Question for you diggers out there

J

jimmyk

Established Users
I started metal detecting in 1979. One of the things I was told early on was how much better a signal you got when the ground had moisture in it. It enhanced the "halo effect" and made it easier to hear targets. Conversely, bone dry ground made it hard to hear the deeper signals because you didn't' have the advantage of the enhanced halo effect. I never really hunted in seriously dry ground because of that advice. I always waited until we got some rain. That was until this year. This year has been unusually dry. Little moisture, even during the Winter and Spring, so the Summer time ground was especially dry. I've been hunting this camp when ever possible all year. I use a White's MST with a 12" Hot Shot coil. I've had real good luck with it, even in the dry ground. In the back of my mind I kept thinking this outfit would absolutely rock when we finally would get some rain. Last weekend we got five inches of rain and I was ready to take advantage of the halo effect. I hunted two days this week with some very interesting results. I found bullets, but was surprised that the all metal signals were significantly harder to hear, even with the now wet, easily dig able ground. I was hearing the discrimination just as well, but the all metal signals were faint. I puzzled over this as the hunting went on for the two days and finally came to a conclusion. My question is if this is an anomaly with the unit I'm using, or does it apply across the board to all detectors. Here's my conclusions. It is true the halo effect is enhanced by moisture in the ground, but the effects of the mineralization in the ground is enhanced, as well. I found I was unable to run my sensitivity as high in wet ground as in dry ground. I had to back off between 10 and 20 percent. Consequently, I was losing signal strength on deep signals. In dry ground I was getting a large, solid all metal signal, but in wet ground I was getting fainter, smaller signals, due to the inability to take advantage of the increased sensitivity. As a result, I was hearing better all metal signals in dry ground. The discrimination signal didn't seem to be effected much at all, as far I I could tell. I'm guessing this is a situation that is brand specific to my MXT. I say that because last week a hunting buddy of mine joined me for a day of hunting in the dry conditions. He is running an Explorer II which, by many is considered one of the deepest machines around. I was intimidated and fearful that he would come in to my camp and clean up with his vaunted Explorer. End of the day results were that I had dug 44 bullets and he dug ZERO. He's had the machine for nine months and has had good success with it. But in the dry ground it was useless. I put him on to at least a half a dozen targets I was confident were deep bullets and he was unable to read any of them. The next day I was on the Minelab Owners Forum and came across a post that said it was generally known that the multi frequency machines (the Explorer) didn't work as well in dry conditions as the single frequency machines. I thought to myself, "No s---, Sherlock" What is your experience with your favorite relic machines?

Thanks for viewing my rant. It was an eye opening experience for me. Now I can't wait for things to "dry out'. Go figure.

Keep on diggin'

jimmyk in Missouri
 
I've been detecting since 1968 and have heard the same theories about the halo effect. But I've detected when I could,wet or dry,and haven't seen that much difference in coin hunting success.The last article I read discussed the halo effect on ferrous and nonferrous metals.The author suggested that iron,and to a lesser extent copper release oxidation into the soil around the target,increasing their "target size".He said that silver and gold do not oxidize to any extent,so no halo effect.The silver is highly conductive and gives a good signal in all conditions.Now I'm going to pay attention in the future and see how mineralization effects change with the amount of moisture in the soil.The soil conditions in Idaho are generally mild with low mineralization,so it might make little difference here.
 
I can say iron probably has a significant halo effect. I dug very few nails with dry ground, but dug many more when the ground was wet. Made it harder to discriminate them out. Gave many more iffy signals you had to dig when going after those deep signals. The ground here in Missouri seems to be moderately mineralized.

Thanks for your input.

Jimmyk in Missouri
 
Moisture in the ground has very little affect on the operation of any metal detector. Most metalic items in moist soil will start to corrode. As they break down they create a halo of super mineralized soil around the given item. The so called halo effect makes the target appear bigger to your metal detector. Because some targets corrode faster like iron, and other ferrous metals, these will give a halo effect where as gold does not corrode, and silver, copper and brass will at a slower pace than iron. Moreover, while the halo effect may work for some metals it will not for others. :D
 
Canewrap is right on the money. More in depth research needs to be done so this inigma can be put to rest. Until such time, keep digging!!! :lol:
 
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