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NF 17x11 running quiet

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Post  goldmuss78 Fri Jan 20, 2012 4:32 am

Hey guys, running a 4500,
Ive had my nf17x11 for a while and havent really found too much with it as i find it hard to take the smaller coils off.

keen to chase some bigger nuggs, so ive been doing a fair bit of practice in the backyard with it Very Happy . It is a bit of a casual observation,
and with only air tests and a few shallow targets, but there doesnt seem to be a lot of difference in the signal response or depth advantage, when running say rx 8 and stab 7, to say rx 12 and stab 7?. with the smaller coils running the rx higher is clearly better for signal response and depth, so i usually put up with a bit of noise when im using them. At this stage i would be keen to hear from people who use 17x11 to see what they recon, id love to run it super quiet with a low rx if im not losing too much depth, it would make life a lot more peaceful Smile

i know my tests seem a bit dodgy, so keen to hear what some folk think,
cheers
GM




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Post  Narrawa Fri Jan 20, 2012 9:19 am

.......i find it hard to take the smaller coils off.

G-day GM, im a regular user of the 17x11, and have been since the first of the white super light models and still use it today on my 4500.
Iv found gold from a poofteenth of a gram to 2oz with this coil from sun bakers to depth.
If coming off smaller coils you will have to re educate yourself to how they respond on targets, by employing a bigger coil you can be assured it has the depth capabilities your looking for.
As for the settings, not much different to setting it up for an 8" or 11", most of the changes are going to come from you in the way that a target pulls you up for investigation.
When you change to a bigger coil you'll find your not hearing targets in the same way you were when using the smaller coils...they tend to loose some oomph, thats normal, yet you'll also find that deeper targets are now audible.
A typical example is the common shotgun pellet, not as loud close to the surface, but now digging them from greater depths once conditioned to the transition from small coil to big.

Small coils tend to run quieter EMI wise, but tend to be more sensitive ground noise wise. The bigger coil looses some of its sensitivity to the smaller targets close to the surface but makes up for it with its depth capabilities.
However, they are bigger and you get a little more EMI to deal with, and this is where you'll find yourself tweaking your stabilizer down to numbers not of the norm. Dont let that worry you because you have now opted to chase bigger deeper targets by upping your coil size, and with that comes some conditioning.
Let the coil do most of the work, even if using FP on the 4500 it will seek out the deeper bits compared to the smaller coils due to the larger design of the coil. By starting out in the FP settings you'll find what your looking for when you ask ........
id love to run it super quiet with a low rx if im not losing too much depth
From here is where you start to tweak your settings to find the happy medium for operations on the day.
The stabilizer works much better at suppressing EMI than it does ground type noises in my opinion, but when its not needed leave it around the norm 6-7-8.
In some cases it will take a smidgen off the response to shallow targets if running it below the norm, if your aware of this you tend to play around more with these kind of signals. However, if your running a big coil your not really looking for small gold, they are the bonus bits, yet can lead you to the deeper bits.
Classic example of this is if your digging lots of small targets/gold and sink a 30" hole right in the guts of the area. Gold or junk, something pulled you up and you were able to adjust your mind set from digging the tiny bits and dig a deep hole.
Many big holes will turn up zero, yet if your digging a few of these you know its only a matter of time, point is your now digging holes you would normally not. They may not all be very deep targets and they may not all be gold, but your doing it all with a bigger coil.
Mind set complete, your now looking for signals shallow and deep that are almost none existent.

There is no magical settings, the magic comes from you.




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Post  goldmuss78 Fri Jan 20, 2012 9:47 am

Mate! thanks so much for taking the time to reply in such an in depth fashion. answered my questions and more.

You pretty much read my mind regarding stabilizer, i have found running it under 7 with the smaller coils decreases sharpness of the small targets it finds, so i was planning on leaving it on 7 forever regardless of coils. Ill have a play with that for sure, as ive been basically trying to reduce emi, and my tactic was to just reduce the gain and trying to manually tune it.

cant wait to get out there a trial it some more! bounce

Cheers!
GM

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Post  deutran Fri Jan 20, 2012 11:13 am

Hi GM
Narrawa pretty much summed it up and is great advice.
Just to add the difference will be seen in the deeper odd targets you will dig.This you will notice straight away.After some experience with this coil you will become accustomed to finding the smaller targets at depth.
The reason we use the larger coil is simple,it gets the larger deep targets and is very capable on small gold thanks to the sensitivety of the newer detectors.In fact larger coils like the 18"round and the big ellipticals can detect small gold when coupled with the newer detectors better than the early detectors with small coils.This can be seen by the amount of small gold being won over well worked areas missed previously by other combinations.
Try running the 8" over a test patch with larger deeper targets and the results are very clear,a bigger coil is required.The 8" is used for specific situations such as high EMI,gullies or rocky areas or chasing very small gold or specimens.
A recent example I had after working gold producing areas with the 8" where there was a few quartz specimens I put the 17" on and dug 5 deep holes.Found 2 very old rusted pocket knives and still digging the other 3 already over 2ft deep.
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Post  mulgadansa Fri Jan 20, 2012 1:29 pm

Gday Guys
Don't know if the East is like here but I've found over the years that the bigger coils get left in the shed towards the onset of summer. When it's cold you can get away with almost anything but as summer approaches the ground here starts getting very narky and I settle for the 14x9 NFA. Can use that unit anywhere. I'd say that you've got about a four month window in the west, June-September, where you can get away with the big coils. Sure they'll work at other times but the extra noise is tiresome and you'll miss stuff.
Downsizing coils in the afternoon in the latter part of the year, seems to cope a bit with the emi issues.
Maybe it's just because there are so many Telstra towers/ minesites etc around here, that generate a lot of interference.
cheers
Brett
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Post  Narrawa Fri Jan 20, 2012 5:36 pm

Brett, your probably right mate, im yet to learn the effects of EMI here in the west and its continuity.
Have not taken the 17x11 off since being here, yet have only worked the one area, and may not have had the pleasure of experiencing the arvo EMI effects, or perhaps its not kicked in yet. ??
Im probably a little erratic when it comes to settings and tolerate more than i should when it comes to EMI....something that im sure will remedy itself soon enough as i get familiar with WA conditions during the hotter times.
Iv already found ground that the 4500 works only while the coil is held above your head. Shocked


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Post  mulgadansa Sat Jan 21, 2012 2:50 am

Gday Narrawa
I'm fairly intolerant of the "noisy coil". A mate of mine swings a 18" Coiltek and a 25" NFA and it's got me beat how he puts up with the crap they both generate all day, yet he is extremely successful with them. As I said I very rarely take the 14x9 nfa off the unit now.
I prospect in the Murchison/ East Murchison in an area from Meekatharra to Leinster I guess. Plenty of good noisy ground there. Some areas are strictly DD country. Are you over here now?
cheers
Brett
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Post  Narrawa Sat Jan 21, 2012 6:54 am

Brett, yes im here in WA now for the long haul, getting a heads up on how it works over here before the winter rush, and when it does i should have a good hiding spot. Laughing Laughing

I'll try to explain why i think some of us tend to run on the high side of comfortable.
Putting up with more noise than one should i guess has its down side, but at the same time its not all reckless thinking for those that can tolerate a little chatter.
At a guess id say many who like to run a little chatter'y, tend to listen mainly for the slight rise when over a target....something thats not present with atmospherics. That slight rise is sometimes not present when running conservative settings either, and is not always present with each pass. Its just enough to make you want to have a play with it....many times leading to nothing. Much the same as when running the detector with a smooth thresh....yet the high side tends to pull in just a little more signal from targets....along with the chatter.
Not something that many are comfortable with, and yes can at times be challenging, but backing off the settings once your accustom to the noise tends to bring with it a sense of loss, and you soon start trying to find a happy medium between yes and no.
Much is ground dependent, if the ground says no you can't then thats the end of the story, your forced to back off till its able to cope.
Swing speed is probably one of the more important properties, have you ever just sat the coil on the ground and had a listen, yet when it moves its a different story.? Thats instant learning right there for those swinging bigger coils yet still looking for small gold.
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Post  mulgadansa Sun Jan 22, 2012 4:23 am

Gday Narrawa
Welcome to WA then Very Happy Yeh from memory I think the machine chatters away to itself quite happily when still. Haven't been out for a few months now, weather and a new grandie tying things up.
Been a fair bit of rain and thunderstorms in the Murch/eastern goldfields lately too.
Don't get me wrong, I run my 4500 a bit on the lean side but my mate goes back to Normal and amps the gain and stab right up and I wouldn't be able to recognise a positive signal amongst the jibber jabber he generates. Happy mediums I reckon and the ground varies a heap to keep you on ya toes.
cheers
Brett
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Post  Narrawa Sun Jan 22, 2012 4:41 am

my mate goes back to Normal and amps the gain and stab right up and I wouldn't be able to recognise a positive signal amongst the jibber jabber he generates.
Yep ok....im outa my realm on this one... affraid ..i can run in Normal/s/exstra....but i go the other way with the gain till it balances.
Cheers for the welcome.
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