[RTTY] Crystal filter width preferences for RTTY contesting

[Glenn Wyant]

300

300

VA3DX

----- Original Message ----- 
From: "Jeff Blaine AC0C" <keepwalking188 at yahoo.com>
To: <rtty at contesting.com>
Sent: Tuesday, August 25, 2009 1:23 PM
Subject: [RTTY] Crystal filter width preferences for RTTY contesting


> 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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