Fisher CZ series 8" Spyder - Quicksilver

[WM6]

Does anyone know if this coil has any other passive or active parts inside than TX and RX coils (inductors)?

As multi-frequency coil, presume that there are inside TX and RX coil only, but I am not sure?

Intend to buy one (have opportunity here locally) if nothing else inside than coils.

[Dave J.]

Transmit, receive, and feedback windings. I don't remember the exact resistance and inductance values which of course have to be measured at the searchcoil connector. No passive components. Alignment is critical because it's multifrequency and concentrics aren't very good at that. Unlike many designs, the inductive reactance and series resistance of the receiver coil is critical because the receive circuit is parallel resonant.

If you're thinking of a do-it-yourself searchcoil project, I'd recommend that you start with something other than a CZ. They're difficult to do. If you decide to try anyhow and if you have experience building DD's, I'd recommend doing a DD, not a concentric.

[WM6]

Thank you Dave, I really appreciate your help.

My intention was not to reproduce CZ coil, but to test, how it perform in some (mono-frequency) DIY VLF/IB projects.