[Elecraft] Re: filter selection

[Bill Tippett]

Hi Wayne,

N6KR:
 >The key point here is that these are all filters
*are* offered by other manufacturers -- but at
their 2nd or 3rd IFs.

 >We offer them at our first I.F.

         Of course most of those filters are
going into rigs without an infinitely variableDSP filter following 
them.  My point is that
you introduce unnecessary complexity with the
vast number of roofing filters.  400 vs 500,
250 vs 200, etc.

         As one example here are Elecraft's
own specs for the 400 8-pole versus 250 8-pole:

Filter          6 dB BW 60 dB BW

KFL3-400K               435 Hz  935 Hz
KFL3-250K       370 Hz  785 Hz

In my opinion these filters are redundant
and unnecessarily complicate the ordering
process.  65 Hz difference in 6 dB BW is
hardly worth bothering with, especially
since both are 8-pole and their IMD/BDR
performance is likely to be identical.

         It's your decision of course but I'm
a believer in "keep it simple".  I would
offer only the best filter for a given BW,
predetermined by Elecraft and based upon
actual IMD/BDR measurements inside the K3.

                                 73,  Bill  W4ZV