[TenTec] On Crystal Filters

[Bwana Bob]

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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