by Phil. Stearnes --- Gold Mining Centre, Holden Hill, S.A.

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Last month we mentioned about some club members rubbishing certain detectors and not helping these members to learn their particular detector. An incident has happened since then that I think needs mentioning. A person who was looking at joining a club went along to a meeting to see what it was like. Several things occurred there, but the one I thing that I believe needs airing is as follows. During the meeting, a fellow member ( lets call him Ted) started talking about the detector he was using and was telling this possible new recruit ( lets say Ian ) that this was the only detector to buy. In return, Ted was told by Ian that he had

already purchased a detector and what brand and model it was. Ted then replied that he shouldn't have purchased such rubbish as they do not work in Australian conditions. I must point out at this time that we are talking about a coin detector.

Ted then said that he had detected a gold American coin at 23 inches deep at the beach with this particular unit. Eyebrows were raised by Ian, as if in dismay and then Ted said that he had measured it and then turned to another member and got him to confirm it. Ian then turned around and said that he had been finding lots of items with it, including rings, during the week of ownership of his new detector. Luckily Ian wasn't a raw beginner as he had previously detected years ago and knew about this hobby. Even with this knowledge he still wondered whether he had purchased the correct detector.

I put damage control into action and explained a few things about this claim. Firstly this find was reported to the club as being found at 18 inches. In this magazine it was reported at 14 inches. To start with, this falls way short of the 23 inches that he was told. When digging in the sand, the target can be missed and can fall further into the hole giving an indication that it was found at a much greater depth. Under normal circumstances, the majority of coins are found at a maximum depth of between 8" and 12". This can slightly vary with different operators and coil sizes. We know what fish stories are about and how there is a gross exaggeration on sizes, well this is the same in detecting. So come on detectorist's, no more of these far fetched stories as all it can do is hurt the industry. People will expect to get these results with a particular detector and will be grossly disappointed and this will only hurt the reputation of that detector, which is not justified. We have a responsibility to the industry, so lets do the right thing. By the way, due to this episode plus other things, this club lost a total of eight new members that were intending to join.

The way I instruct people to learn this function is as follows and I believe it is an easy way to remember. I first set up the audio threshold so that you can just hear it. Next I instruct them to only listen to the threshold when the coil is being brought down towards the ground, indicating to never listen to what happens when the coil moves away from the ground. I then explain that it is like a radio, that is when the audio becomes to loud you turn it down and when it becomes quiet you turn it up. This is the same principal with metal detectors.

When bringing the coil down towards the ground and the audio threshold decreases, then turn the ground balance up, which is normally clockwise. If the audio threshold increases when the coil is being brought down towards the ground, try another spot just slightly away from that spot. The reason being that they may be trying to ground balance over a target. If it still increases, then turn the ground balance down. This is done until a very slight positive signal is obtained when the coil is being brought down towards the ground. This is a very slight increase in audio threshold. Most areas require a slight positive ground balance but we have found several areas in Victoria where a slightly negative ground balance is required.

With a manual ground balance detector, ground balance will have to be adjusted more often, if the ground mineralisation varies a lot. With an auto ground track detector, it optimises for ground effects (averages out ). With a manual ground balance, precise ground balance can be achieved but the operator must work at it. If remembering this way of ground balancing, that is if a radio is too loud you turn it down and if it's too quiet you turn it up. This is exactly the same with detectors. The most important thing to remember, is to listen to the audio only when the coil is being moved towards the ground and never when the coil is moving away from the ground.

Always use a coil cover when detecting. It's surprising how many people fail to do this. We often see units come in that have not used coil covers and the coils are in very poor condition. Usually we find the bottom of the coil extremely worn and even worse, the sealant joining the two halves of the coil together badly cracked or even the coils cracked. If moisture happens to enter the coil through these cracks. it could mean the end of the coil. If one intends to sell the detector at a later date, and the coils are damaged, don't expect a good price as it makes it hard to resell in this condition.

If storing a detector away for any length of time, please remove the batteries. It's still surprising how many detectors are coming in for repair due to batteries leaking. Battery leakage can cause severe damage to a detector and can become very expensive. Prevention is better than a cure and is also cheaper, so don't leave any batteries in a unit when storing as you are only asking for trouble.

Using the older style T.R. discriminator, you must keep the coil at a constant height otherwise noises will be heard when the coil is moved up or down in relation to the ground surface. I found the best way to use these older style detectors was to detect in the " All Metal " mode ( known also as G.E.B. ) and when a target is detected, I would then switch to T.R discrimination and check the target. A technique called " Scrubbing " is really worth learning as you will find that you locate many more targets. I did this in both V.L.F. and T.R. mode. Scrubbing is where you keep the coil on the surface all the time. Make sure that you are using a coil cover, otherwise you will wear a hole through the coil. My coil covers use to last me about four months, but the extra targets I found more than paid for it.

When working the wet sand, always work towards the water and going away from the water. There are two main reasons for this. The first being when you move the coil left to right, the moisture contents of the sand will be more constant side to side than working parallel to the water. By working this way, it will reduce noises that are caused by the changes in moisture content. With motion detectors, which most coin machines are today, false signals can be obtained at the end of each swing if working parallel to the water. Working towards and away from the water should stop this. Another thing also to remember is not to use too much sensitivity, as this could also make the unit unstable as well. Most detectors these days have more sensitivity than is normally required.

The other reason is that if you work parallel to the water, you could be missing all the good targets. By working towards and away from the water, you will notice that usually a pattern will form on the good targets as well as the light rubbish. By observing this, sometimes you can actually discover where all the good targets are, and you can work this area. This can sometimes become very rewarding.

GARRETT A3B DETECTOR. ## This detectors reputation suffered due to being fairly noisy on very hot ground. Many people said that the Garrett A2B, which was the previous model, was a much better unit. Early last year, I did a write up in this magazine on how to solve this problem. By substituting the 8 1/2" coil with a 10" x 5" elliptical coil that is used on the Garrett Scorpion, this problem is greatly reduced. The A3B then becomes a better unit than the A2B but still not as good as the Scorpion. Just over a week ago before writing this article, I supplied a Scorpion coil to a person staying at Dunolly. I received a post card from him thanking us for the quick service and that he was exceptionally pleased with the new coil. He said that it was a lot quieter in operation and the first time he used the A3B with this coil, he found a 2.2 gram piece of gold. It's good to see people being happy with their equipment and if we can help others by letting them know of any improvements, we will certainly try to.

Well that is it for another month. As we said before, if you have any problems or queries, please write to us at the " Gold Mining Centre ", Shop 2, 1048 Grand Junction Road, Holden Hill,  S.A.  5088. We will try to answer all questions if possible, through this article in the magazine. All the best until next time.