sweep rate

[William1221]

I being a beginner too I have a question abt sweep rate If you took a nickle and placed it 6 to 8 inches in the sand and swept your coil across it Is there a way to tell if the swing rate is the correct for the detector and the coil size?

 

[UK Brian]

P.I.'s are not as sensitive to sweep rate as non P.I. motion machines but with any new machine it always pays to see the effects of a different sweep speed not just from the point of depth improvement but to see if there's any target I.D. benefit.
Unfortunately you can't have a definitive answer as there's so many types of machines and coils and the different ground minerals.
I make a point of checking the first deep signal or two on a new site with slower and faster sweeps than normal just in case it makes a difference.
P.I.'s with stock coils are easy going whereas with "normal" motion machines its very important to relate the filtering and coil size and sweep accordingly.

 

[Reg]

Hi William,

Brian has pretty well touched on all the key areas and what to expect or not expect. I will add that the only best way to tell what is the best sweep speed is to simply practice and try it.

As Brian says, detectors vary in design and as such, the ideal sweep speeds are more of a function of the design engineer's preference, so it is possible to have one work better at faster rates while another work better with a nice slow sweep rate.

This question also sort of falls in line with the one about PPS and is also dependent upon the filtering used inside the detector. Heavy filtering will require a slower sweep speed for the best results.

As for PI speeds versus VLF's, part of the reason for the difference is the coil design. VLF's have to use a DD type or a concentric design, which effectively narrows the detection field of view of the coil. A PI can use a mono coil which basically widens that field of view, thus making it easier in some aspects. Generally speaking a DD coil has a very narrow detection zone so a fast sweep can be detrimental, but again, this is also dependent upon the filter design also.

So, there is no set answer to your question. That is why experimenting and practice become so important. At least, in my opinion, it does.

Reg