Pete KE9OA wrote:
The only mechanical filters that I have seen problems with are the Japanese
units that you find in the JRC receivers. There is some sort of foam that
deteriorates over the years. I haven't seen a problem with Collins filters.
I have an old Collins filter made for the R390 series receivers. It is
a cylindrical filter with two pins at each end for connections. I can
hear something rattling around inside this filter as I tilt it from side
to side. Has something deteriorated inside this filter or is this
normal? A later rectangular Collins filter does NOT make this noise.