Friendly Metal Detecting Forums   Kellyco Metal Detectors
List all sponsors

Go Back   Friendly Metal Detecting Forums > Detectors and Gear > All About Detectors

Reply
  
Thread Tools Display Modes
  #1  
Old 01-12-2009, 10:32 AM
BrownTrout's Avatar
BrownTrout BrownTrout is offline
Full Member
 
Join Date: Dec 2008
Location: Bull Shoals, AR
Posts: 132
Default An Explanation Please

My Ace 250 has an LCD screen that runs the gamut from Iron on the far left to Silver $1 on the far right with Gold/Bronze, Foil, Pulltabs, Pennies and everything else in between.

I read where other MDs use a VDI rating, for example "87". Can someone correlate for me the VDI range relative to what appears on the screen of my Ace 250?

__________________
Garrett Ace 250
Nobody told me this would cause so many aches and pains!

Reply With Quote


  #2  
Old 01-12-2009, 11:26 AM
sectshun8's Avatar
sectshun8 sectshun8 is offline
Elite Member
 
Join Date: May 2008
Location: Golden, CO
Posts: 9,535
Default

Well not all machines have the same VDI... but lets say a dime signal on the ACE 250 would come up as a +36 on my X-Terra 30.

There's a post somewhere that has a diagram of what comes up under most of the ACE 250 notches.

__________________
Jimmy - Minelab X-Terra 30 | White's BHID300 | White's Spectrum XLT | Tesoro Compadre | Vibra-Probe 570 | Garrett Pro-Pointer
2012 Totals: 112 coins @ $10.04

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
|
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

US Army - OIF/OEF Vet

Reply With Quote


  #3  
Old 01-12-2009, 11:49 AM
BrownTrout's Avatar
BrownTrout BrownTrout is offline
Full Member
 
Join Date: Dec 2008
Location: Bull Shoals, AR
Posts: 132
Default

Thanks. That's a start!

__________________
Garrett Ace 250
Nobody told me this would cause so many aches and pains!

Reply With Quote


  #4  
Old 01-12-2009, 12:04 PM
Lowjiber's Avatar
Lowjiber Lowjiber is offline
Elite Member
 
Join Date: Jun 2008
Location: Henderson, Nevada
Posts: 5,955
Default

Just emailed a phase angle / VDI chart.

__________________
John Ace 250, Prizim III, F2, MXT, Vision, Surfmaster Pro, DP Wader

"There remains a finite number of straws that can be placed on a camel's back."

Reply With Quote


  #5  
Old 01-12-2009, 05:32 PM
Nortonics's Avatar
Nortonics Nortonics is offline
Elite Member
 
Join Date: Aug 2008
Location: Elk River, MN
Posts: 803
Default

A general chart from White's:



An interesting set of charts for the White's DFX - check the whole article here:

http://www.thebeepgoeson.com/display...e=DFX_VDI_Norm





__________________
Tom.

Fisher F75 LTD2 w/ Sun Ray Invader FX-1 - Fisher CZ-5 w/ Sun Ray Invader FZ-1 - Garrett Grand Master Hunter CXII - White's Surfmaster

Reply With Quote


  #6  
Old 01-12-2009, 07:12 PM
BrownTrout's Avatar
BrownTrout BrownTrout is offline
Full Member
 
Join Date: Dec 2008
Location: Bull Shoals, AR
Posts: 132
Default

Impressive responses from those with a lot more experience than me on this board.

My thanks everyone!

__________________
Garrett Ace 250
Nobody told me this would cause so many aches and pains!

Reply With Quote


  #7  
Old 01-12-2009, 08:18 PM
Rudy's Avatar
Rudy Rudy is offline
Administrator
 
Join Date: Jan 2006
Location: Beaumont, CA
Posts: 24,960
Default Understanding VDI in Depth

WARNING, not for the faint of heart.

For those that want a more complete understanding of the underlying principle behind VDI, read on.
Everyone else can skip this post.

Detector discrimination and consequentially VDI numbers as well, depend on the lag between the peak amplitude of the transmit waveform and the peak amplitude of the Eddy current induced in the target.

We normally, but incorrectly, refer to this as being based on the target's conductance. Thus you hear about targets being high or low conductors.

If you wanted to be picky about it, it is actually a measure of the target's admittance.

Admittance is a vector quantity (ie. it has a magnitude and a direction) made of two components: Conductance and Susceptance.

You can think of them as an east-west axis for the conductance part of the number and a north-south axis for the susceptance component.

Conductance is associated with the electrical resistance of the target to pass a DC current.

Susceptance is associated with the ability of the target to temporarily store and later release energy from the transmitter signal.

Both of these components make up the Admittance vector. It is the phase angle between the applied transmitter signal and the target's admittance vector that forms the basis of discrimination and VDI number.

Different manufacturers map this phase angle into an arbitrary number scale. On the White's machines this arbitrary scale goes from -95 to +95.

Silver and other "high conductors" have an admittance vector mostly determined by the conductance part, while in iron and other largely ferrous materials, the susceptance part dominates the admittance vector.

__________________
HH, Rudy

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.



The one lesson we've learned from history is that
we have not learned any of history's lessons.

Reply With Quote


  #8  
Old 01-15-2009, 08:32 PM
Shooter7Mustangok Shooter7Mustangok is offline
Junior Member
 
Join Date: Jun 2008
Location: Recntly moved to Oklahoma from Denver Colorado
Posts: 44
Default Ace sounds

If ya dont mind I'd like to add my 2 cents, I have had my 250 for almost 3 years. I dont pay much attention to the LCD unless its a steady belltone... what I'm saying is its not the display but the sound.. 95% of the time I'd bet the ranch on what I will dig.. everything has a different sound. I know it only has 7 tones but its the way the tones repeat thats the key. Like a penny has a different sound than a dime and a wheat has a different sound than a modern cent..and silver sounds like a "jackpot" dingdingdingding lol. Well thats my two bits.. good luck and happy hunting
Reply With Quote


  #9  
Old 01-19-2009, 10:51 AM
BrownTrout's Avatar
BrownTrout BrownTrout is offline
Full Member
 
Join Date: Dec 2008
Location: Bull Shoals, AR
Posts: 132
Default

I agree 100% with Shooter. I still glance at the LCD, basically to confirm my interpretation of the tone and to see the approx. depth. Only had the Ace 250 for a month now but I've learned more from the tones in the headphones than I have from the LCD Target IDs. Haven't found a wheat penny yet but certainly looking forward to hearing that tone!

__________________
Garrett Ace 250
Nobody told me this would cause so many aches and pains!

Reply With Quote


  #10  
Old 01-19-2009, 11:17 AM
UK Brian UK Brian is offline
Senior Member
 
Join Date: Jul 2007
Location: Wales
Posts: 299
Default

I agree with Shooter and Brown Trout. You never will do well accepting VDI information. The difference on the same coin between New York and Arizona was between 8 and 10 when I tried it last year.

__________________
2 Nautilus,Fieldmaster, 2 Xp's, 3 Pulse, Ixcis Diver, 2 Arado's,Quadtone, Treasure Baron,Shadow X5 Minelab Sov., Whites Spectrum, Hoard Hunter, Beach Hunter I.D., Spectra V3

Reply With Quote


  #11  
Old 01-24-2009, 06:45 PM
rascal's Avatar
rascal rascal is offline
Elite Member
 
Join Date: Nov 2008
Location: Florida
Posts: 1,915
Default

These posts have great information in them, Thanks

__________________
rascal: detectors I use> Excalibur 2, Sov. GT. SE

Reply With Quote


  #12  
Old 01-24-2009, 06:55 PM
Lowjiber's Avatar
Lowjiber Lowjiber is offline
Elite Member
 
Join Date: Jun 2008
Location: Henderson, Nevada
Posts: 5,955
Default

Originally Posted by Rudy View post
WARNING, not for the faint of heart.

For those that want a more complete understanding of the underlying principle behind VDI, read on.
Everyone else can skip this post.
Very Nice!!! Thank You.

(That went directly into my "The World According to Rudy" file.)

__________________
John Ace 250, Prizim III, F2, MXT, Vision, Surfmaster Pro, DP Wader

"There remains a finite number of straws that can be placed on a camel's back."

Reply With Quote


  #13  
Old 01-24-2009, 07:49 PM
cliff490's Avatar
cliff490 cliff490 is offline
Supporter
 
Join Date: Aug 2007
Location: South Central South Dakota
Posts: 522
Default

Originally Posted by BrownTrout View post
My Ace 250 has an LCD screen that runs the gamut from Iron on the far left to Silver $1 on the far right with Gold/Bronze, Foil, Pulltabs, Pennies and everything else in between.

I read where other MDs use a VDI rating, for example "87". Can someone correlate for me the VDI range relative to what appears on the screen of my Ace 250?
Maybe this is what you are looking for

Name:  Ace%20250.JPG
Views: 1909
Size:  45.2 KB
Reply With Quote


  #14  
Old 01-24-2009, 08:10 PM
Rudy's Avatar
Rudy Rudy is offline
Administrator
 
Join Date: Jan 2006
Location: Beaumont, CA
Posts: 24,960
Default

Originally Posted by Lowjiber View post
Very Nice!!! Thank You.

(That went directly into my "The World According to Rudy" file.)

Thanks John. That file must be getting to be about as large as a can of tuna by now.

__________________
HH, Rudy

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.



The one lesson we've learned from history is that
we have not learned any of history's lessons.

Reply With Quote


  #15  
Old 01-24-2009, 10:57 PM
CyberSage's Avatar
CyberSage CyberSage is offline
Elite Member
 
Join Date: Sep 2006
Location: Fort Collins, Colorado
Posts: 2,105
Default

Originally Posted by UK Brian View post
I agree with Shooter and Brown Trout. You never will do well accepting VDI information. The difference on the same coin between New York and Arizona was between 8 and 10 when I tried it last year.
Most of us do not have such a broad range of hunting areas. The graphical output on the DFX is actually very reliable and accurate within a given area. The MXT is even more repeatable. Use of extreme words like "Never" in your above statement would suggest a bias toward tone hunting. I for one Like all the information I can get about a potential target. American Coins are very uniform in size and composition. I can see where this would not be true for a hammered coin. I prefer tone to visual response as well, but the VDI output can be valuable information.

Keep Swing'in
Jack

__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


Last edited by CyberSage; 01-24-2009 at 11:01 PM.
Reply With Quote


  #16  
Old 01-26-2009, 10:50 AM
Detector's Avatar
Detector Detector is offline
Supporter
 
Join Date: Jan 2006
Location: Dodge City KS
Posts: 9,421
Default

I'm with CyberSage. To suggest that "You never will do well accepting VDI information" is just plain wrong. The VDI is a valuable tool. Used incorrectly, and it will do you no good. Used properly, and it is a great asset. Anyone that has, and uses, the VDI will know just how wrong that statement is.

I use the VDI information on every hunt and I do quite well.

__________________
The real treasure is in the hunt....

Reply With Quote


  #17  
Old 01-26-2009, 11:17 AM
Nortonics's Avatar
Nortonics Nortonics is offline
Elite Member
 
Join Date: Aug 2008
Location: Elk River, MN
Posts: 803
Default

Originally Posted by cliff490 View post
Maybe this is what you are looking for

Attachment 28601
Regardless of whether that attachment helps, nicely done Cliff!

__________________
Tom.

Fisher F75 LTD2 w/ Sun Ray Invader FX-1 - Fisher CZ-5 w/ Sun Ray Invader FZ-1 - Garrett Grand Master Hunter CXII - White's Surfmaster

Reply With Quote


Reply


Thread Tools
Display Modes

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Ace250 LCD Visual Explanation ToddB64 How to Use Your Metal Detector 67 03-07-2018 10:14 AM
Explanation would be helpful Scubacat Beach and Water Hunting 5 09-02-2010 05:44 PM
Explanation of Pinpointing? BRJ123 How to Use Your Metal Detector 4 05-24-2008 02:51 PM
For you coinshooters out there a better explanation of Per Coin Value> DFX-Gregg What's the Value? 17 07-15-2007 12:31 AM


All times are GMT -4. The time now is 03:17 AM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2018, vBulletin Solutions, Inc.