SPP HICCUP

[old hand]

Hi I thought starting a new post on this subject . After adding a ten turn vernier yesterday on top of the SPP ground balance it did not cure the hiccup problem but it really improved setting up the ground balance. After speaking to Dean at Gold Search he has mentioned it to Whites but has not had any reply as yet, I emailed Whites today and asked is there is any cure to stop the hiccup and can a 10 turn pot be added to the ground balance we will see what they say regards john

 

[Reg]

It appears the hiccup is dependent upon the ground signal intensity. So, this is difficult to about impossible to duplicate here in the US where the ground isn't nearly as bad. So, my question is, can someone make a you tube video of the hiccup and show when it happens so we can see and hear just what is going on.

If a video is made, please try to show what makes it better or worse. I suspect sweep speed or jerky action clearly makes it worse, but what else seems to have an effect.

Video examples will make it better to analyze.

One forum member indicated that he added the Conductivity switch and this switch causes the hiccup to change to a brief hic or kup depending upon the setting of the switch. The forum member indicated the single tone mode helped considerably in dealing with the problem. It would be nice to see this example also.

So, any and all help any of you can give in displaying the problem will help.

So, in simple terms, I feel you need to help in providing as much information to help in curing the problem.

Reg

 

[Roscoe]

This is what i know about the hic-cup sound.

1- The higher the gain the more pronounced the Hic-cup sound is.
2- The HIC is the sound of the coil coming down onto the ground.
3- The CUP is the sound coming off the ground.
4- The CUP is a stronger signal then the HIC.
5- Conductivity switch set to LOW conductors you only get the CUP.
6- Conductivity switch set to HIGH conductors you only get the HIC.
7- Conductivity switch set to ALL you get HIC-CUP.

The conductivity switch does make a vary noticeable difference to the machine. I only wished the CUP sound was on the HIGH conductive side and not the LOW, as this is the most noticeable sound. If you run the machine in HIGH conductive mode it runs unbelievably quiet because you only hear a small HIC sound.

 

[old hand]

Reg the hiccup is there with a steady sweep speed to find deep targets you have to go low and slow I do not have a video camera some of the other member may have one .Today on one slope it hiccupped a lot on another part of the same area it was as quite as a mouse beautiful smooth threshold hope some does a video regards john

 

[Roscoe]

Reg, Could you please explain more about this Ground Balance internal pot. I have seen this pot inside, its a plastic square pot with an adjustable dial on top. What would be the factory procedure for adjusting this pot and how do the factory know when its correctly set? The only reason i ask this is the hiccup sound as i see it is associated with the ground balance circuit and maybe by extending the GB range it might help in counteracting or reducing the hiccup effect?

There is something else i should add into this hiccup effect and that is the factory ground balance preset mark. I have never encountered any soil yet that this preset mark lines up with at all. The soils i work in are from 7-8 and usually around 7.5.

Would be good to know what other SPP users are finding their GB balance point is on the soils they operate on? This should give us a basic idea of the soil differences from Australia to that in the U.S?

 

[old hand]

Roscoe I think with the ground balance mark there are going to be variables , coils for 1 same make same size they are all different between 7-8 that's where the ground balance is most of the time . .I think its how the detector is reading the ground when it hiccups it seems to be when the ground changes, today I was out on some burnt ground the detector hiccupped on spots where there had been a branch and all that was left was ash. You could see where the branch had been once passing over this the detector hiccupped. I will wait to see what Whites have to say regards john

 

[Reg]

Ok, I will try to explain a couple of things. First, the one internal square pot is part of the GB circuitry and can be used to set the adjustment of the external operator adjusted pot. Just what is used or just how it is set is something I can't answer. However, normally almost all operator ground balance controls gB at the same setting, thus if normal is 7.5, then all detectors should be the same.

Unfortunately, I can't say if all are set the same or what is used to obtain this setting. What one can do is measure the small square pot's resistance from leg to leg. One way, the two legs on the same side should measure the total pot. Measure from the one leg by itself to the other two and write this down. Also, mark the dial with a precise marker. Now you have the original settings, so don't lose this info.

Ok, now, increase the setting by turning ccw or counter clockwise you should be able to increase the range of the GB, providing it isn't already at maximum. My selection of which way to turn it could be wrong if what I am looking at is wrong. Either case, always remember the original resistance and you can go back to factory setting.

The other way to calibrate this internal pot and that is to pick a test bed and see what the setting is now to GB at this location before any adjustments are made. Then adjust the internal pot and see what the new GB setting for ground balance.

One other thing to know is a PI will not detect ashes. It will detect the soil below those ashes that probably has changed to maghemite. It may seem like the PI is detecting burnt wood, but it isn't. IF you don't believe me, take some charcoal and try to detect it. A sensitive VLF will detect the charcoal but a PI won't.

I would think that coils made for ML detectors are touchier to GB than Miner John's or factory mono's. Let me know if you find this to be true.

Now, I have not tried this, but it might work. On some DD coils, they are made such the ground signal is partially neutralized by the positioning of the windings. This is great but can impact signals from very small gold. If you take a real small piece of lead foil tape like that used as a weight on golf clubs, you might be able to position that small foil piece on or near the overlap zone and alter how it detects small gold. This might also adjust the GB setting just a little. It will take practice to see if this is true. Unfortunately, on the SPP and SL, sweep speed is the big factor when it comes to detecting small gold.

On VLF coils, foil might be too much to use so they can or sometimes use small ferrite tape to balance a coil.

Reg

 

[Reg]

The hiccup is complex and not easy to explain. Now, keep in mind the gain of the ground channel op amp used in the GB is a lot greater than the gain on the main or gold channel. If the ground changes and becomes more intense, the gain amplifies this signal thus making it larger. This will cause the signal to take longer to drop back to normal because of the action of the autotune high pass filter. So, in a nutshell, the two signals (the gold channel and the ground channel) take different times to return to normal.

The blanking of the back half of wee/woo or woo/wee is determined by the signal on the time it takes the gold channel signal to be reduced. If one of the two channels still has energy when the other is done, that could cause the hiccup.

To complicate matters, the noise reduction circuitry sort of rectifies the noise and shifts or offsets the signal just a little causing the noise to not be heard. All of this gets complicated and confusing when signals exceed the norm.

Now, one could build a blanking circuit that could be adjustable that blanks all signals for a finite time. This would or could be adjusted to inhibit hearing the hiccup.

Then there is the possibility that changing the present technique on how the signals are blanked and be able to do the same thing.

None of the ideas are that simple or easy to do. However, maybe simply changing some timing features of the present design might work. I just haven't spent any time on this idea up to now.

Reg

 

[Guest]

Reg is it possible to just adjust the delay control a little (12usec) when the ground is causing this hiccup to be a nuisance?
Would this stop the hiccup? If so it would be worth adding a delay control.

 

[Roscoe]

Zuke, I was thinking the same thing today. By raising the pulse delay slightly it could remove some of the ground signal which allows the machine to ground balance easier, but still remain on a high gain. But by doing this does that give any advantage over reducing gain and staying on 10 usec? What have you found with testing on your TDI PRO Gain vs Pulse Delay Zuke. I do some beach detecting and the pulse delay would help in this regard. Tomorrow i will fit pulse delay to SPP and see how it goes.

 

[Guest]

The reason I mentioned it' seams to stop a lot of funny behavior on the TDI pro in bad minerslisation and doesn't seem to loose to much sensitivity on tiny gold over .1 gram
I'd have to say I'm quite impressed with both machines (TDI pro & SPP)

 

[dazza513]

I remember seeing on a YouTube vid with a tdi sl that a slight adjustment of the pulse delay made it a lot more stable whilst useing the conductivity in 'all'

 

[Reg]

Hi Zuke,

You might try unplugging the freq pot connector from the freq pcb connector on the pcb and moving the pot connector to the delay pcb connector and see if the delay works. If it does, then you can see what it does in your ground. My guess is it will help for a couple of reasons.

The nice thing about the test is the two pcb connectors are right next to each other.

As I mentioned in another post, the freq pot is identical to the delay pot so it should work. Also, the best I know, there was no modification of the software, so I am hoping I am correct that it will work. The only reason it wouldn't work is if there were software changes and I am fairly certain that didn't happen.

Next time I have my SPP open I will try this also.

Reg

 

[Reg]

Hi Zuke,

I don't remember if you indicated you had some ML coils but if you do, you might test to see if the ML generate more hiccup signals than those made by Miner John. Hopefully, the Miner John coils will be a little more stable.

Please let me know if this is true or not.

Reg

 

[old hand]

I don't no much about the TDI OZ but if you alter the pulse delay you can loose small gold doing this on the spp means you are leaving gold behind and there is a lot more small gold around than large bits .The hiccup happens with all coils razor back ,nugget finder , minelad you can get it to do it with a DD if you play around with the ground balance. The tests that I did with DD coils the performance was terrible compared to mono s I dont is the coils as it will do it with DDs Its a electronic problem regards john

 

[Guest]

Unfortunately as minelab coils are not real suited to the TDI or SPP iv moved on the lot and purchased all razorback coils instead' my reason is they are an improvement.
I haven't spent a lot of time using the SPP but it did hiccup once or twice but iv put that down to mineralisation, sweep speed and coil height' but I think if it was becoming a major issue lifting the pulse delay would solve it in a bad location and I will try it out when I get a chance but I personally don't have that big of issue with it.
If it is an machine issue you need to compare it to another machine as it sounds like your having a lot more trouble with the hiccup than others.
Update
Just tried plugging the freq pot into the Delay and it doesn't the detector became unstable and I swapped it back'
It could work out of town but I'm only hopeful.

 

[Roscoe]

I plugged the frequency pot. into the pulse delay this morning. I don't think the pulse delay works, i tested on the bench with a .4 gram nugget and wound pulse delay up and down and the signal on the small nugget remained the same. I adjusted it with GB on and off. Just to make sure i took SPP down the back and it made no difference to ground balance and Hiccup sound.

I don't believe whites will do any thing about the hiccup sound, as it only happens at higher gain levels. They will say the soil in your area is highly mineralised and to reduce gain to stabilize machine.

The conductivity switch made the most difference to the stability of the machine and the effects of the Hiccup sound in my testing. I found this Conductivity switch feature also removes a lot of bad ground noises by removing the bad ground signal altogether or making the signal choppy.

 

[Roscoe]

I tested commander, nugget finder and whites coils it makes no difference in regards to hiccup sound and ground balancing in general on the SPP.

I tried a commander 11" dd coil as well, the coil ground balanced but the coil would not work at all on the SPP. It wouldn't pick up a 1 gram nugget 2" below coil and the coil continued to false on every thing, it ran weird.

One last observation and that is, I believe the hiccup sound is always there but only starts to surface as the gain rises. I have started out at low gain and slowly raised the gain and you can hear it slowly creeping in until its noticeable at gain 4 and above.

 

[old hand]

I was out today running the standard coil with the gain at max on the burnt ground it was ok tested it on a piece gold of and ended changing the coil as the response was terrible .With the 12x6 nf it had a much sweeter response, back to the gain once I turned it back past the mark there was no response at all on the gold. At the mark it hiccups regards john

 

[Roscoe]

Oldhand, I couldn't understand the NF coil part mate it got a bit confusing. Could you explain that a bit again thanks.