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Hertz/target seperation
Posted by: Herb Jones
Date: December 18, 2017 09:51AM
Does the frequency of a machine influence target separation? Do lower frequency machines tend to separate targets better than Higher Frequency machines? Has anyone ever noticed anything like this?

Re: Hertz/target seperation
Posted by: Mega
Date: December 18, 2017 11:49AM
For me its the coil size and recovery speed rather than the khz,if i am on a really trashy site and i want the best target separation then i use a much smaller coil than stock that then allows me to stand a far better chance of picking out the decent desirable targets from the trash,on some really bad roman or saxon sites then i would use a very small 5'' coil on my T2 or a NEL Snake 6.5''x3.5'' or i even use my 4'' coil on a old Tesoro based detector.

If you have just say one 13khz detector then you dont have alot of say in the matter really,but you can make it into a deadly machine with terrific target separation just by placing a much much smaller coil on and it will perform great rather than using a stock or larger coil on which will/can cause target 'nulling'.



A stick with a plastic ring at one end and an eternal optimist at the other!

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Re: Hertz/target seperation
Posted by: mrwilburino
Date: December 18, 2017 03:36PM
On the Deus, using four different frequencies with the same coil, the highest frequency gives the best target separation; and vice versa for the lowest frequency. Lots of factors involved, but seems like the higher frequency machines are the better target separators.



Fisher Teknetics XP Minelab

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I tend to agree with Mega on separation
Posted by: vlad
Date: December 19, 2017 02:14AM
I think recovery speed is of most import followed by loop size, and type (with some judicious use of gain and sensitivity.)
Frequency does have an important part in some aspects; both the ground effect & wet salt effects can be decreased or increased depending on frequency (George Payne has stated
that those things are diminished to the point of no effect the closer they are to 0.)
Frequency cannot be downplayed in target response either; it is not chance that detectors used for gold are at higher frequencies or copper and silver at lower; general purpose units at one
frequency are at best a compromise.
An example of a specific frequency on select targets can be demonstrated by the 100kHz units (Compass 77b) which do not respond to smaller iron, like nails and will pick up conductive objects among them.
https://www.youtube.com/watch?v=cXxhIVZIrpg

Also don't forget ......
Posted by: Tom_in_CA
Date: December 19, 2017 09:47AM
I liked mrwilburino, mega, and vlad's inputs. I would add that: It's not only target separation to be questioned for the higher vs lower frequency question. It's also a function of averaging (aka see-through). So for example: "separation" is fine and dandy if there is a peek at the target . But let's say the top target is a nail, and let's say it's perfectly on top of the coin. Then would you mask ? Or would the targets be averaged on the TID, such that you could get a hint that something conductive is underneath ?

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