[RTTY] Crystal filter width preferences for RTTY contesting

Jeff Blaine AC0C keepwalking188 at yahoo.com
Tue Aug 25 10:23:26 PDT 2009


Gentlemen,

I and a few other guys are working on a project to get a very high quality set of crystal filters built for the Yaesu FT2000.  The rig is an otherwise very fine unit but the front end is a mess.  This project is an attempt to address these short comings.  

And one of the questions that have come up is what the IDEAL width would be for the RTTY contester.  So I would like to ask your kind option here.  Anyone can reply this - while this is about a specific rig, I would like serious answers from serious operators so we can help to ensure the filter guys pick the proper width.

So the question (in 2 parts) is like this. 

ASSUMPTIONS:  Assume we are not going to rely on the DSP - and that the width of the DSP is wider than the crystal so it's essentially not being used for bandwidth limiting.  And assume that the final solution may have 2 filter sockets.  Shape factor of the filters is around 1.5:1 and the ringing, while present and measurable, is at such low levels as to be inaudible.

Q1. If you only were to get 1 filter, what width would it be?

Q2. If you were to want to fill both filter slots, what widths would these 2 filters be?

Thanks for your comments!

73/jeff/ac0c


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