GPX4000 - auto tuning

Hi ,, with auto tune on my 4000.. I,ve been told to sit the machine on the ground with the coil facing the nearest power lines,. Another was face the coil towards the east because thats where the main interference is ???? When working with other detectors hold the machine at waist height and point it at the other detectorists whilst tuning,,

What is the corect method please

Hi Nuggetman,
I was told at Minelab training day to place coil on the ground and autotune.
Don't know if this is ideal but seems to work.

Michael

There's two schools of thought on this: Some say you can just put the detector down on the ground and hit the Auto Tune Button. Others say you need to follow the mantra set down by older detectors and turn in a circle before deciding on which direction to place the detector BEFORE hitting the tune button. If you want to be thorough, consider the following procedure:

You need to turn the detector on, hold the unit out from you (with the coil facing away) and then turn slowly in a circle. Listen for the direction of the highest amount of interference and then place the detector on the ground with the coil pointed towards the source of the interference. Press the Tune button and wait 60 seconds for the tuning procedure to complete itself.

After the tone (3 beeps on the GPX-4500), you can then commence detecting. The detector should have identified the noisiest channels and has selected the quietest channel to operator on with the least amount of interference.

When detecting with multiple partners, turn each machine on and tune it one at a time.

I'm currently making a short video showing the setup procedure for the 4500. Here's a couple of images in advance.

I have never fancied that way of tuning, its ok i guess if there is strong horizontal signals present, or your working the embankments of a creek, but the majority of signals present would be vertical. Man made interference is more common in this polarisation.
Vertical to horizontal exhibits less signal strength compared to using two antennas of the same polarisation facing one another, therefore tuning in the vertical position should by way of design tune out far more of the signals from this polarisation then tuning it whilst its horizontal.
There are however many exemptions to this then i care to mention,,,star pickets are vertical whilst the wire attached is horizontal.
Power poles are? whilst the wire they hold is ? and the radiated field from the wires are?

Food for thought.

Both methods will probably achieve a similar result. I can't say if one technique works better than another. The advantage of turning around to isolate the strongest interfering signal is that there's usually a distinctly strong EMI coming from at least one direction. And it's loud enough and strong enough to be directional. By using this signal to assist in tuning the detector, the results are a little like the act of using a hot-rock to re-balance: You end up ignoring the majority of the unwanted signals. Anything that will obscure the sound of a legitimate target should probably be avoided, including EMI.

EMI is omnidirectional and radiates from the point of origin. The radiating field is always in motion but anchored to the source.