Tried something new today (Bryce, don't read this! ;) )...

[sgoss66]

In the town I live in, some research has revealed that one of our relatively modern city parks was built by the city after acquiring (with grant money) several original homes in a very old portion of town, removing them, and then building the park on this parcel of land (used to be four city lots, I believe). I had overlooked this park in the past due to its "young" age, and expect that at least some other detectorists have, too. But, knowing now how the city acquired the park, I thought that this would possibly be a potentially very good spot.

Well, I immediately ran into "problems." As you might expect where four roughly 100 year-old homes were removed by city crews, this park is LITTERED -- absolutely LITTERED -- with a layer of ferrous trash -- bits of nails, and all manner of other small iron. I literally had a near continuous threshold null. While many folks, including Bryce, have said that they have full confidence in these machines to signal a good target THROUGH a dead null, I simply cannot get past the unnerving feeling of hunting in a constant null. BUT, having said that, I know this park has some goodies hidden in it.

So, I opened up the screen completely from IM 22 to all-metals. But, after about one minute of an absolute barrage of high tones, I did something controversial -- I switched to ferrous sounds. I feel like I was breaking a cardinal rule doing so, but I simply cannot deal mentally with constant dead nulling of the threshold. I only had 1/2 hour left to hunt, but I immediately felt comfortable. My threshold returned, and I was getting a CONSTANT barrage of low tones, which was COMPLETELY manageable for my brain. The constant low tones were almost like a "threshold" of their own -- and any time I heard any peep that was different (higher pitch) than the constant drone of low-toned iron hits, I stopped to investigate. This was, in my opinion, a TERRIFIC way to hunt this specific type of site. I hit four low ferrous (high pitch) targets in about twenty minutes, one was a key to a lock, one was a bent rusty nail (it tricked me -- just like they do in conductive tones!), one was a mason jar lid, and the last one was a wheat penny. I am almost certain I would NOT have found that wheatie hunting in conductive sounds, IM 22, and dead nulling. I made a mistake, in that after I left I remembered that I should have switched back to IM 22 and conductive sounds when I hit that target, and checked to see if I would have found it. I will do this type of testing the next time I go to this site. But for now, I feel MUCH more confident that I can hit on the keepers more effectively in this specific type of site, than I could in IM 22 and conductive sounds. I don't like hunting this way as well as putting it in conductive in a lower trash area, and listening for that sweet silver sound, but in a site like this, I really feel like this might be a great way to hunt for some folks.

Sorry if I am stirring up a debate here, but for me, this was a welcome relief on a site where my alternative is a constant, dead nulling of my threshold.

I'll report back in this thread the next time I hunt this site, and will check some targets (that I find in AM/ferrous sounds) in IM 22/conductive sounds, and see if there are any that I can hear in AM/ferrous that I could NOT hear through the threshold null in IM 22/conductive.

Steve

 

[ohio fred]

n/t

 

[Larry (IL)]

There is nothing wrong with Ferrous mode, it works for me.

 

[MNCoinhunter]

There is no written rule on how you should run your detector. Yesterday I got a weak, but good-sounding signal. So I briefly switched to manual sensitivity and was surprised at how clear the signal became. When I switched back to auto the signal disappeared. Talk about frustrating. It ended up being a rusty nail, but I began to wonder how many other targets I was missing. I did'nt dwell on the issue though. I just went back to auto and kept going. Maybe the next time I get up there I will run in manual for the day and see what else turns up.

 

[Hotcz70]

Nothing wrong at all in switching to ferrous sounds and running all metal. A lot of people do well with it.

I just prefer the nulling of conductive/IM over the barrage of sounds when hunting in AM.

We all have to do what works best for us.

I am able to pick out coins in iron when my machine is in a dead null....and have personally never located a coin in ferrous/AM that I could not still pick out in conductive/IM...but I have spent a lot of time learning this method and training my ears what to listen for.

Someone else might not "hear" what I hear and therefor feel ferrous/AM allows then to hear more good targets. It's all a matter of personal preference and what works for each of us.

 

[sgoss66]

An update:

Went back to that same site this morning for a very short hunt. At one point I hit what I thought was a good target, and I did remember to check it in both conductive and ferrous. I heard it in both. Turned out to be a wheatie.

Then, after reading this thread, up through Bryce's comments, I hit my test garden today. I wanted to see for myself (I'm hard-headed, Bryce!) what effect "nulling" would have on my machines ability to "see" known targets. However, I "sanitized" my garden before burying the coins, so the only way I could get my machine into a null is to run super hot sensitivity. SO, that's what I did. First, I ran in semi-auto sensitivity, conductive sounds, and located what were just short of "fringe" depth coins. In other words, diggable hits, but any deeper and they would not have been. I then ran sensitivity all the way up to 32 manual, so that I could get my machine to go into a threshold null. Then, sweeping back over the near fringe-depth coins, I found out that these coins WOULD break through the threshold and give me a tone. SO, Bryce, your thoughts about "it's a matter of what works best" make sense. The coins did reveal their presence "through the null." You have always said that you have complete faith that your machine will, running IM 22 and conductive sounds, hint at coins even in a dead null. Even knowing that the machine CAN see coins through the null, it's simply difficult, and unnerving, when I haven't heard a threshold for minutes at a time. On the other hand, I seem to trust my machine more in an iron-infested site listening to all that iron "grunting," and keeping my ears tuned for any hit that is NOT part of the machine-gunning low tones. I think the bottom line is, whatever gives each person the most confidence in their machine, is worth trying. But, having said that, I do believe that the truth is this: if the machine can "see" a target through the iron, it will signal that target to you -- either as a high tone hint through the grunting (if running ferrous sounds and all-metals), or as a high tone squeaking through the null (if running conductive sounds and IM or disc.) Either way, I think, will work. That's one of the cool things about these machines -- lots of ways to set them up!

Oh -- McDave -- interesting idea there, hitting a site once with super high sensitivity just to see if you turn up anything different. Good idea!

Steve

 

[dewcon4414]

If there is promise i hit a site in several ways to milk it. Open screen cond and ferr are options i use. If you are in a trashy area i find RUST just as much a problem hitting in the lower right bottom of the screen with a high pitch. But i like the sound of coppers.... a reason i use it in field hunting. No right or wrong and ive learned to hunt in a variety of ways.

Dew

 

[Frase44NY]

I hunt the same way..most of the sites i hunt are full of iron..Iron is GOOD..means old stuff!! I also feel uncomfortable with the nulls, and dont mind the low tones as much. I tried Bryces setup, but it didnt work for me at my sites. It obviously works for him by the finds hes making. The only time I switch to conduct really is when overwelmed by crown caps. I think you have to set up your machine according to sites that you hunt.

 

[Frase44NY]

well let me ask you this. By causing your machine to null by using high sens, would it simulate a rusty nail type of null? the reason i ask is because that rusty nail can really tie up the processor on these machines. It really holds on to the audio and can cause you to miss a close keeper..conduct or ferrous??..hmmm..good topic

 

[sgoss66]

Frase --

You bring up a good point with the "high sensitivity" null versus the "big piece/pieces of iron" null. No, I would guess they are not the same. In my mind, the reason is this -- it's a "stregth of signal" issue. Obviously, iron MASKING is a real thing -- iron sends such a strong signal back to the machine that it easily "overshadows" nearby nonferrous targets very effectively. During any times where your machine is NULLING due to iron, in my mind that is a hint that iron MASKING is a potential problem at that moment. Now, if your machine is nulling strictly due to running high sensitivity (in irony-type clay, for instance), that nulling of the threshold is being caused by the soil matrix's iron content. While ground balance is supposed to "take care of" much of this iron signal from the soil, my understanding is that at high sensitivity some of this iron signal sort of "leaks" through to the machine -- and causes a response. Comparably, however, I'd think a coin-type target would in this case be a strong enough signal that the machine would easily see it -- and thus this target should easily "break" the "ground matrix-induced" nulling. Now on the other hand, a big rusty nail causing the nulling is a much more substantial iron target, and thus the potential for masking is much higher. Therefore, this much stronger iron signal would be more likely to "overwhelm" the signal from a coin-type target -- and thus it is much harder to "break the null."

Obviously, though, non-ferrous targets are often PARTIALLY iron masked, and it is THESE ones we we hope to find, and these ones that we are hoping will "break" the null. If a target is TOTALLY masked, obviously, you will NOT see it no matter how your machine is set up -- that's the definition of "totally masked." A totally masked target obviously will NEITHER "break the null," when running your machine with some disc. or iron mask, NOR will it sound off as a high tone if you are running an open screen/AM and ferrous sounds. That target it simply un-detectable (until and unless the "masking" piece of iron is removed), so your machine would obviously not "see" the target no matter how you set it up.

This is a complex subject, and I am trying to wrap my brain around it. I think though what the issue is, is "how will a particular detectorist best interpret his/her machine's hints of a partially masked target?" Clearly, a totally non-masked target is one with no iron nearby, and thus presumably, no nulling would be occurring (and obviously, if within the machine's depth range, this is an "easy" target). Likewise, a totally masked target will give no response, by definition -- the machine simply can't "see" it. So, it seems to me there are three basic types of targets (assuming each is within the depth range of the machine) -- a totally NON-masked target, a TOTALLY masked target, and the in-betweens -- PARTIALLY masked targets. The NON-masked targets are the easy, textbook ones. The TOTALLY masked targets are simply un-detectable. So, it's those "in between" targets were are talking about. And thus, the question to me, is, which way of setting up the machine will allow me as a detectorist to be most likely to properly interpret whatever "hints" my machine is giving me that a partially masked target exists (since we know that the response, whether using digital, smartfind, or relying on tone, will likely not be near as "good" of a response as the machine would give to the same target if it were not in the presence of iron.)

Steve