Well, all components age, including crystals. I haven't noticed any
problems with the filters in my 44 year old Heath HW-100. I have
noticed increased insertion loss in the 500 Hz Ten Tec filter in my
Paragon. I haven't had time to open it up and swap filters around to
see if the problem is in the filter or the circuit. If it's the filter,
I'll try replacing caps on the filter board. If that doesn't work I
guess I'll have to replace the filter. The selectivity is fine; it just
knocks the signal down, compared to the 1.8 ans 250 Hz filters in the rig.
73,
Bob WB2VUF
On 10/27/2014 9:56 AM, Kimberly Elmore wrote:
In discussion of an Omni D, Rick and maybe someone else mentioned that old
crystal filters may no longer meet spec and can result in significantly reduced
sensitivity. I know that crystals age and that if they don't all age the same
way the filter may drift out of spec, but this is the first I've heard that it
could affect performance to such and extent. Is this a characteristic of all
crystal filters, or only those used in the Omni D series by TT? I'm curious
because I have INRAD filters in an older radio. They seem to work as they did
when I first installed them 20+ years ago and the radio seems as sensitive as
it ever was.
Kim N5OP
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