Choosing The Gold Machine That’s Right For You
There is no one “best” gold machine, just like there no one “best” car. There’s only the one that’s best for you (or maybe several of them if you’re really serious). Here are some things to take into account when choosing.
1. Any metal detector will detect gold nuggets if they’re big enough, but most gold is small stuff. If you’re planning to do gold prospecting, you should get a machine which is capable of doing at least a halfway decent job of it. There are good medium performance “coin-shooting” machines down to about the US$200 level. However, highly capable gold detection requires specialized design, and you won’t get medium performance gold detection for much under $500.
2. If you plan to do general metal detecting (coins, jewelry, relic hunting, etc.), you can get that capability without spending more. However the low operating frequencies required for general purpose metal detecting mean you will sacrifice a little bit of sensitivity to the smallest gold, compared to what could have been achieved at a higher frequency.
3. There is not necessarily a close relationship between price and performance. Features and branding have a lot to do with price.
4. For most people, buying from a local dealer is better than buying over the Internet because the dealer will usually be able to provide good advice on what to get for your purposes. Pricing at local dealers is usually about the same as from Internet dealers or only slightly higher. Some Internet dealers provide very good service although they can’t literally demo a machine for you.
5. Manual ground balancing capability is important for many users: however some people just can’t get the knack of it and require a machine that offers computer-assisted ground balancing, either “grab” or “tracking”. Tracking may sound like a good feature, but it’s like driving an automatic transmission car on a narrow winding mountain road— constantly changing and unpredictable. With “grab” there is no tracking and you can get a repeatable signal when checking out a target.
6. About operating frequency: there are gold machines the operating frequency of which ranges from about 6 kHz up to 71 kHz. The highest frequencies are best for the tiniest gold, which of course is most common. Finding small gold keeps you in the “gold is where you find it” groove so you’re more likely to swing the search-coil over larger gold. The lower frequencies tend to be easier to ground balance especially in moist ground conditions, and to give slightly better response to large nuggets. The frequency range of 13 kHz to 19 kHz is especially popular because it’s a good compromise for gold, and because this frequency range is also suitable for general-purpose metal detection (which the higher frequencies aren’t).
7. Multiple simultaneous frequency machines presently on the market are not suitable for gold prospecting, with the exception of the very expensive White’s V3 which is really intended for other uses.
8. The prevailing gold machine technology at US$1500 list price and up is pulse induction (“PI”) with ground balancing capability. The operating principle is different from VLF and the ground balancing issues are also different. The main advantage of a good PI is its ability to work in heavily mineralized ground without much loss in depth, especially on the larger nuggets. The disadvantages are cost, weight, poor response characteristics, tendency to miss the smallest nuggets, poor sensitivity to meteorites, high power consumption, and rudimentary feature list. Because what a PI will and won’t find is quite a bit different from what a VLF will find and won’t find, some users will cover an area with both a PI machine and a VLF machine in order to “clean it out” a lot better. Some PI users have convinced themselves (having spent so much money) that no VLF machine can match the performance of a PI. That’s certainly true in some conditions. But there are also prospectors who have both a good PI and a good VLF and prefer the VLF on most sites.
9. Most gold machines are available with at least two different sizes of search-coils. Advantages of small search-coils: higher sensitivity to the smallest nuggets, ability to get between rocks and bushes where larger search-coils won’t fit, lighter weight, reduced interference from ground minerals, easier to pinpoint the exact location of an object and less electrical interference. Advantages of larger search-coils: broader sweep (covers more area), slightly more depth (but not as much as you’d think). A popular compromise is an elliptical search-coil about 10 inches (25 cm) in length by about 6 inches (15 cm) wide, providing some of the advantages of both large and small search-coils. On a really productive site, some people will search it thoroughly first with a small search-coil to find the gold “hot spots” and to remove trash metal and hot rocks, then work the area again with a larger search-coil to better detect any larger deeper targets which may be present. If the detector has “speed control” (which won’t necessarily be called that — consult the user’s manual), use a slower electronic/software speed setting when the larger search-coil is installed. It’ll get more depth.
10. Some gold machines can be purchased with search-coils in either the concentric and double-D (DD) configuration. The big advantage of DD’s is that they penetrate ground minerals deeper than a concentric. Minor advantages of a DD compared to a concentric of similar overall size and shape are a broader sweep (wider coverage) with tighter target separation. However, DD’s have numerous disadvantages: greater vulnerability to electrical interference, confusing multiple signal responses on shallow objects, inferior shallow iron discrimination when used in discrimination mode, greater manufacturing cost and often less sensitivity to the tiniest nuggets. For gold prospecting the advantages of the DD usually outweigh the disadvantages. However the situation is not so clear-cut with small search-coils where concentrics are often more sensitive to the tiniest nuggets.