Slight problem with TGSL EDU

[Turjake]

Hello!

I have been making field tests with my tgsl for a while now and I found that iron keeps breaking trough. Even small iron object give a short, broken beeps or beep only once. Problem seems worse in clay ground and is really a nightmare in trashy places. Otherwise detector works really OK and I have already found many coins and my first gold and silver! Here goes some troubleshooting info:

Coil inductances within specs, tested with two coils, problem persists.
TX Frequency 14,25kHz
Depth OK, fat juicy beep for 1 euro coin at 32cm
Foil gets discriminated correctly
Ground balance adjustments don't help

I'm thinking of faulty component somewhere but what could be the most possible culprit?
Can I play with RX and TX phase shift without making a new coil?

Thanks for your replies!

[Jerry]

It looks like like you have it working pretty well. Are these random beeps like when the sensitivity is set to high or is it actually sounding off on small iron objects?

Also there is a relationship with chatter and ground balance and also sensitivity. I find it hard to get a good ground balance when Sens is set too high on the TGSL EDU unit however, on the original Ivconic board, I am using a 10 turn pot for ground balance which seems to be able to get the GEB dead on.

One further thought. Where are you running the Discrimination at? You said that you have already found gold with it which implies that you could be running fairly open to accept down into the foil range. If this is the case I can not comment much because I run mine to just accept nickels or maybe high depending on how much I feel like digging. So have not experienced how it behaves with a foil like Disc setting.

From what you have said so far, it does not sound like you have anything wrong with your detector, it may be a matter of playing with the settings a bit.

Anyways, congratulations on building a working detector. This sort of tweaking problems are the good ones to have.

Jerry

[Jerry]

Can I play with RX and TX phase shift without making a new coil?

Thanks for your replies!

Just reread your post and see that I missed commenting on one point. Yes you can still tweak the RX TX phase relationship by playing with the value of C6 for adjusting RX or C1,C2 for the TX.

I also have played around a bit with adding a 20 Pf paralleled on R17. I did this because I was not able to disc out zinc pennies and the added capacitance took care of that. Actually I started out with 65pf which enabled the unit to disc out quarters, so 20 is a good compromise. That was on the Ivconic board. For some reason, the EDU board disc's out zinc pennies just fine. Component tolerances I suspect because I am using the same coil.

Jerry

Here is a post I made on the subject a while ago. #1059 : http://www.geotech1.com/forums/showt...823#post149823

[Turjake]

Ok. Thanks for you tips. Maybe my improper ground balance setting is the issue here. A multiturn balancing pot is a good idea, I will switch to that. Can you also tell me about your ground balancing method? I've only used the wave lump of ferrite in air method. I'd like to hear a "really detailed ground balancing guide for dummies" version if that is possible.

[Jerry]

Ok. Thanks for you tips. Maybe my improper ground balance setting is the issue here. A multiturn balancing pot is a good idea, I will switch to that. Can you also tell me about your ground balancing method? I've only used the wave lump of ferrite in air method. I'd like to hear a "really detailed ground balancing guide for dummies" version if that is possible.

I have really been around that block on that very issued once I started using the TGSL on a daily basis for hunting. What I found it that you can get very close to proper GEB by throwing a piece of ferrite on the ground and tuning the GEB to just silence that. Since the ground is included in that process, you are reasonably close. Close enough so that you can hunt that way.

However it is best to be able to get the detector to ignore the ground completely and you can accomplish that by pumping the coil up and down (about 8 or 10 inches). When the ground balance is not correct, you will get a beep at the top or bottom of you pumping action depending which side your are on.

Pumping the coil slowly and tuning the GEB at the same time to find that point where the ground is simply ignored is the point that you are looking for. I find that even with a ten turn pot, the setting is fairly critical. I suspect that I will be using 10 turn GEB controls of future projects. Right now I have one of each and the 10 turn is far better.

This is an important but interesting subject and I hope that some of the old masters will jump in her and add their nuggets of wisdom. I think a Dummies or How To manual would be of help to lots of people. After all building the TGSL is only are part of the fun. Actually using it to find things is another.

Jerry

[satdaveuk]

I have really been around that block on that very issued once I started using the TGSL on a daily basis for hunting. What I found it that you can get very close to proper GEB by throwing a piece of ferrite on the ground and tuning the GEB to just silence that. Since the ground is included in that process, you are reasonably close. Close enough so that you can hunt that way.

However it is best to be able to get the detector to ignore the ground completely and you can accomplish that by pumping the coil up and down (about 8 or 10 inches). When the ground balance is not correct, you will get a beep at the top or bottom of you pumping action depending which side your are on.

Pumping the coil slowly and tuning the GEB at the same time to find that point where the ground is simply ignored is the point that you are looking for. I find that even with a ten turn pot, the setting is fairly critical. I suspect that I will be using 10 turn GEB controls of future projects. Right now I have one of each and the 10 turn is far better.

This is an important but interesting subject and I hope that some of the old masters will jump in her and add their nuggets of wisdom. I think a Dummies or How To manual would be of help to lots of people. After all building the TGSL is only are part of the fun. Actually using it to find things is another.

Jerry

Hi Jerry
Id say you have more or less wrapped that one up for setting the TGSL up.
However its very important to have a few coloured metals with you until you know the machine as its easy to not see the ground but also not see certain coloured metals as the TGSL disc and ground balance do react with each other quite alot and its crytical for maxium depth detection.
Its ok to have a oneway hit with iron in disc mode with the TGSL aways look for the two way hit, to me a oneway hit on iron is telling me that im on border line which means you will get two way with coloured
Also as important its a must you run between all metal mode and disc whilst searching like the Fisher 12x range otherwise you will certainly miss things.
Lot depends on what your looking for and where your looking, far as typical pasture land in England looking for relic, go all metal then when you get a hit go for the double hit, then disc with control at bare minium, toggle between the two, do the normal sweeping over the hit if you get one or more two way hits in that mode then dig.
Keep in mind though even if you get a one way hit doesnt mean its junk, it could be deep heavy corrosion mixed with iron particals, its cases like this is where discrimination goes stright out the window with any metal detector no matter how much you pay for it.
Thats when you need to deside do you dig or not, I personally dig for almost anything within the first 4 hrs detecting and that normally my best finds proberly because im digging where the last detectorist didnt.
It goes to show actually that people have gone out and payed megga money for deep seekings machines with all bells and whistles and not making the finds they could do because they will only dig what there machine tells them instead of lisening to the raw data and desideing for themselfs like your well wethered detectorist.

Regards

Dave

[satdaveuk]

Hello!

I have been making field tests with my tgsl for a while now and I found that iron keeps breaking trough. Even small iron object give a short, broken beeps or beep only once. Problem seems worse in clay ground and is really a nightmare in trashy places. Otherwise detector works really OK and I have already found many coins and my first gold and silver! Here goes some troubleshooting info:

Coil inductances within specs, tested with two coils, problem persists.
TX Frequency 14,25kHz
Depth OK, fat juicy beep for 1 euro coin at 32cm
Foil gets discriminated correctly
Ground balance adjustments don't help

I'm thinking of faulty component somewhere but what could be the most possible culprit?
Can I play with RX and TX phase shift without making a new coil?

Thanks for your replies!

The short broken beep or the one beep is telling you that its working correctly, you will find when you get the two beep ie sweep and return sweep, which is double hit, then dig it.
If you get a single hit dont just walk away,you need to turn 45 degrees then swing again and so forth, if at anypoint you get a good solid two way hit then dig it, although I dig on faint two way hits for the deeper stuff.
The way you and Jerry is doing it you will only get shallow coins/ objects thats got pure soil/sand around it, you certainly will be missing most of the good finds thats either deep or mixed with crap.
If you want advance ways of using the TGSL to full advantage follow Fisher 1265x techniques, I own one of these together with many more models/makes although different design detector there quirks are similar, and theres a abundance of tips for real use on the net.
You can tell alot not just by wether you get a detection but how it slopes off during the sweep, for instantance ... foil will give more of a crackle on a sweep rather than a nice beep, but so quite often will small silver, so do you disc that out?? gold can come in anywhere depending on its proof and what ground/items lay around it, remember its a alloy, so what do we do disc that out.
Really disc is only good for certain coins and even then you will miss things, and thats why you need to try and get into habit of toggling between all metal and disc working them together.
If you want your TGSL/ any detector to be silent on the ground apart from coloured metals then you must be prepared to loose out on many finds.
Hope this helps a little

Dave

[Turjake]

Damn. Guess those manuals are worth a read sometimes. Fisher 1266x manual explained pretty much everything. I'm glad to know that the machine is working ok. Now I've only got lots of happy learning to do in the field. Thanks Dave.

[satdaveuk]

Damn. Guess those manuals are worth a read sometimes. Fisher 1266x manual explained pretty much everything. I'm glad to know that the machine is working ok. Now I've only got lots of happy learning to do in the field. Thanks Dave.

If you do a search on the net for the 1265x, theres a forum, buggered if i can remember the name, but its stacked with very good advise from some boneafied detectorists.
Alot on here and elsewhere have done mods to quiten this particular model down, but these boys wont have any of it because they use the chips and chirps to identfi the find themselfs listening to the raw data.
As i said previously theres nothing wrong with the discrimination of TGSL if kept to minium but actual searching better with all iron , once you got a hit then by all means switch to disc and adjusting as you feel fit, of course depends how much junk your prepared to dig, theres no free meal tickets when it comes to metal detecting no matter what machine you have.
If you go to metaldetecting uk you will find a very helpfull tuturial I posted 2-3 years ago on this very subject .
Regards
Dave