, been in ever state there is. Have a loving wife. got a roof over my head, and haven't gone hungry yet. What more could you ask for, not to mention the 100's of friends I have. Life is great. But when I go, I'm being cremated, no services, my ashes are going to be dumped off the bagby bridge, a place I truely love. I'm here until I'm not. thats all anyone can say. Grubstake