Monday, May 30, 2011

5/30/11 Report - Memorial Day Issue - Signal Nulling & Glass Detective Work

Figure 1.

People don't spend enough time experimenting with their detector, and they don't use pin-point mode enough. I've found that I can tell a lot about a target by the signal when I am in pin-point mode. Even though I generally dig everything, it can still be helpful to know what you are digging. You can recover items more quickly and avoid damaging them if you know what is in the ground.

Elongated iron objects like nails or spikes can be identified by the signal with a high degree of accuracy when you are using pin-point mode.

Figure 1 shows a nail or spike laying across your path when you are sweeping the coil from left to right and back. When you sweep over an object like this, perpendicular to the object, you will get a strong steady signal over the object, which in the figure is represented by the red circle over the object.

Figure 2.

However, if you then sweep your coil over the object again at at 90 degree angle to the first sweep, you'll hear a broken signal. If you sweep along the length of the elongated object you'll get a signal at each end of the object and a nulling or interruption in the signal right over the object.

So if you hear one signal when sweeping in one direction and then a broken signal sounding something like two separate signals when sweeping at a ninety degree angle, the probability is that you have detected some sort of elongated object. If you don't know about this, you might have trouble digging the object. The tendency is to dig too far to one end or the other of the object where one of the signals from the broken signal seems to be coming from.

Test this for yourself with your own detector. Just throw a nail or spike on a clean spot of ground and then run your detector over it in both directions. Listen to the signal and remember what it sounds like.

In fact, anytime you find a a new type of object, run your coil over it multiple times from different directions and carefully listen to the signal and try to remember what it sounds like. Repeat the process with multiple detectors if you have more than one. And try different detector settings. But don't do that all at one time. Use your primary detector and normal settings first until you have that signal well memorized before trying too many variations.

I mentioned the other day that I found a few different types of objects. Below is one. It is a nice piece of sea glass that you might be surprised to learn would easily sell for a small price. The color is one thing that makes it a bit unusual. Red and yellow also desirable and marketable colors for sea glass.

Foam Blue Sea Glass.

As I've been saying, many finds are valuable for the information that they provide even if they are not economically valuable. A piece like this does have some small economic value but can also help you date a site.

I often keep samples of glass and ceramics that I find, and I thought I had a piece of this type of glass that might tell something about how old it might be. I thought I might have a bottle or piece of a bottle made of the same type of glass, so I checked and found a matching piece. As I thought, the matching piece is part of a bottle. From the base shown and from what I remember of other matching bottles that I've seen, I would say this is probably from a Hutchinson Bottle or similar soda bottle.

Part of Bottle Matching Recent Sea Glass Find.

As a result of my detective work, I would say that the piece of sea glass is probably from around the early 1900s. At least that will be my working hypothesis until something provides more information and changes my mind. That rules out Spanish shipwreck and alerts me to the possibility of other items of similar age at that location.

One point I am making here is that some items can provide useful information even if they are not worth anything, and second, the broader your knowledge base, the better, and third, keeping a collection of samples from old finds can also be helpful.

One additional note, the broken bottle is closer to the color of the sea glass than it would appear from the photos. The lighting is different and the frosting from tumbling changed the appearance of the sea glass.

On the same topic, if you want to learn more about any type of artifact browse through as many samples as you can. it doesn't matter if you want to learn more about bottles, fossils, Indian artifacts or shipwreck artifacts, you can browse through many examples on eBay or other auction sites. Of course you can find many books on every subject anymore, but I find the internet very quick and easy.

I posted the previous day's post before proof reading it, and it had a lot of typos and mistakes in it. Sorry about that. I just tried to do it too quickly. I do that every once in a while.

Don B. sent me the following link to a great article on the Queen Anne's Revenge. They raised the anchor and are talking about a variety of things including some interesting conglomerates.

I think you'll like the article.

I just realized that I should have showed some Treasure Coast WW II artifacts today.

Treasure Coast Beach Forecast and Conditions.

The wind is now pretty much from the east. The seas are a little rougher and the swells building to about 4.5 feet for Tuesday and Wednesday. Almost that big today.

As I've been saying that should help freshen up the beach fronts a bit.

The beach is building this morning although I saw a couple of spots where a little sand was removed, but it was an insignificant amount.

There is also a lot of sea weed on the beaches this morning. That is never a good sign. A lot of bottles and plastic is washing up, and on the beaches that I saw, the shell piles were gone.

Be safe.

Happy hunting,