Pinpointing a Sov

[Art (NWOH)]

The basic problem with pinpointing a Sov is...
Failure to understand that this is a motion detector ONLY. It does not have a no motion pinpoint.

SOUND AND MOTION !!!!
Control the coil movement as you listen to the audio. Watch how the coil is moving over the ground.
You must control the speed, width, and center point of the sweep....while listening.

First poor drawing shows the relationship between the coil motion, sweep width, audio, and position of the target when the target is to the right of the sweep center. Reverse the drawing for how it works with the target to the left of the center of the sweep.
Note that the peak audio does NOT occur when the coil is centered on the target.

The second pic shows what happens when the sweep is the right width AND centered over the target.
Note that the audio rolls up on either side of center equally . The target is in the 'valley' between the audio peaks.
You do not need to reach the peak in audio with your sweep width...You only need to control the sweep to get the audio to roll up equally on the left and right sides of the sweep.

How you want to finish the pinpoint is up to you.....By the 'X' method or off the tip. Or work the coil forward and back while keeping the audio centered up to determine when you have it right under the center.

Some coils may not pinpoint exactly center. They may be consistently be off a little in some direction. You have to learn the coil.

Hope this helps.
HH

 

[matthias]

Thanks Art... great explanation and pictures.

 

[Art (NWOH)]

Pictures can help a lot when you don't have a video , or can't stand there and watch in person.
The inter-relationship between sound, motion, and target position are about impossible to describe with words alone.
You still have to get used to the feel of it. It's difficult at first, but you get used to it very easily. Just like reaching for a cup of coffee. You don't think about the different motions involved...but you get coordinated and do it right without spilling the cup. If you can see your hand and the cup the required motion becomes instinctive. Let your eyes, ears, and wrist control work together.

I could have also compared this to pinpointing in an all motion discriminate mode with a detector that 'beeps'. Eyeball the spot between the beeps.

To make things hard...extend the rod as far as possible, hang the biggest heaviest coil you can find on the end , and swing like a maniac. You get no coil control, can't pinpoint or check out targets worth a crap.

I find that keeping the rod short enough to let the coil hang just off the ground right in front of my feet gives me the best control. Your brain gets to start controlling coil position, sweep speed, and sweep width automaticaly after a short time. Motion is not forced. It is more like adding just enough wrist to keep a narrow pendulum motion controlled.

HH

 

[Critterhunter]

Printing this out to read. Looks informative. Thanks.