SAMPLE PULSE WIDTH QUESTION

[daverave]

what is the best sample pulse width for good depth on small and medium gold rings ????

[kt315]

sorry Dave my english is not so emotional rich spectruly to say you more. try to find out the copy ITMD.
seems nobody wishes to answer on your simple request here but you have to decrease sample pulse width and find out optimal value for your aim.

yours sincerely
Anatloy

[daverave]

hi kt315...thanks for your reply to me !!!! i know very little about delay pulse width and auto tune speed and im just experimenting to see if i can improve my detectors to low conductive items...gives my brain something to think about !!!!! where i live most of the best items are deep and i need something that go deeper cause the detectors ive already made are good on coins but not so good on gold items !!!! people with etracs and dual fields are finding nice items but me just coins and trash items.

[Silver Dollar]

Small gold is hard to see. The biggest limit is how fast after TX can you sample?
8 - 10 us would be a good range. Smaller TX widths are OK (50 us?) and smaller
sample pulses (10us?).

The autotune throws a monkey wrench into the mix as it reduces depth in trying to
balance out the ground. I'd guess slower would be better there as it would let you
see the target before "balancing" it out...

[daverave]

on the beach where i search i dont think 10 us delay would work cause of ground effect...a detectorist i know uses a whites dual field and does well but the machine not that stable...he tried my home made detector set at 25 us delay and he said it was more stable !!! what i really want to know is the optimum sample width (not delay) for gold items. With the variable resistor for the auto tune speed what resistance would give slower response as used in the hammerhead pi which uses a 1 mega ohm preset ????

[Davor]

585 gold has 1/10 conductivity of copper, and that should put gold rings tau in ~15us range. 25us of delay seem reasonable enough.

[6666]

optimum sample width

Try 25uS

[daverave]

i will try at the 25 us setting.

[Carl-NC]

Dave, a 15us delay usually works well in salt, and most beach PI machines use around a 10us sample width. Often a smaller sample width reduces target response and a larger width increases EMI noise. The pulse rate and sample width both factor in to how the sampling integrator is designed so it's not so easy to say "just use such-and-such."

[daverave]

i see there is more to this than i thought...i guess getting all these parameters correct is what counts to get good proformance with less EMI noise !!!!! im trying to learn but there is so much to get right in making a good detector i can see now !!!!