Hi Jim. I hunt adobe sites here in CA, whenever I can find them. Have done good around some of them. In my part of CA, any time we can find where an adobe was, is usually pre-1850s, as that was a method of construction favored during the Spanish/Mexican period here (before state-hood). But in New Mexico, if I'm not mistaken, there is .... EVEN TO THIS DAY .... places where people still build in this way. It's actually a good method, as long as the persons perpetually keep the walls plastered, and a roof on top, to keep moisture out. Ie.: it affords great insulation qualities, etc.... So how old is the particular adobe structure you're attempting to hunt?
And to answer your initial question, you're going to need to use some discrimination there, to *at least* knock out iron (unless you want to go crazy digging 1000 nails and iron stuff
) As for your getting good signals, I don't know what you're saying, when you say you dug it up and "my machine wasn't reading". Do you mean that the object no longer registered as a good target, once you got it out of the ground? Please expand on what you're trying to say, and maybe we can chime in to evaluate. Some things like cast-iron chunks, might give a good signal in the ground, yet of course, once out-of-the-ground and air-tested, will sound more like iron. There is audio-clues you can use to better evaluate what you want to pass, vs dig. What machine are you using?
Sounds to me like you need to get some practice first on an easy site (modern school yard grass, sand boxes, etc....) to better get the "sounds" down of various targets. THEN go try to tackle a relicky spot, full-of-iron, like this. Or another way is to hook up with someone proficient in your area (someone who routinely comes in with old coins), and have them accompany you. Have them flag targets that they believe are probable conductive targets trying to squeek through the ocean of iron. You go over it, and try to see/hear/isolate what they are showing you. Watch how they swing, and listen to what they're listening for (best if they're using the same machine as you, so all this is comparable). Conversely you show them targets you've flagged, and have them swing over them. And pay attention to their call. Eg.: "Iron false" or "pipe" or "yes I'd chase that" and so forth. Watch how they retreive targets, as that alone can be a determiner of frustration. I've gone out with newbies and watched them dig for 10 min. on a target, and give up in disgust. They ask me to check out their open hole, and the target was merely on the sides, yet they didn't have the pinpointing technique down. Or strange things like they were merely getting the corner of a building (where there had been a concealed copper framing in the corner), and the persons front edge of the coil was hearing that. The newbie figured there was a target there, and made a big hole for 20 min. It took me 10 seconds to scan the hole, and realize that all he was doing, was hearing the corner of the building, NOT something under the coil. These are all just examples, so don't get "lost in the example". Just trying to show that sometimes hooking up with someone proficient, and the "lights go on" immediately, rather than 50 hours of hard-knocks trial and error.
