[Elecraft] 8 pole vs 5 pole..I knew this would happen

[Fred (FL)]

I think, still, someone needs to define what a ROOFING
FILTER is.   Say for sake of argument - I have a
passive or active or crystal filter - and it is to
be used as a ROOFING FILTER.   Why is it called this?

Why is the filter itself, called a ROOFING FILTER?
And where does the adjective, ROOFING, come into
play?

...... I'm sure I'm dumb on this one - but would
like to learn.  Not until the K3 came on the
Elecraft scene - did anyone mention or get
concerned about the need for ROOFING FILTERS.
Now they're all the rage?

Fred, N3CSY

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