Metal Detecting

Has anyone ever noticed that the 11” coil makes a little click as you change frequencies or switch to programs using a different frequency? The other coils probably do also. I just noticed this for the first time as I was re-programming the remote but was surprised that the coil itself could make any sound at all, maybe it's some form of electromechanical switching?
You're all going to try this now.

Yep mine does too. On v4, don’t know if that makes a difference.

Yep my 11" has been clicking everytime that i change frequencys from day 1 , i was worried at first but same as you i put it down to mechanical.. Would be interesting to know what is clicking though

EDIT: i use the 3.2 version.

There's got to be a electronic switching relay in there, at a guess something to do with switching voltage for each frequency. Must be a reliable little relay as never heard of anybody getting one repaired or one failing.

Roberts wrote: Tue Apr 17, 2018 8:38 pm Would be interesting to know what is clicking though

That was my curiosity for posting. Someone electronically minded will know.

Yep hf coil does as well

There are two magnetically-latching relays in the coil, which are used to change the tuned frequency of the coil. Being mechanical, they click when switching over. I'm not 100% on the details, but the relay contacts switch in different capacitors that change the frequency the coil is tuned to. The coil windings ( the loop of copper wire ) is the same for all four frequencies. The magnetic latching means they only consume power when actually switching over. After that, magnets hold the switch in position.
They are Axicom IM41 parts:
http://www.te.com/usa-en/product-5-1462037-4.html
And here's the circuit board inside the coil:

These relays must be absolutely tiny.

They are fairly small, but there's enough room in the Deus coil for them.
For decades, the 'standard' in miniature relays has been the TO-5 packaged relays originally by Teledyne. Very expensive, usually used in Aerospace applications, and for very high frequency radio-signal switching. I've had the 'lid' off one in the past, they are works of art inside. My example was a magnetic-latching one, with two seperate coils for 'set' and 'reset'.
This is a typical version:
https://www.enrgtech.co.uk/buy/product/ET13974967/722-5