Five Frequency Times Eight

[Geotech]

As frequency increases the response strength of salt increases so running at 17kHz will be very noisy. To run a single frequency machine in salt you want to go the other way. The Fisher 1280x (2.4kHz) is actually usable in salt water because of its low frequency. However, it sucks on gold jewelry but would be a good choice for finding Atocha bars.

This is why MF detectors are so valuable in salt. You can notch out the salt and still get a lot of the jewelry. Nothing's perfect though, and often when you get underwater with swells overhead the salt response phase can move around a little and cause noise. If you have a speed/SAT setting then speeding it up might help, although you gotta be careful not to make it too fast. You can't swing a coil very fast in the water and for this you usually want a slower SAT speed.