Need help adjusting for very bad ground?

[Downdeep]

Hunted an area today that apparently had very bad ground. Two harvested corn fields, one across the street from the other. Field one I had been buzzing along with no issues and even had tx boost on. Picked up and dug a few targets that were easily in the 6-8" range, though they weren't what I was looking for. Crossed the road and up a hill and noticed that any time my coil touched the ground, I got an overload signal. So, turned off tx boost, and tried again. Better.. but, I hunted a while with a very slightly unstable machine, though not bad enough to bother me. Then I saw a piece of can slaw laying on the surface. Do to the corn stubble at this particular spot, I had swung roughly 3" above it and got NO reading. Our of curiosity, I took a 30 caliber bullet out of my bag that I had found at the other field and laid it down. Barely got a reading in the mid 50's while 2 inches above it. Air tested the bullet and got what I would expect. High 50's VDI and about 10" from the coil. Then I buried that same bullet about 2" underground and got nothing, no reading, it cut out when I swung over it.

I tried ALL ground filter settings and swing speeds. I lowered my gain from 15 to 4 testing every two numbers on the way, no luck. Tried different transmit frequencies including the 3 freq setting, no luck. Had reground balanced the machine in several different areas. Turned off and on again, still nothing.

I was using a custom relic program that works well for me in just about any other area. The settings below were basically what I had started with and had performed beautifully across the road.

7.5 transmit frequency
ground filter 7.5 band.
gain at 15
AM sens. 75
Disc sens. 85
accepted vdi's down to -20
recovery delay 80
auto trac on

any thoughts or suggestions?

 

[Larry (IL)]

I sounds like you have tried everything I would have tried. I have heard that a heavily or newly fertilized field is almost impossible to hunt due to the extreme alkali conditions. Do you think this could be a possibility?

 

[Downdeep]

Its been in corn for the past 2 years, but don't know about the fertilizing other than that they spread chicken poo on it. But that goes for both fields. The fields have sat untouched since corn was harvested, regardless. Thinking back, I've always had problems with this particular field, and am guessing that the several inches of rain at the end of last week has made it much more wet than usual.

 

[Downdeep]

Just did a quick google search and found that chicken manure, particularly hen manure, raises the PH value substantially. The poo in this area comes from an egg laying plant up the road. I would assume that both fields had the same application, so in theory something else may have come in to play to worsen the problem in field 2. Possibly the mineralization on the hill was more significant and in combination with the PH value, cause severe issues. Plausible?

 

[yazoo]

Heard somewhere that the salt mode was of some help with fertilizers.Is under tracking and soil type I believe. Yazoo

 

[Downdeep]

I will definitely keep that in mind and try it next time there. Which may be tomorrow

 

[Larry (IL)]

Very plausible. Some ground can not be hunted with a VLF detector and you would have to go to a Pulse detector.

 

[kyledfx]

like yazoo said try salt ground salt compensate and correlate 3 freq. salt without it wraps a surface quarter in my beach area try 3 freq salt correlate span40 wrap -90 10 high filter . good luck!

 

[Rob (IL)]

Try the salt compensate, and salt soil. This works in heavily fertilized parks and lawns.

 

[Downdeep]

Thanks for the suggestions everyone, I'll give it a try.