Explainer
VLF vs PI metal detectors
A VLF detector runs a steady frequency, such as 10 kHz on the ACE 400, and many add a target ID. Pulse induction sends pulses instead. None of the four PI detectors we read lists a target ID scale, and the three full-size ones weigh 4.2 to 5.1 lb.
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VLF, a steady wave
VLF stands for very low frequency. The coil sends a steady wave, and the detector reads both the strength of the reply and how far it lags behind. That lag is what lets it tell iron from coins. On models like the Goldmaster 24k, it becomes a number: 0 to 99.
Makers tune the frequency to the target. Garrett's ACE 400, a single-frequency VLF, runs 10 kHz. Gold models go much higher: 48 kHz on the Goldmaster 24k, 71 kHz on the Gold Bug 2.
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Pulse induction, pulses instead of a wave
A pulse induction detector sends short bursts of current and listens to how the reply dies away between them. Seawater and mineral ground fade fast, while metal holds its reply longer. The PI models here are set up for both. The SDC 2300 lists a Salt mode, and the GPX 6000 offers Ground Type: Normal, Difficult or Severe.
Minelab's GPX 6000 and SDC 2300 and Garrett's Axiom publish no kHz value. Nokta's PulseDive page, read Oct. 16, 2026, does list one for that handheld diving detector: 3 kHz.
| Model | Technology | Frequencies | Waterproofing | Weight |
|---|---|---|---|---|
| Garrett ACE 400 | Single frequency | 10 kHz | Not published | 2.9 lb1.32 kg |
| Garrett Goldmaster 24k | Single frequency | 48 kHz | CoilWaterproof part | 3.4 lb |
| Fisher Gold Bug 2 | Single frequency | 71 kHz | CoilWaterproof part | 2.9 lb |
| Minelab GPX 6000 | Pulse inductionGeoSense-PI | Not published | 3.3 ftCoil only, 1 m | 4.6 lb2.1 kg |
| Minelab SDC 2300 | Pulse inductionMPF | Not published | 10 ftDetector, 3 m | 5.1 lb2.3 kg |
| Garrett Axiom | Pulse inductionUltra-Pulse | Not published | Not published | 4.2 lb1.9 kg |
Facts from the pages of Garrett, First Texas Products and Minelab, read Oct. 16, 2026.
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What you trade with PI
Weight is the first cost. The VLF models in the table weigh 2.9 to 3.4 lb. The full-size PI models run from 4.2 lb on the Axiom with its 11-inch coil to 5.1 lb on the SDC 2300.
Sorting targets is the second. With no ID scale on any PI model here, you dig more of what you hear. What you get instead are modes for hard ground, such as the Axiom's Fine, Normal, Large and Salt.
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Questions
Neither is better overall. The PI models here carry modes for ocean beaches and goldfields. VLF suits parks and fields, where a target ID saves digging trash.
Not by target ID on the models we read: the GPX 6000, SDC 2300, Axiom and PulseDive list none. The SDC 2300, Axiom and GPX 6000 offer ground modes instead, listed above.
They run several frequencies at once and keep a target ID. The Equinox 900 pairs Multi-IQ with 4, 5, 10, 15, 20 and 40 kHz settings. Our how it works page explains the three technologies.
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