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GPX 5000 Gain Question


Dakota Slim

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I'm up in NV with my GPX 5000 for the 1st time and have a question about gain. I am using an 18" Nugget Finder Advantage coil and If I set the gain high, I get noise as I swing the coil which is a bit annoying. I can lower the gain and the threshold will stay smooth.

My question is, if I lower the gain am I losing depth?

Any opinions or comments are welcome.

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What are your other settings? I ran the 18 in fine gold, and I left the gain in factory preset and it was stable and had good depth.

Dan

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Hi Slim,

From what I know smaller coils can handle more gain and larger coils generally don't like as much gain.

Don't think you will lose depth by running slightly less gain on a large coil.

As Dan says above, run somewhere around the factory preset and you should be good to go.

Some people are comfortable with a detector running slightly "ragged."

If that is something you can handle, mess with a higher gain and see how it goes.

If you get a good signal it might be interesting to play with the gain before you dig

and see what conclusions you come up with.

my 2 centavos

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Slim,

From another forum I remember Steve talking about the re-introduction of the 4500 and talking about the Fine Gold timing missing on that machine. He said that in many areas it is really not necessary to be in Fine Gold even tho some 5000 users would NEVER use any other timing. From this description I take it from Steve and others that there are some 'quirks' about this timing that you may not find in one of the other timings.

I still have my 5000 and I found my big nugget with it and the 18" Nugget Finder like you are using.

You may be able to stay as deep or even deeper in another setting and also not have any noise.

Have you been finding targets even with the noise?

Mitchel

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Thanks guys. For now I'll go with the gain setting that gives me a steady and smooth threshold and, as Flak suggested, maybe do some experimenting when I have a good target.

Doc, I tried various stabilizer settings but that didn't seem to help much. As you know, there are a million possible combinations with this machine and I am still very much a rookie with it. For what it's worth, let me add that this machine came with your screamer package but I am going with the standard setup and earphones until I get comfortable with it.

The bottom line is I could never get this 18" coil to run as smooth and quiet as I wanted with my GP Extreme and with a little experimenting I was able to do so with the 5000 so I am a happy beeper.

Now if I could only get this machine over a nugget...

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Slim

Im in a hot area...I run my gain at 9. Stab at 8. Seems to shut the hot rocks and black sand up a little

You just have to experiment and find out how to run it smooth, but not too smooth that its dumb.

Start low....keep bumping it up until its squawking at you...then go back a little.

Also...as you keep hunting that area you will start to hear whats a hot rock/minerals and ignore them

Go over the target a couple of time and if it fades away...its usually hot ground.

After digging a lot of hot rocks and black sand, you will see what I mean. :)

Just got to get yer ear tuned.

Hope this helps.

Tom H.

Edited by TomH
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x2 on Tom's response. I seem to get better depth when the gain and threshold were within a couple clicks of each other. I lost depth when they were spread out too far.

My way of doing testing was to bury a 1/2 gram piece about 4" depth and 1 gram piece at about 8" depth. I would do this in whatever type of ground I detect most in. Then with one coil, I would start at factory preset and start changing one variable at a time. Once you hear the signal, I add one inch of depth by adding one of my useless old college books on top of where my target was buried. :) Then I check it again and keep adding books until I find the max depth I can hear it. The advantage of this method is you can pretty quickly go through settings of your GPX without having to continuously dig up and rebury your targets. You get some of the ground effect without being a complete air test.

This was just my way of determining my best settings for my ground conditions. I am still very new to detecting but I just wanted to offer an idea for doing some experimentation on your own.

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Hi Andyy

I am guessing you mean "I seem to get better depth when the gain and (the Stabilizer) are within a couple of clicks…"

The other part of that…detecting through books is a novel approach but the ground where the target

is, and has been, buried for some time is best to test different settings imho.

best,

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Thanks for the catch FlakMagnet. I also agree with you about the ground. Just sharing methods.

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Hi Slim, Gain does not increase or decrease actual depth. Look at it like a CB radio, you have TX (power output) and RX (receive).... YOUR DETECTOR IS RX GAIN not TX so not putting out power and this is true VLF or PI detector. OK so what the gain does is allow you to set your 5000 to the best stable receive mode. To much gain will cause instability and loss of ability to clearly hear a target.

Turn your detector on and get it setup then turn the gain up a click at a time until it becomes unstable turn it back a click to regain stability and hunt. What # you are on will not matter.

You will have some tell you to turn it all the way up and hunt that way and not worry about it (know some that do) but you will miss deep targets especially large deep targets because your detector will be too unstable to recognize them. This is something I talk about at all my seminars to help folks understand the gain function as it is common for folks to mistake the word "gain" or "sensitivity" to mean more power output.

So the answer to your question is no you are not losing depth by making sure your RX GAIN is set to the most stable point, but you will lose depth by running an unstable detector.

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Thanks Bill. That makes a lot of sense and it is one good reason I am happy that I finally upgraded to the GPX 5000. I spent many hours using my GP Extreme when it wasn't stable -- especially with large coils -- and I have no doubt I left some detectable nuggets out there.

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Yes perhaps some were missed who knows :idunno: , but once you understand the gain function it makes an amazing difference. Often for us PI users the target may only slightly disturb your threshold letting you know there may be something there, just a whisper that makes you stop. With an detector even running slightly unstable it would be missed...

The key is understanding that there in no more power put out by running it higher simple truth and each coil will require it's own happy spot as once again we are setting an antenna to bring the best possible smooth signal to the receiver. :old:

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Nice explaination Bill…

Slim you are gonna just love this detector

especiallywhen you have it all tweeked out to your satisfaction

and then you hear a little wobble in the threshold.

You go "wait, what was that?"

When you sweep it again, the wobble is still there, maybe a little different sounding, hardly noticeable, but there.

You decide to dig it.

Show us your the first nugget you dig with a tiny shift in the threshold,

it's gonna be a beauty.

(in other words, good hunting)

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  • 2 weeks later...

Have to agree with Bill ... I was in the camp of turning the RXGain all the way up and then bringing it down to stable! Then I heard a talk with Kevin Hoagland a year or two ago ... he changed my view and made me do a bit of experimenting. Going from bottom of the scale up is definitely the way to go. My little test garden proved to me that I could hear more and better doing it this way. ... and the threshold is now smoother than ever and I usually have a really smooth threshold.

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  • 2 weeks later...

Bill's point is clear. And typically I understand you adjust gain with the stabilizer on FP. So once you set your Rx gain is there ever a reason to adjust the stabilizer setting from FP? Just trying to shorten the learning curve. Thx.

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