sand shark pulse rate

[calibil]

The regular pulse rate of 600 pps (pulses per second) is the normal setting but what can It be set to? The manual just say (wider)

 

[tvr]

The pulse rate stays the same. The time from the start of one pulse to the start of the next one is the same, but the width of the pulse can be changed. Something like shown below with the top one having a shorter pulse width and the bottom one having a longer pulse width. I don't have any idea what the pulse width ranges are on the Sand Shark.

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[calibil]

Okay thanks, got that concept but what is the advantage to that ? better depth? does the expanded range have more or less sensitivity to the same size target (nickle) @ 4in, nickle @ 8in
I understand the pulse machines read the receive decay signal and software calculates that info , is there a layman's explanation for what the pulse width change can accomplish for beach hunting, type target, depth etc.. The manual is vary minimal on this subject.

 

[tvr]

calibil,
Power transmitted is related to the peak power multiplied by the duty factor. The duty factor is the pulse width divided by the pulse interval.

So with a constant peak power and a fixed pulse interval (or rate) as the pulse width is increased, the duty factor is increased and more power is transmitted.

I searched the findmall PI forum and a different technical forum for information on how increased power may affect the sampling of the residual eddy current and did not see anything pop up that showed a correlation to changes in sensitivity as power changed versus conductivity of the target. So, I'd guess that more power might add a little depth as well as use more battery. I did see references to sensitivity to target conductivity shown to vary based on changing the delay of sampling time from the end of the transmit pulse. The delay time also affected stability so there were limits of useful delay ranges. The Sand Shark does not have a variable delay.

My experience with the Sand Shark has been that, with some hunts run at full pulse width and some at the recommended preset, I did not notice a significant change in the depth I think I was digging on deep targets. It is a little hard to tell since the wet sand falls in and target sizes, corrosion, orientation and what the actual sand conditions are probably all affect detection depth. I suspect how well I am listening may affect detection depth even more.
tvr

 

[calibil]

Thanks for the detailed reply, I guess it may not always be worth it to crank up the juice (pulse) and burn through batteries.
The ML(4500-5000) & Whites (TDI) have a pulse delay control (with which I am familiar) so I just wanted to know if the pulse adjust was similar on the S.S now I know "SUPER GOOD" and happy hunting