D2 coil question ???

[Sonny1965]

My second time out with the V3i today and at the end of a swing or bumping into stubble in the field the detector would false. I do not have my coil cable wrapped too tight.I adjusted my gain down and it didnt not help in any preset. Is it just a bad coil ?

 

[Rob (IL)]

DD coils a subject to make the noise when bumped. If you lift on the end of your swing that will cause the problem.
I'm not saying there isn't a problem.
Will it do RX15 in the air without overloading? Go into zoom on the sensitivity window, if it under 20% send it to me.

 

[Ytcoinshooter]

DD coils a subject to make the noise when bumped. If you lift on the end of your swing that will cause the problem.
I'm not saying there isn't a problem.
Will it do RX15 in the air without overloading? Go into zoom on the sensitivity window, if it under 20% send it to me.

Rob, maybe you could expand a little on checking out the DD10". I thought if signal loss exceeded 20% there might be a reason to send the coil in. Checking for stability in the air at a gain of 15 is clear. However re: air stability @gain=15: wouldn't filter selection affect stability based on surrounding conditions? I think I'm missing something here.
Thank you.

 

[Rob (IL)]

Rob, maybe you could expand a little on checking out the DD10". I thought if signal loss exceeded 20% there might be a reason to send the coil in. Checking for stability in the air at a gain of 15 is clear. However re: air stability @gain=15: wouldn't filter selection affect stability based on surrounding conditions? I think I'm missing something here.
Thank you.

No Signal% exceeding 20% would not indicate a bad coil. You are checking the null of the coil. If it will not overload at RX15 Whites considers it a good coil. His bumping noise could be a loose shield wire, if it is Whites would replace it.

In the Sensitivity Zoom window, you see the signal strength at a percentage of when the detector overloads. The goal is to keep the ground signal about 20% so that you still get depth and can still see shallow targets without overload.

The Noise% measures the External Interference. A low number indicates very little external noise and low ground interference, thus allowing for using a higher preamp RX Gain. A high % reading of Noise of 50% or more would require you to try; 1) Freq Offset, 2) Decrease RXG, 3) Salt Mode, 4) 22.5Khz Single frequency, 5) Filter change, 6) Smaller coil.

If your noise is Ground noise you can try; 1) Filter change, 2) Decrease RXG, 3) Salt Soil 4) Salt Mode, 5) Increase BCR, 6) Smaller coil.

EMI shows up as chatter and reduces the low end, the minimum detectable signals. Ground causes overload or makes GB difficult and the reduction is on the high end, large/shallow target overload.

The signal is coming off the preamp or the first stage so try to keep it around 20% . I would go no more than 30-40%. If you are hunting in a clean area with only deep targets, then run the gain just below the overload point for max depth. But if there are a lot of shallow targets, then this will result in a lot of audio overload signals which might be annoying. The bottom line is, with any coil, run the gain as high as you can for stable operation, just as you'd do with any detector.

 

[Ytcoinshooter]

This where I need some clarification. The owners guide states that in the sensitivity zoom window that "signal %" = not returning from ground.
I would think the less % of signal loss the better. So I am trying to understand what you mean about if it is less than 20% you told Sonny1965 to send the coil in to you...? I've got to be missing something. As soon as time allows I am going to check my coils at the gain of 15, and sens/zoom to see what they read. Do I first try and ground balance...? As the high a gain might interfere with getting a good ground balance. I hav a V rated 12", stock 10"DD, non V rate 5.3" & 6x10".
Work gets in the way so I'm definitely going outside this weekend in the back yard to try them all.
Hopefully all quiet @15 gain holding it n the air will mean the null is good / coil optimum for use on the V3i.
Darn, I feel like a newby all over again. Well there was no Internet as we know it when I started, just the government and university ARPANET packet switching and text based. Nice to be where we are in technology!
Thank you, I do appreciate the help to digest this.

 

[Rob (IL)]

If a D2 coil at RX 15 in the air is showing less than 20% and not overloading it a very nice coil with a pretty good null. Asking him to send it to me was a joke. If at RX15 a coil had 0% signal it would be an absolutely perfect null on the coil. It it showed 10% it would be less perfect and at 20% less perfect as far a null. Now here is the important part, [size=large]they would all give you the same performance[/size]. All this is telling you about the coil is how much headroom you have for a signal before the coil overloads. No overload you are fine.

 

[Ytcoinshooter]

AH THANK YOU!!! I get it....just came in from the cold checking out my D2. It is well within the parameters you describe. I am not an "early adopter" of most any technology. Perferring to let things shake out with new devices (and software) before I purchase anything. Knowing the basic platform of this whites detector is from 2009 I felt pretty confident buying now as I believe mine was built in July '11.
Sorry I didn't get the imbedded humor in your reply to Sonny1965, I'm so intent on learning that I forgot to loosen up ) Thanks again.

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The sword plate here is one if my favorite keepers and was found deep in an old house yard with my XLT. CT has all kinds of surprises.

 

[Rob (IL)]

The detectors never had a problem. There were some coil problems early.