Iron Filter, How Does It Work?

[gilgsn]

Hello.

First real post here after my introduction.. I could not find and answer from a search.. BTW I have not bought a detector yet, waiting for the end of the month..

I understand how the iron filter works on the lower end, avoiding high-tone chirps on iron. It's on the upper end that I have doubts... So, based on the lower-end filter behaviour, one could deduce that a max iron setting filter would be best, no false alerts.. It seems however that above a certain level, nothing gets through... Am i right? There is probably something I am missing here, as to how an IF works. Could anyone explain this?

BTW if anyone here has a YT channel this would be a great video subject: How it works and how to set it... Most videos mentioning the iron filter seem to assume that everyone knows how it works...

Thank you very much!

Gil.