SD2200d Ch1 vs Ch2

Hi guys (& girls).
Even though I was extremely confident with my SD2200d both in depth and sensitivity, I was having a little problem with waving/oscilating pulses, so I sent it back to Minelab for "service/tune up". They updated and changed some resistors and capacitors and internal loopcoils. I took it out detecting and was far less than happy with the result. It still had the oscillating pulses, but that wasn't my main concern - because now it was that the detector almost felt like a different machine. It did not have anywhere near the depth capabilities as before and sensitivity had gone far down. It now could not pick up a 6 gram nugget at 9" when before it's operation at Minelab, it had NO trouble finding it - in fact it screamed over the target.
After doing some air tests with a solid 1cm lead ball, I found that on Ch2 it could pick it up to about 9" above, but flicking it to Ch1, I lost it after 2". I know Ch1 is meant for large deep targets, but only 2" on an about 10gm ball suprised me, especially since Ch2 went to about 9". A 0.5 gm nugget that this detector found at 2" depth before, couldn't make the 11"DD Minelab coil even make a beep. In fact I had to rub the nugget pretty hard onto the coil to even get any sort of sound.
I never did these tests before I sent my detector in to Minelab, I never needed to because it was damn GREAT (I would go as far as to say it was one of the best in the world), but since it's come back, it seems to be only about 30% as good as the machine it used to be, both in sensitivity and depth. After sending it back to Minelab for a retest, I've been told that it is working within their specs and there is nothing wrong with the detector or with Ch1. I am so disappointed, as I know it is far worse than before and I wish I'd never sent it to Minelab in the first place and just put up with the occasional pulsing/oscillating, but I did and now I'm not sure what to do.
I still need to get it back and retest it myself to be sure, maybe they've moved something and it somehow now works again.
Has anyone done the Ch1 vs Ch2 test with an SD2200d that can post their results here? Maybe Minelab is right and that's all the depth Ch1 has, but I just don't think so...

Hey CostaDee

Sounds like somethings definitely up on the machine, Ill test my 22 channels next time I go out, but I reckon your right about channel 1...

You know how you just get a feel for what the machine tells you, like how deep or small a target is, and then you change settings, coil etc and it just doesn't have the same feel.....

I'm used to what my 22 tells me, like the "could be gold but more likely lead" sound!!!

Do you ever use the different channels independently when it was feeling right? The instruction manual says that you rarely use independent channels, and that ch 1 is for very noisy ground and you will lose sensitivity, no mention of what ch 2 does, just recommended not to use it by itself...just like the discrimination should have been advised not to use

Hope this helps
Cheers,
GT

Hi CD,

My wife uses a 22, so I cannot give you any info apart from that I will test it next time we go out? I also offer mine as a 1 to 1 test as I see you are in Melb. I'm located in the outer NE subs of Melb, so if you wanted to take a drive out here we can go out about 10 min from here where there is no EMI and test them. ( just an offer )

Regards

Mariner3800
Peter

"I've been told that it is working within their specs"

What specs.... oh yes, the specs that they are not game to publish.... for any model.
$6700 for the latest model and still no specs, keep your fingers crossed that you get a stud and not a dud.

I had a similar problem with my explorer , i sent it back for a new touch screen and when i used i again it was like a different machine and seemed to have lost depth so much so that i bought a new wot only to make no difference . now 6 months latter its hitting coins at 18" plus ( oh my arms ache ) on the beach again so it is like it was . maybe mixing new with old parts ( tecter being 4 years old at time of repairs ) creates differing resistances untill new parts age with the existing . i must mention the screen had not been screwed back correctly on return from minelab ( i still would not own any other machine ) Theory/rant over

Mariner3800, thanks for the offer and I think that's a great idea. I just spoke to Minelab again and they swear that when I get it back this time, I'll be very happy with it. Was a great chap I spoke to who knew his stuff and ran through the different tests with me. Maybe some cable got squashed with the reclosing last time and it's fixed now, whoi knows. Nevertheless, I'll wait to get it back and hopefully I'll end up with a smile on my face this time.....HOPEFULLY.
Will keep you informed after I get it back and test it.

PS charcoal_chaser maybe you're right, but I'd hate to have to walk around the bush for 6 months without getting a signal until it comes good....but still food for thought.

Cheers

Any Time CD,

That's what this forum is all about, if I help others the "Gold Gods" might shine on me?? ( One Day )

Mariner3800

Hi
The truth is that a sd2200 run channel 2 and deep is a great setup.I have personally seen this machine out preform Gp and Gpx Machines in the highly mineralised and variable soil of the Golden Triangle.Running medium to large monos the gpx machine is frought with one problem to get them to operate properly you must use non full timings .Ie sens smooth enhance and fine.So here the rub a 18dd will find a 30 oz nugget at 36 inches.Here an 18 mono on these timings will miss it and on full timings will give false signals to every bit of ground noise and moisture not to mention EMI.So in fact the sd2200 with an18dd has almost an inbuilt discriminator that enables the operator to have a better chance on deeper inground responses.To be brief if you feel your sd2200 has lost its character by repair you will never be happy with it (sell it).these machines are still the back up choice of many of the old time pros and I can see why.Gpx and gp machines rule the top half but the sd2200 has the score on the board for the deep stuff.This only applies in Victoria because of the variable mineralised soil.
Cheers Dig

Thanks Dig24crt for your reply, and I do agree with you about the GPXs with monos in Vic. I have a friend who always used his GPX4500 in enhanced mode with his 18"mono but then after a simple buried target test at 15" showed him that he could not hear that target, but by switching to Normal, he once again could but had alot of ground noise. He had to "dumb down" the 4500 in normal mode to quieten the ground noise but still pick up the target. My SD with its 18"DD would have picked it up (I'm 100% sure) prior to its repair but alas couldn't find it either. I'm sure though that it will work 100% again & I'll be 100% confident in it again, when I get it back this time....at least that's what I really hope! (I don't want to sell it )

Goodluck CD

Maybe Minelab thought your sd2200d was TOO GOOD so they had to rectify the problem, sorry upgrade the programming , so GPX owners didnt catch on .

Dig24crt wrote:Hi
The truth is that a sd2200 run channel 2 and deep is a great setup.I have personally seen this machine out preform Gp and Gpx Machines in the highly mineralised and variable soil of the Golden Triangle.Running medium to large monos the gpx machine is frought with one problem to get them to operate properly you must use non full timings .Ie sens smooth enhance and fine.So here the rub a 18dd will find a 30 oz nugget at 36 inches.Here an 18 mono on these timings will miss it and on full timings will give false signals to every bit of ground noise and moisture not to mention EMI.So in fact the sd2200 with an18dd has almost an inbuilt discriminator that enables the operator to have a better chance on deeper inground responses.To be brief if you feel your sd2200 has lost its character by repair you will never be happy with it (sell it).these machines are still the back up choice of many of the old time pros and I can see why.Gpx and gp machines rule the top half but the sd2200 has the score on the board for the deep stuff.This only applies in Victoria because of the variable mineralised soil.
Cheers Dig

G'day Dig

Just thinking out loud here, I am wondering if a GPX4500 or 5000 with that same 18"DD coil run in normal timings and with the added benifit of gain and stabalizer control would get the same result as the sd2200 on the 30 oz nugget at 36 inches.

cheers dave

Davsgold....I've wondered the same thing, but I don't have one to play with... One day maybe

Hi Dig24crt

Interesting setup with channel two on deep, will have to give it a go...is this setup only for DD?

So frustrating with the deeeeep holes I sometimes have to dig with the 22...one whole was as long as my arm for a piece of iron bar

GT

CostasDee wrote:.... I have a friend who always used his GPX4500 in enhanced mode with his 18"mono but then after a simple buried target test at 15" showed him that he could not hear that target, but by switching to Normal, he once again could but had alot of ground noise. He had to "dumb down" the 4500 in normal mode to quieten the ground noise but still pick up the target.

And some of us still use this method with good results because its thought that 8 on the gain is close to that of the GP series, and it may very well be....but a simple test of winding down the gain till it handles the ground the same as a 3500, will show you its a much lower gain figure, and quite useable over variable ground that any GP series is used on with either coil types. Ya gotta remember, most users of the smooth class of timings are in a rut, and once in it, its very hard to escape back to the old school. Its called being spoiled. I love reading about it because its one of the reasons there is so much gold being found in so called flogged ground that does not warrant the smooth class of timings.
The savvy operator is bias to neither set of timings, because he knows how stupid it would be to pick up gold using only the smooth class of timings and not go for gold using the other.

I dont know of any so called " pro" operators who call upon their back up SD's or GP's while they are using a perfectly functioning GPX.

I have a 2100 as a back up, and only use it when my 4500 is being hired out....its a bordem thing.

Late edit..
The pick is 36" long, and is at ground level, coil 16" mono and i was using sens/extra with a gain of 4. Highly mineralized ground with an ironstone layer at the 15" mark.. Hill End NSW.
No its not a 30oz nugget...its much smaller.

Dave
Will get close but GP and GPX Machines are far more sensitive than Sd 's.Its that very sensitivity that attracts more false responses.
Narra
On a test i did with sd gp and gpx machines(turning back the gain eliminated the target and false responses)Big gold is no longer being found at depth in the triangle.This started at the time of the gp3500 and the reign of the mono.Perhaps its time that Minelab thought about a new deep timing
GT Yeah for a medium to large DD run it with an enhancer and a paper thin threshold.
Cheers Dig

Got my detector back from Minelab yesterday. The note says they didn't need to do anything as it was tested and worked fine. I did some preliminary tests, but let me stress that these were done in the garage with metal objects around and severe EMI. My tests showed that even though Minelab state that nothing was done, the detector seemed to perform far better this time than it did after it's last return from Minelab (maybe by reopening, something was moved or unjammed - who knows). It certainly made a sound when the 0.5gmer was waived infront of the coil and didn't need to be hard rubbed into the coil, like it did before. I can't tell if it's as good (deep and sensitive) as it was before until I test it in the field. Ch1 still performs crap, with hardly a response from 5.5gms of gold waived infront of the coil but Ch2 seemed to certainly scream out to let me know. I wish I had done the Ch1 vs Ch2 test before the first time of sending to Minelab, but I didn't unfortunately. If anyone with an SD2200d, can do a test over the weekend with about 5 to 10 gms of gold (or lead for the sake of this test), by air testing their detector over the target and recording the distance between Ch1, Ch2 and both, that would be great.
Mariner3800, love to take you up on your offer now to compare your SD to mine, when you've got time and it suits...let me know.
Cheers guys(& girls)..

Hi CD,

What coil are you testing with, just want to get it as close to your set up as possible.

Also home all day today and will be about next weekend

Peter

Got a choice of Coiltek 24" 18" 17x12" 14"Elite or 11" and Minelab 11", all in DDs. Today's a little hard and next weekend I've got my kid's b'day party. Any time during the week?

HI CD

JUST TESTED IN MY GARAGE ( NOT THE BEST SPOT ) AS YOU SAY, BUT AS A START IT WAS OK.

WHAT I FOUND IS THAT CH2 IS GOOD FOR ABOUT 10-11 INCHS WITH 8G NUGGET, CH1 WAS GOOD FOR ABOUT 2 INCH, BUT VERY DISAPPOINTING, BOTH WAS GOOD EQUAL TO ABOUT CH2??

THIS WAS TESTED WITH 11" DD

PM ME AND I WILL SEND YOU MY ADDRESS AND PHONE NUMBER, I'M OK FOR ANY NIGHT NEXT WEEK APART FROM FRIDAY.

TALK SOON

PETER

Has anyboby tested Ch1 vs Ch2 in the field yet? Posting your results here would be just great...

Ok guys, update time. Took the 2200 out to the field to "find some gold" after it had come back from Minelab. Now let me say that although they said that nothing was wrong and it tested ok (indicating that nothing had been done to it this time), this machine worked FANTASTIC this time. I didn't find any gold (my usual story) unlike TGC who is gifted with always finding something, but the detector certainly worked a treat. It was finding tiny pinhead rusty targets with the Coiltek 14" DD, like it used to before it's first trip in, but couldn't find after it's first trip and before it's second trip in (hope that makes sense). So I don't believe what they told me at Minelab that the machine was fine and nothing needed to be done, I know they did something that has once again made this detector a "ripper". Thanks Minelab!

Back to the initial question of Ch1 vs Ch2 again. Has anyone tested the difference in target finding between the 2 channels? I'm finding Ch1 to be pretty well useless at any depth compared to Ch2 that far out performs it on any target, but I haven't tested it on say a 30oz gold slug buried at say 30" (cause I haven't got one!). I was told by Minelab that Ch1 is used for BIG gold targets at depth, but I find that hard to believe when Ch2 has out performed it in every test I've done. Almost makes me think that maybe I should consider changing Ch1 frequency (cause it appears to be useless as is), to something a little higher (higher than Ch2) to add sensitivity for the smaller targets. Any ideas/opinions?

Cheers all......

CostasDee wrote: Back to the initial question of Ch1 vs Ch2 again. Has anyone tested the difference in target finding between the 2 channels? I'm finding Ch1 to be pretty well useless at any depth compared to Ch2 that far out performs it on any target, but I haven't tested it on say a 30oz gold slug buried at say 30" (cause I haven't got one!). I was told by Minelab that Ch1 is used for BIG gold targets at depth, but I find that hard to believe when Ch2 has out performed it in every test I've done. Almost makes me think that maybe I should consider changing Ch1 frequency (cause it appears to be useless as is), to something a little higher (higher than Ch2) to add sensitivity for the smaller targets. Any ideas/opinions?

Cheers all......

G'day CostasDee

It's good to hear your got your machine back and its ok again.

Why don't you get a big bit of lead say about as big as a flattend gold ball or tennis ball, which would substitute for a 30oz gold nugget, and try Ch1 compared to Ch2.

If your energetic dig a big deep hole and bury it, which is not as good as an undug target I know, or if not too energetic just air test it. Checking the target in both Ch1 & Ch2. Make sure the machine is ground balanced. Swing the coil over the target with the target just on top of the ground, raising the coil until you just get a target signal. Then make sure the machine is ground balanced and lay the coil flat on the ground and swing the target over the top of the coil until you just get a target signal and see if there is any difference in detection depth.

Then repeat the exercise. with a small target.

cheers dave

find an earthen mound and hand drill a hole from the side ,downwards and insert a plastic tube ,then have a piece of lead or gold on a string and let it down the tube .Now coz you havent opened the ground above the target you will get a very close approximation of a target at different levels

All good ideas guys and I will test them next time I've got time to go out...many thanks. My initial test was using a 10mm lead ball and placing it on the surface and air testing at what height I lost the signal. Ch1 lost it at 2" and Ch2 lost it at 9". I do know that air tests are highly inaccurate but I was trying to compare channel performances under the same conditions. After describing my results to a Minelab person I was told that Ch1 is used to find LARGE DEEP gold nuggets and is not sensitive to other metals (even lead). I find this so very hard to swallow as all my tests show Ch1 to be pretty useless and really lead and gold are fairly even sounding (to me anyway), so why cant I pick up a big piece of lead at a bigger distance than Ch2? Mariner's results should his detector to be similar to mine, so that why I'd love to hear from someone like Ismael or another who is an expert with the workings of these older machines.

That's why I was thinking to look into whether I should oust the Ch1 crystal (if the 2200d has crystals that is) and replace it with something that actually does work.

CostasDee , Don't bother digging more test holes take a trip to the Laanacoorie test site, near Tarnagulla. If you don't know
where it is ask Jim at the Laanacooriecaravan park, he made it.

There are several including 2' and 3' test holes already in place at this site,
take a lump of lead as Davsgold suggested and try the 3' foot hole with a 18"DD but don't be too unhappy If you can't hear a signal.

I for one, would be surprised if you did.

You should maybe get a signal at the 2.5' depth, depending on the size and shape
of the lead target.

I have alway liked theSD2200D and they still work well but for my money for any targets, shallow or deep, I would still prefer most any
of the GP's and the GPX 4500/5000 are better still.

Sorry but that is how I see it.

Hi CD,

Having never used a 2200, I can't be too sure, but on the 2000 and 2100 ch1 is for bigger deeper targets. Small targets will not be detected very well in this channel. Also ground noise will hardly be a problem in this channel either.

As far as changing the frequency of this channel goes, it can't be done, well not that easy anyway. The 2200 is not controlled by a crystal oscillator it has a discrete oscillator setup, which is not the easiest thing to tamper with. Even if you were to speed up the oscillator, then ch2 would pick up more ground noise in hot ground. To change the operation of ch1 you would have to reprogram the eeprom, to do that you would have to remove it first. Then forget about ML repairing your detector in the future if anything goes wrong.

Cheers Mick

Thanks for your input guys. Ok I didn't realise it wasn't a crystral controlled frequency like the 2000 and 2100 and I'm not interested in taking the eeprom out (I'm presuming it's soldered in and not just plugged in). I did have some experience with reprogramming eeproms many years ago, but I don't think I've got any of the hardware or software around still. My main point was that if Ch1 didn't do anything useful & was basically a waste of space, I'd replacing it with something that actually did something useful, but I'll do the deep tests with the big targets before I even consider it.
Thanks guys...