LOOKING FOR DD ADVICE

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LOOKING FOR DD ADVICE Empty LOOKING FOR DD ADVICE

Post  goldendream on Fri Jul 26, 2019 4:27 am

Gday gents (and ladies if any), I have ordered myself an 8" Detecch DD coil and looking forward to getting my hands on it and using it on my 5000.
The problem is I'm starting from a low experience base on the DD use.
I'm going to hit an area in the triangle with high FE trash and near a buried electric(or may be telecom ) line,(from 20 feet and up to 5 feet away).
I'm doing some pre-trip research and I'm wondering if there are any lads\ladies out there with advice in 3 areas re the use of DD in this scenario.
They are ;
1. Using in the 5000 Cancel Mode ......am I still able to discriminate fe targets? Does it cut out completely or reduce EMI? . How are timings affected in this mode? Generally, the best settings in this mode.
In particular, what should I be doing to maximise the effectiveness of the DD in this mode?

2. Using DD in Mono mode. ......I believe this can be done but what advantages or disadvantages in doing this.i assume though, one would not be using it in this mode too close to an EMI source.
3.using the DD in DD Mode .......in the above-mentioned scenario.

I'd greatly appreciate any feedback, comments, tips or hacks.......Cheers,Trev.

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Post  Old Hand on Fri Jul 26, 2019 8:38 am

should have ordered A I COIL
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Post  deutran on Fri Jul 26, 2019 9:31 pm

Hi Goldendream
I actually encountered this senario a few years back and did some experimenting.I was using a 11"DD so the result should be similar.
Firstly your 8"DD in mono will work just like a sadie with good EMI resistance.We used to use the GP series with DD coils in mono with excellent results.
As for 8"DD in DD mode.I can't help on this.
Now the 8"DD in cancel.This will entirely eliminated EMI but at a considerable depth cost.I found using an 8"mono with low Rx gave better depth than a 11"DD in cancel with a small amount of EMI that I could live with.However the 11"DD in cancel still found gold OK as it ran super quiet.
At the time of testing I had power lines on one side and telephone cables on the other.
In DD or cancel mode on DD coils you would use Normal setting.
In mono mode on DD and mono coils you would use Timings.
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Post  goldendream on Sat Jul 27, 2019 5:05 pm

Thanks for that great response mate.That is really interesting and good starting advice.I will play around with those combos and hopefully, i will post some feedback in a couple of weeks after i get out.Should be a very interesting trip and a real steep learning curve. Smile .

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Post  Old Hand on Sat Jul 27, 2019 7:32 pm

8 inch dd near power and Telstra put into cancel run it in normal not special or enhanced bring up the gain and stab use deep on the front inverted response and try boost with the audio , if it gets noisy just back the rx and stab off a bit ,with the discriminator around 4to6 I found a 90 gram near power lines but I was using a 16 inch coil Very Happy
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Post  goldendream on Sat Jul 27, 2019 10:36 pm

Thanks Old Hand ,I will be studying your points printing them out and Deutrans advise, and taking it all with me. Its a lot to take in but all great stuff.
What's your advise on Special,Motion and Tracking timings?. And also Signal and Target V settings?.
Cheers.

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Post  Old Hand on Sat Jul 27, 2019 11:41 pm

Target you can run higher than you normally would being in cancel , i always use fixed ,tracking med,motion slow, signal 19 Very Happy
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Post  Old Hand on Sun Jul 28, 2019 9:03 am

you can bring the volume limit up to 19
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Post  goldendream on Sun Jul 28, 2019 2:37 pm

ok mate thanks for that . Will try it out, see how I go.

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Post  hugh62 on Mon Jul 29, 2019 10:23 pm

goldendream wrote:Gday gents (and ladies if any), I have ordered myself an 8" Detecch DD coil and looking forward to getting my hands on it and using it on my 5000.
The problem is I'm starting from a low experience base on the DD use.
I'm going to hit an area in the triangle with high FE trash and near a buried electric(or may be telecom ) line,(from 20 feet and up to 5 feet away).
I'm doing some pre-trip research and I'm wondering if there are any lads\ladies out there with advice in 3 areas re the use of DD in this scenario.
They are ;  
               1.  Using in the 5000 Cancel Mode ......am I still able to discriminate fe targets?  Does it cut out completely or reduce  EMI? . How are timings affected in this mode? Generally, the best settings in this mode.
In particular, what should I be doing to maximise the effectiveness of the DD in this mode?

               2. Using DD in Mono mode. ......I believe this can be done but what advantages or disadvantages in doing this.i assume though, one would not be using it in this mode too close to an EMI source.
               3.using the DD in DD Mode .......in the above-mentioned scenario.

I'd greatly appreciate any feedback, comments, tips or hacks.......Cheers,Trev.
 

                  Well as much as I might love big DD coils ,but only in certain ground types and using SHARP , the bulk of my detecting in chasing '' DEPTH ''is by using MONOS .Besides I reckon that using DD's to there full potential is bit of a '' ARTFORM IN IT'S SELF '' !! '' PERSONALLY'' if it where me going to the GT i'd be taking as many mono's as I have with my 5k ,based on the fact that the area is world wide known reputation for the amount of Gold extracted out of there ,and the fact also that its been flogged with every known detector repeatedly .
                 1. cancel mode ; those buried cables should only produce a broad ground noise .EMI i'd be surprised this time of year ,there'd be any EMI Question I do presume your not refering to noisy ground as EMI .
                  2. DD in MONO mode ,will make it more sensitive ,mostly with shallow targets .
                 3.DD in DD mode ,yes there's times I've been guilty of using it ,but only in the worst case scenarious ,and in order to keep the remaining sanity I have left in place .But in a place like the GT and its history ,i'd personally be sucking it up ,the junk that is .  
                   I personally love the 5k ,with its 8 timings and multitude of audio filter options ,complex at first yes ,but by chasing your intended target size and matching a coil to suit and the audio options to suit it ,it still surprises me to this day what you can screw out of them .
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