Hi Jeff. Take a look at the Icom IC756Pro3 RTTY filter scheme. It is the
best that I have used.Here is a link to some info.
http://www.rttycontesting.com/icom756proiii/icom_ic756proiii_index.htm
Also AB4OJ has a bunch of technical info as well.
Randy N1KWF
On Tue, Aug 25, 2009 at 1:23 PM, Jeff Blaine AC0C
<keepwalking188@yahoo.com>wrote:
> 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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>
--
Randy Lake N1KWF
73 Gunn Rd.
Keene,NH
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