Tuning your 4500

Hello members,
How many 4500 owners always use "Auto tune" as opposed to manual tuning?


Cheers
Peter

Hi Peter ,

I never use auto tune - my 45`s happy number is 96 ...
Although i do manually tune it when the EMI is frantic between the range of 80 - 110 .
Cheers
gully hunter

Hi Nightjar,

Mostly manual for me, but will auto tune on the odd occasion just for curiosity.

Cheers
A

ARARAT wrote:Hi Nightjar,

Mostly manual for me, but will auto tune on the odd occasion just for curiosity.

Cheers
A

I'm the same as ARARAT on this one. I find that 110 or 111 is good mostly and when the Mrs is detecting near we can detect fairly close (about 20m) apart. Sometimes with other peoples machines I need to use 101 or 102 to get some stability.

On a bad EMI day I will hit the auto tune and watch the screen and listen and you will see and hear quiet and noisy sets of numbers fly past.

cheers dave

I hardly use Auto Tune.
I manual tune somewhere in the range of 80 - 120.
Sometimes just for fun I will run Auto Tune to see if it comes close
to where I set it in Manual... it hardly ever does.

As Dave said its only useful for a quick scan to see if theres a quieter section but its prettymuch useless here on both the 4500 and 5000.The scanning is too quick to get accurate sampling as often the interference is erratic.
Steve

Here's my version, and it may not be correct.
The auto tune function searches for a quiet set of frequencies, it does this very rapidly, much faster and more accurate then a human can....this was its design.

How do you the human know, that your not tuning it closer to the source of the interference.??
EMI is not per minute, its per second.......its ever changing and waits for no man or machine to listen for a better set of operating frequencies.
Hit the auto tune and note where it stops...do it again and did it stop on the exact same number???..... not likely.


So manual tune vs auto tune.......just as either thinks its found the quietest freq......the EMI changes again.....it may change for the better...it might not.??

I now just hit the auto tune and get on with the job....adjusting it now and then if others are near by, and hit the auto tune a few times a day just for good measure when i feel the need stop and roll a fag.

Another spanner in the works is........low freq better depth...high freq better sensitivity....small coil better sensitivity....big coil better depth.....now do the maths and toss in more windings on the elip coils, add more EMI for good measure as they are more sensitive than similar sized round.

I pretty much agree with you narrawa. I hit the auto tune and then I might make small adjustments to compensate for other anomilies. Like when the ground dictates that I have to punch a bit deeper or if I"m chasing small shallow bits. But even then They are only minor adjustments. As the other settings on the 4500
can dictate what you want to achieve.

Yep,me too

Narawa ,
I use a 4000 but always use auto tune . I turn the gain up to 15 whilst auto tuning.
I swing mainly in the golden triangle and find the auto tune usually settles on a frequency over 200.
I figure this suits the small stuff which is generally what I find.

Staples

I turn the gain up to 15 whilst auto tuning.

I give newbies this info when training them, i leave it up to them as to whether they want to employ it or not.
I myself go more on the fact that EMI is ever changing so chose not to employ it.

With the auto tune, i dont know how precise its function really is, i just go off what its design to do.

even though i have a 5000, the only time i ever auto tune is when i'm detecting with someone in close range to me. once autotuned, i adjust the tune manually to find the most stable setting.

I've used both auto and manual tune on the 4000,4500and the 5000. I yet to decide which is better.

Wouldn't it be great if the machine did it fully automatically so we didn't need to stop and fiddle around?

Who decided that 90-110 was the optimum range? Was it JP?

Robert

Another spanner in the works.
I know several who swear by auto tune then crank the gain up to 15 then wind down the threshold until it running silent. They claim the positive target signals still ring through clear without the emi chatter?
Tried it once but soon went back to running a faint threshold with the gain adjusted for best results on the given ground.

Peter

Another spanner in the works is........low freq better depth...high freq better sensitivity....

I usually use Manual tune somewhere between 80 -110 til the detector goes silent. I would like to know thou if the above statement has any merit. If I use 80 instead of 110 does that actuall give me better depth with a bigger coil on?

Gday Peter and All
I use the Auto a fair bit, especially when changing search areas. I do the 360 or 180 degree spin, get the noisiest area, switch the Motion setting to fast then press the Auto Tune and then reset the motion after tuning. Makes the detector very noisy during the tune process but helps the machine select the quietest channel I think.
Generally in the Murchison/East Murchison I find the selection ends up around the 130-140 mark but sometimes out of the blue it throws in a 200+. Who Knows?
cheers
Brett

I would like to know thou if the above statement has any merit. If I use 80 instead of 110 does that actuall give me better depth with a bigger coil on?

I doubt that small a swing would be measurable out in the field.
Not sure but i think the freq swing on the tune function is only very small.???

Me thinks if there is an optimum setting, it would have to be 127-128. Which is the center....but!! EMI may be more active in the range of numbers you chose when overriding the auto tunes decision.???

Or you could look at it like i use to, and that is.
Large coils by design go deeper, and loose some sensitivity on the way.....so why not use high tune numbers to up the sensitivity a tad.? Reverse for small coils which by design are more sensitive, but lack some depth.
If there is anything in the freq adjustment debate, low numbers vs high numbers, than this would have merit yeah.?

[/quote]Large coils by design go deeper, and loose some sensitivity on the way.....so why not use high tune numbers to up the sensitivity a tad.? Reverse for small coils which by design are more sensitive, but lack some depth.[quote]


You have a good point there Narrawa, never thought of it that way.

A matter for thought. We were shown this method for tuning a 4500 by professional detectors in WA. I presume would work same in victoria.
Instead of holding your coil up in the air, lay your coil on the ground and tune into the ground. (as if detecting, but lay it there still) We do this all the time now and seems to find quietest setting to detect. Cannot tune in manually any better.
Try it, you will be amased.
travelergold

Gday Traveller
I have always tuned my detector on the ground but I have the coil in a vertical position. Do I understand you that you have the coil in a horizontal position on the ground? Never tried that and I was under the impression that the tune was to get the best atmospherics for the detector and the Ground Balance, Gain etc was for tuning ground parameters?
cheers
Brett

Hi Brett, Yes we have the coil horizontal to the ground, ie flat on the ground. It detects what is in the ground, not the air. The chaps that gave us this little trick said " you are detecting the ground, get the quietest from the ground, not the air." We have found it has always been excellent for us in the west anyway, have not tried in in the golden triangle.

Thanks traveller, I'll give it a shot next time out to see if it makes any difference.
cheers
Brett

The guy who ran the minelab training days in Vic. and lives in Talbot also suggested this method of laying the coil flat on the ground when auto tuning. (see i was listening) I'm curious why my 4000 nearly always picks a freq. near 200 on autotune. Mind you one time it did go to 90 and I did pick up a 4 oz specie.

Staples

maybe there is a difference between a Monday tector compared to a friday tector when everyone is iching to get on the piss at the local

Everytime I use auto tune it puts me around 200.

Have been leaving the tector in manual and as soon as the country or interference gives me heaps I adjust the tuneing up 20 basis points and it shuts up. Can do this 5-6 times per hour on occasions.

Trains at one side - high tension power lines at the other.

oh ---using a 4500..14" eliptical--something like that--the tags are worn off the plate.

Regards
Oneday69

The only time i tune with the coil vertical is when im working creek walls.

You use your detector with the coil in the horizontal axis, (txing vertically) why would you want to tune it in the vertical axis.??(txing horizontally)
I could never understand this even from the manual.

I guess on some occasions the horizontal axis tuning has merit.
Never dismiss it completely from your arsenal of tips & tricks.
All tips & tricks come in handy on those days when all else fails.

"The only time i tune with the coil vertical is when im working creek walls."

That's a good tip Narrawa.

I used to auto-tune the 4000 by the book but changed to having the coil on the ground with
the 4500 and 5000. I always up the gain to maximum the motion to fast when auto-tuning.

I actually had the lowest reading I've experienced two days ago. 56

Robert

Very interesting.
Always used to lay my old 2100 on the ground with coil vertical while tweaking the screw to tune it. This method proved excellent when using the dust bin mono, the threshold was very stable. So much so several prospectors actually used my 2100 to prove just how stable it was in ground they felt wasn't possible to use a mono?
Now see many are laying the coil "flat" on the ground with the GPX's?
This makes a lot of sense in areas, (which are common) in WA remote areas where EMI is almost no existent when the sky is clear and no thunderstorm activity in a 200km range.
Will certainly keep this handy tip in the memory bank when we get back out there in 2012.
We have found the auto tune almost always settles around 200+ so we almost always use manual tune when using the 11" Commander monos.
Many thanks for all the worthwhile tips.

Peter

SEEMS LIKE WE ARE NEVER TOO OLD TO LEARN NEW TRICKS PETE.
REGARDS
0neday69

Disconnect your detectors coil lead from the control box, turn detector on, up the gain, up the motion, up the audio to boost(GPX models).

Do an auto tune, whats the detector now trying to tune out.??

Does upping some settings work???? or add to the problem??
Test your skill with the manual tune now.

Thanks for that tip on Auto tuning with the coil on the ground....I have never tried it with my 4000. I detect with a pair of mates who use GP`s and have to auto tune(coil raised and pointed in their direction) their Detectors out sometimes if we they get within 30 mtrs or so.