The three detection technologies, explained without marketing fog — so you can match the machine to your ground.
The three detection technologies, explained without marketing fog — so you can match the machine to your ground.
The classic: a single frequency (or a couple) transmitted continuously. Excellent discrimination — it can tell iron from silver — light, affordable, and the best choice for parks, fields, and beginners. Weakness: mineralized ground and wet salt sand confuse it.
Fires powerful pulses and listens for the decay. Ignores salt and heavy mineralization, goes very deep. Weakness: poor discrimination (you'll dig trash), heavier, pricier. The choice for goldfields and serious beach depth — e.g., the Garrett Axiom.
Transmits several frequencies at once (Minelab Multi-IQ/Multi-IQ+, XP FMF, Garrett Multi-Flex, Nokta SMF) and combines the returns. Near-VLF discrimination with near-PI ground handling. Weakness: cost, complexity, battery drain. The best all-round answer for most hunters in 2026.
Before VLF there was BFO: two oscillators, one in the search head, and metal near the coil detunes it — the audible "beat" between the two frequencies is the signal. Charles Garrett pioneered commercial BFO machines in the 1960s and it launched the hobby industry. It needs constant coil motion and discriminates poorly, so it's obsolete for serious detecting today, but every modern machine descends from it.
More versatile, not always better. Multi-frequency costs more, drains batteries faster, and adds settings complexity. A high single frequency still wins for tiny gold, and a simple VLF wins for beginners who'd drown in menus.
The machine transmits and processes multiple frequencies at the same time (not switching between them). Each frequency responds differently to targets vs ground, and the processor combines them — that's how salt signal gets subtracted while target signal stays.
Modern multi-frequency flagships come closest, but physics still applies: no single machine is simultaneously the lightest, deepest, cheapest, and best at tiny gold. Match technology to your primary hunting ground.
Beat Frequency Oscillator — the first electronic detector technology, commercialized in the 1960s. Two oscillators beat against each other and metal shifts the tone. Simple and cheap, but it needs constant motion and barely discriminates, so VLF replaced it for hobby use.
Technology marketing loves superlatives — 'most advanced,' 'deepest.' Ignore adjectives; compare documented behaviors: frequency set, ground-balance system, waterproof rating, weight. Those four predict real performance better than any slogan.