Testing and setting up the V3i--anybody else notice these?

[Calnevaroy]

Earlier this year, when the ground was still damp, I did some testing on my new V3i. Using a freshly buried coin I found the best responding filters for Best Data, Correlate and Single Frequency 2.5 kHz w/Non Normalized VDI's. While testing over freshly buried targets may not be the best way to adjust any machine, I used my results as a starting point for my ground conditions. Later, and most recently, I tested my filter selections on that same buried coin in my backyard only to find different filters responded better than my original selection---the ground was much drier now from the 90+ degree temperatures. Armed with this new information, I went in search of a deep target at one of my favorite old parks for further testing. Finding, what turned out to be a fairly deep copper memorial cent reading at a bit over 7", I re-tested, and again changed my filters based on best response. After this experience of testing, it seemed to me that the degree of ground moisture might dictate what filter might be best and to restrict testing to only found targets in the field, not freshly buried. Secondly, it seems that 2.5 kHz can be swept considerably slower than any of the multi frequency modes. I haven't tested either the 7.5 or the 22.5 kHz Single Frequency modes in this respect. In testing and comparing, I used the same settings and sensitivity for all modes. Any feedback is appreciated!

 

[Larry (IL)]

I haven't done that much testing, but the relationship between ground moisture and ground filters make sense. I run mine in the middle of the road so to speak, 7.5 and if I'm off by a little bit one way or the other, no biggie to me.

I know the right filter selection should clean up the audio response and target ID better. How much depth do you think is lost/gained by having the filters set wrong/right for ground conditions?

 

[Calnevaroy]

Quite a bit. At least that's what I've found by testing and running through all the filters, not once, but several times to make certain of my choice. I've found that the highest, I think the 12.5 Hz Band Pass filter, was the least sensitive, not responding at all to either the freshly buried coin or the 7" found copper penny. In damp ground, I originally went with the 5.0 Hz High Pass filter as it was by far and away the best responding filter of the bunch. I think this type of testing is best performed over a found, deep and many decades old buried coin. By the way, my ground is at least moderately mineralized here in Sacramento California. For those old enough to know, an old high frequency TR tuned with the coil on the ground would go full audio if the coil were lifted just an inch or two.