A pain in the ear

Jonathan Porter

I’ve noticed three major types of interference since the inception of PI machines; one is the earth’s magnetic field following the contours of the ground, the other is a reflection of this via atmospheric occurrences and finally man-made which is by far the worst. I can deal with the naturally occurring ones because you know they are going to dissipate given time but it is the man-made ones we seem to have no control over, in fact they seem to be getting worse as urban sprawl and aircraft travel increase.

A few years back Frieda and I bought a property in central Queensland where a large high energy power line (66 000 volts) runs right through the guts of some of the best gold diggings on the block. As you can imagine this plays havoc with our modern high sensitivity gold machines, to the point where I don’t make a habit of working in the general vicinity because of a low tolerance to any sort of interference (I hate interference with a passion). Last year I headed west on my own leaving Frieda and the boys at home to have a break from the nomadic life style for a season; actually to my embarrassment Frieda would often find more for the day than I would in the west, where I was in supposedly prime nugget country.

When I returned I asked Frieda to take me around and show me where she had been finding her gold. To my amazement it was all within cooee of the bloody power lines; “how the hell do you put up with all that interference, Cancel mode”? “Nope, I just wait for the wind to change” says Frieda. “That’s how I ended up so ugly” I replied, but seriously how do you work so close? Looking me straight in the eye, (which means she means business and I had better start paying attention) she repeats, “I wait for the wind to change and then I can work right up to them”. Well I had to try this out for myself so on the next decent breeze that came by I grabbed Frieda (with her 11” DD) and headed up to interference hell, using a 14” DD and normal settings I was surprised to find that it was manageable, yet on the down-wind side it was horrendous!

It seems that the energy created by power lines is affected by wind, so much so that if the breeze is strong enough you can detect very close without undue problems (on the up-wind side), but heaven help you if you go down-wind because the interference can carry for miles. Frieda the clever little observant thing had noticed this and taken full advantage of this most unusual phenomenon massing an impressive five ounces for the season, all of which was found detecting roughly six hours a week with the kids in tow.

If you have high voltage power lines running through your favorite prospecting area and would like to try your luck in some of the untouched ground, then (dosing up on some beans!), wait for a very windy day to reap your reward; only remember to keep up-wind!!