[Elecraft] Re: bandwidth of OP1

[Wayne Burdick]

Hi Roland,

Our models and measurements of the KSB2 filter came in at an average of
2.2 kHz, with some small variation from one crystal lot to the next.
This result has been duplicated by others, most recently John
Grebenkemper, KI6WX, who wrote an application note regarding improving
the ultimate attenuation of the filter in receive mode. John has more
recently modeled filters with wider bandwidths and in some cases less
ripple, using the same topology represented by the KSB2 PC board. Of
course termination impedance of the filter is critical for obtaining the
correct bandwidth. 

Eric and I will re-model the filter using the crystal parameters you
measured. Thanks for this information. You might also want to compare
notes with John, at KI6WX@pacbell.net. I copied him on this e-mail.

73,
Wayne
N6KR