A GREAT way to TEST & LEARN your machine.

[bigscoop]

The String & Sling Test Method

Similar to the Foster method but with the added advantage of wet sand and moving saltwater.

For this test you’ll need about 36” of limp string with a small sling attached to one end. You’ll also need a “shirt pocket” full of various sample targets. (I.e. a nickel, a small gold ring, a silver ring, a pull tab, a small piece of iron, dime, quarter, etc.)

First, take your machine to the beach at the water’s edge and I set the controls to achieve stable operation in 6” to 12” of moving water.

Now move back to the wet sand so you can lay your coil flat on the wet sand in one or two inches of moving water. At this point your machine is processing and filtering out the saturated sand and moving water just as it would be if you were actually hunting.

Now tilt the shaft of your machine slightly back so can swing the string and harness directly over the center of the coil.

Pick one of your test targets and place it in the sling at the end of the string and simply swing the target back and forth over the center of the coil. The response you get from your machine will be the same responses you’ll get when actually hunting in these conditions. What’s nice about this method is that you can do a lot of playing around with your settings while testing with various targets and studying the responses you get. You can also adjust the swing height of the test targets to better determine just how deep your machine is capable of reading them under your actual hunting conditions and the settings selected. Swing speeds can also be adjusted. And last, you can even move out to say, 12” of moving saltwater and conduct a series of the same test to see how much change the extra moving saltwater might make. I’ve spent quite a bit of time with my machines, especially the Excal so I’ll have a better understanding of the various responses, especially while in the all metal mode. If you’ve never tried this method I strongly recommend that you give it a try.
Scoop

 

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[search and recovery]

Sounds like a great way to test all your water machines. I will give it a try on some of the beaches I hunt. Of course it will be during the high tide. I can not miss my low tide hunting time. I would be interested in seeing your depth results from your beaches with the Excal to compare with the results I get on my beaches with comparable targets. You and OBN already have me researching the salinity seasonal effects on on my coils. Man! I love this hobby ( addiction ) !

 

[U.K. Brian]

Might work in the clean sand of Florida but on mineralised beaches its not an accurate method with a motion detector as the coil is not moving so is not affected by the ground (or in this case the beach).

 

[hamiddetecting]

Thank you

 

[search and recovery]

Seems to me, the coil does not know if it is moving, or if the object is moving and the coil is setting still. The coil will still null out (ground balance) the effects of the ground mineralization as the target is moved over it. The target is not nulled out because it is not stationary. So it should work just fine anywhere so long as ground balance has been achieved before you set the coil on the ocean floor. Just my opinion.

 

[bigscoop]

It's not a "perfect" system, nothing compares to what you learn during actual hunting hours. On the other hand, this is a good method because it introduces the effects of moving salt water & sand, i.e., the target actually has to be seen through the moving saltwater/sand particles/etc while the machine is actively processing/filtering all of these moving elements. So while it is true that the coil isn't moving, the elements are, which keeps the processor actively adjusting to changes in the environment. In my mind, as I applied it to my beach hunting, this is what was lacking with the Foster method.

 

[search and recovery]

That's the way I see it too, Bigscoop. Seems like a real world test on your machines depth capabilities on a section of beach that you actually hunt will tell you far more about what to actually expect out of your detectors true depth capeability. I am really interested in comparing my excal II with my DF, and my Sand Shark depth in the water this week at one of the beaches I hunt. I can see now I have got to keep a log of this kind of testing for different beaches at different times of the year. Keep things somewhat scientific so as to keep emotion and personal taste in what machine I prefer out of the results.

 

[bigscoop]

About the only major factor that is missed with this type of testing is, "user coil control" which in itself is a HUGE factor. especially as the sensitivity and coil size increases. For this reason, keep in mind that a machine that is running stable when the coil is stationary may not be as stable once the coil is in motion.

 

[search and recovery]

Good point. I have not tried a 15" WOT coil yet and hear from some of you guys how much harder it is to run stable even at reduced sensitivity. Although it is worth learning to use once the coil control issues are mastered. I will probably try one on my excal II after my warranty expires.

 

[bigscoop]

Good point. I have not tried a 15" WOT coil yet and hear from some of you guys how much harder it is to run stable even at reduced sensitivity. Although it is worth learning to use once the coil control issues are mastered. I will probably try one on my excal II after my warranty expires.

Just give yourself time to get use to the WOT....once you do "you'll absolutely love it!" If not, I know of at least two members on this forum who will quickly take it off your hands.

 

[search and recovery]

Thanks for the info bigscoop. So many of the oldtimers seem to like the big WOT coil that I think I will probably like it too. But not just yet. Got to master what I have first.

 

[U.K. Brian]

The ground/beach isn't moving only the target so results are slanted. Much better to use a test peg (if you can still buy one as dealers didn't really like to sell a product that showed so well how ineffective metal detectors are) or run a string marked in inches through a small disc of wood or plastic, secure well at the back. Then any ring can be dropped down the string on to the disc. The disc with added target is then sunk using a cut tube or just buried into almost liquid wet sand. Within minutes as the tide retreats the sand solidifies. As this is happening pull on the string until the exposed depth markings indicate the target is at the required depth. The "disc" levels up the target as its pulled upwards so you know that the maximum target area is being presented to the coil.