GPX 4500, erratic audible threshold with common settings.

G'Day all, I have not been a member long but would like for anyone to try answer my question. And hopefully answer anyone elses if I can.

I have owned and used my second hand 4500 for approx 6 months where I purchased from Reeds. I have watched JP's 4500 dvd SETA project many times.

My detector is set up to suit the Pilbara gold fields and have extracted the SETA Project settings along with help from other detector operators up here.

However my problem is if I try operate my detector in MEDIUM motion my audible threshold is "jittery" and apart from large obvious targets, any faint/deep targets are easily masked.

This only occurs when I try change my motion. It runs quiet in VERY SLOW motion. A detector operator mentioned he had to send his machine away to quiten and ramp his machine up.

Has anyone come across similar scenarios? As i wonder whether I have some settings which are interferring with each other but I keep telling myself they shouldn't as my settings are very similar to the SETA dvd's.

Any help is muchly appreciated.

Cheers.

crack-hardy,
Very difficult to determine your problem without listing all your settings?
First guess would be your gain & stabiliser are not set correctly.
Post your settings and we will have a better chance to help you.

Cheers
Peter

G'day,
I have been using the 4500 for about the same amount of time. Try running it in "slow" motion setting and fiddle with the gain and stab' settings. Some days you can run the gain at 14 and others you are scratching to get it over 11.

While the SETA video gives you a basic starting platform I don't think the settings shown are set in concrete. I have found that it really depends on the ground and the day as to which settings are more suitable. I have also found the coils behave differently. Again the setup in the SETA video seems to work for that particular machine with that particular coil in that particular location.

I have found yellow stuff from a poofteenth of a gram up to a few grams using the 4500 with the 11" Commander mono. I would be more than a bit hesitant to send the machine anywhere but minelab to have it checked out. It took a couple of months to work out how to set mine up on any given day and I think it will take a lot longer before I am confident that it is running and operating correctly.

This is probably as clear as mud, but all I can suggest is that if all else fails read the manual and fiddle from there.

G'day crack-hardy

I guess you are running the machine in "enhance", if this is the case then try the motion setting in "slow", RX gain in the range of 9 to 12 and the stabalizer in the range of 6 to 8, I find that the higher the RX gain then lower the stabalizer. Try the audio in "deep"

This range of settings work well with the Minelab 11" Commander mono coil.

Most days I can work my machine with a setting of, motion = slow, RX gain = 12, stabalizer = 6, audio = boost, this is with the ML 11" commander mono coil and external speaker system.

Set the threshold to just a steady hum, on my machine it's at about 11 O'clock position. Manual tune is mostly somewhere around 101 to 111 depends on the day and whether there are any other detectors around, just manual tune to a quiet spot or do a auto tune and see how that goes.

cheers dave

Nightjar wrote:crack-hardy,
Very difficult to determine your problem without listing all your settings?
First guess would be your gain & stabiliser are not set correctly.
Post your settings and we will have a better chance to help you.

Cheers
Peter

Nightjar,

My settings are-
Enhanced, VERY SLOW motion, RX GAIN 8-11, STABALISER 11, MEDIUM TRACKING, MAN TUNE 91-118, THRESHOLD 2 O'CLOCK, SEARCH MODE in G, FIXED GB.
I am running a NF MONO 14x9 eliptical.
The thing is I have found various size nuggets with it ranging from .5g up to ounce (though very shallow). However compared to other detectors my settings seem significantly different and I wander if I am at a disadvantage. Thanks for your reply

Yellow Hornet,

Not clear as mud, thanks for your help. I shall try varying it. Although I do try change settings I may need to try alot more variations.
cheers.

davsgold wrote:G'day crack-hardy

I guess you are running the machine in "enhance", if this is the case then try the motion setting in "slow", RX gain in the range of 9 to 12 and the stabalizer in the range of 6 to 8, I find that the higher the RX gain then lower the stabalizer. Try the audio in "deep"

This range of settings work well with the Minelab 11" Commander mono coil.

Most days I can work my machine with a setting of, motion = slow, RX gain = 12, stabalizer = 6, audio = boost, this is with the ML 11" commander mono coil and external speaker system.

Set the threshold to just a steady hum, on my machine it's at about 11 O'clock position. Manual tune is mostly somewhere around 101 to 111 depends on the day and whether there are any other detectors around, just manual tune to a quiet spot or do a auto tune and see how that goes.

cheers dave

G'Day Dave,
In reference to my reply to Nightjar my settings are visible. However if I try run with those settings and change into DEEP it just amplifies the jittering. However I will change to the new advised settings and Threshold changes and will let you all know how I go.
Appreciate your replies. Been very helpful. I will also post some pictures once I figure out how to.
Cheers.

crack-hardy wrote:My settings are-
Enhanced, VERY SLOW motion, RX GAIN 8-11, STABALISER 11, MEDIUM TRACKING, MAN TUNE 91-118, THRESHOLD 2 O'CLOCK, SEARCH MODE in G, FIXED GB.

G'day crack-hardy

Your settings that I see as to high, is the stabalizer at 11 and the threshold at 2 o'Clock, I would try the stabalizer at 6 or so and and see how that goes.

The stabalizer needs lower numbers to make the machine run more stable, if you want to run a high RX gain you need lower stabalizer numbers.

In the Minelab manual it says something like, make all your settings and then use the stabalizer to get a smooth and stable sounding machine.

cheers dave

Cheers Dave, sounds about right after reading the manual again.
I will let you all know my results. Much appreciated.


cheers

this is a vid i done on how to post pix

https://golddetecting.forumotion.net/t4882-easy-way-of-posting-pictures-on-the-forum

cheers
stoppsy

cheers stoppsy, will post some pics soon.

Crack-hardy just a quick question. You don't have any other electronic device on you at the time of detecting. The reason for me asking is, I too used to have that same problem with my 5000 and could not work it out. It didn't matter how many time I fiddled with the setting and re-tuned the wobble was still there. Found nuggets, but the wobble drove me stupid (no wize cracks fellows ) Anyway I found out that it was my Garrett Pin Pointer that I was carrying at the time that was courseing the problem. I was trying to tune that out all the time. It is now sitting in the car and no more problem. Detector runs as smooth as a Baby's bum

Wombat

Wombat wrote:Crack-hardy just a quick question. You don't have any other electronic device on you at the time of detecting. The reason for me asking is, I too used to have that same problem with my 5000 and could not work it out. It didn't matter how many time I fiddled with the setting and re-tuned the wobble was still there. Found nuggets, but the wobble drove me stupid (no wize cracks fellows ) Anyway I found out that it was my Garrett Pin Pointer that I was carrying at the time that was courseing the problem. I was trying to tune that out all the time. It is now sitting in the car and no more problem. Detector runs as smooth as a Baby's bum

Wombat

Similar problem with my 4500, but only with the M/L 11" mono, moved pointer from shoulder to bumbag, no interference now.

wombat/llanbric

I dont have a pin pointer, most I have on me is me head lamp. However I do have a tip which my friend solved with the garrett pin pointer. He simply wrapper the pointer in alfoil then holstered it on his hip and no more problem. He can wave it a foot away from the coil with the coil only picking up the alfoil. However I shall try all the above advice and fingers crossed.
Cheers

hey mate

I have been runing a 4500 in the pilbara for about a year aswell. i have noticed simmilar things to you, here is what i have learned

-Pilbara is bad for EMI I need to change tune settings quite often to find a quiet spot, some days can only run a small coil
-Pilbara ground is hot, I too often stuggle to run high gain and stabiliser settings JP recomends in SETA project
-I am a big beliver in setting your swing speed to what you are actually doing, running your machine in very slow means you need to swing very slow. I check over a test piece a few times a day to make sure i have it right. if covering alot of ground I normally run in medium to keep up with my swing speed , this results in a more "twitchy" threshold and have to back off on gain and stabiliser settings slightly, its a comprimise for working faster and covering more ground.
if im working a patch opposite applys slow swing speed right down, set to very slow which allows max gain and stab settings to get max grunt out of your 4500 to punch deep.
-some people on here feel that not all machines built equal I can not comment on this
-lastly ground ballance needs to be spot on, it took me quite a while to get the hang of it
-Daves comments and settings above are in very much the same range as mine

maybe for peice of mind get it checked out by minlab but chances are it is ok, you seem to have found more gold than me anyway

cheers Tom

G'Day Flying Kiwi.

Yeah it took me 18months of serious studying of areas, maps and plenty of walking around bush and just striked it lucky. But thanks for your reply. It gives me alot to look at and work with in reference to my 4500 problem. all I can do now is to trial and hopefully repay everyones help with some info...hopefully.
Might see you out there someday

Cheers.

Only problem I have found with the SETA DVD is the JP advocates running the threshold at 2 o'clock. In Victoria, (not sure about WA), 2 o'clock is WAY too high. I need to back it off to between 11 and 12 o'clock and like others have said, make your settings and then adjust your RX and finally your stabiliser. Its ok to say right today I am running my RX at 12, but you will find out very quickly if that's too high for the area/ground your on, because all you will do is dig ground noise. Like others have said always keep your stabiliser at between 2 and 4 below your RX.

If all else fails and it doesn't seem to matter what you do, it seems chattery just put the RX and Stabiliser back to FP, - ground balance and see how you go. Maybe a twitch or two from there.

Jon.

With my 4500 I found that when I want to tune it, I hold the shaft parallel to the ground and turn through 360 degrees noting which direction is the noisiest. I then hold the coil in this direction and do an auto tune. If necessary I then fine tune it around this reading. Works good for me.

Hi Toad,
You only need to do a 180° turn.
Place machine on the ground and then auto tune if this is your preferred method.


Peter

I run my threshold at at 2 oclock and that setting here in vic seems to suit my 4500. If I try to run it any lower ( 12 or 1 oclock ) it seems to get a little bit jittery regardless of my settings. But I suppose every machine seems to have its own personal settings that suit that unit. What works on mine is proberly not right for another 4500.
Cheers Steve.