Atrex currently has a Water Reject function, which is the simplest use of more than one frequency for operation in a metal detector. The transmitting signal is not specially formed, we simply take advantage of the natural presence of harmonic frequencies in a rectangular signal. Research and experimentation on the real Multi Frequency work has been going on in RUTUS for a long time. The Atrex has, for good reason, a processor three times more powerful than the one we used in previous models, and similar but different solutions for the detector electronics itself. The main problem in talking about Multi Frequency is the advertising material you have seen for many years. The amount of irrelevant and sometimes misleading information is overwhelming. They are intended to convince you of this technology, not explain how it works. The first most important point is the number of frequencies. You can often see in various advertising materials how many frequencies are emitted by Multi Frequency detectors. The important thing is not how many frequencies the detector transmits but how many it RECEIVES - how many frequencies it simultaneously analyses in order to detect an object. Transmitting a frequency not received by the detector is just a waste of unnecessary energy. If you are standing in a dark courtyard and want to keep an eye on the gate and the garden gate at the same time, how many torches will you use? Two, only two are enough for this task. Any additional ones that shine into the sky are just an unnecessary waste of batteries. The transmitting signal has to be optimised to transmit ONLY those frequencies that the detector receives and this issue, in itself, is complicated. The second point is the drawings showing that for each object there is a single best frequency designed to detect it. Yes, it is true, but concerning SINGLE FREQUENCY detectors. Is this how Multi Frequency detectors work? Of course not. To describe the topic roughly: single frequency detectors use a resistive signal ("Y") to detect objects, whereas Multi Frequency detectors use magnetic ("X") signals from multiple frequencies. The X signals behave differently from the picture we are all familiar with. How many frequencies will the Atrex operate in Multi Frequency? As many as needed to achieve all the desired features. Another lingering myth to deal with is that Multi Frequency is "slow". The first Multi Frequency detectors were developed and designed on the basis of 8-bit microcontrollers, with a clock of 3.9 MHz. The efficiency of such a "monument of technology" is only 1.4% (!) of the Atrex processor.

Multi Frequency designed today does not mean "slowness" and has a number of advantages:

- there is no need to select frequencies for the searched objects, the detector detects small and large objects well,

- no detector response (or the response reduced many times) to any conductive, non-metallic substances in the ground, e.g. sea water, coke, shales, etc.,

- no influence (or very little influence) of the magnetic and conductivity of the soil on the ID of the objects,

- more effective detection in highly mineralised ground (both in terms of the presence of magnetite and its conductivity).


Multi Frequency software for Atrex is currently in the final stages of testing in various parts of Europe, the feedback has been very positive.

It will be available to download for free on our website in the near future.


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