Simple maths for this used to be shift plus twice the baud rate; 170 + (45 x
2) = 260Hz
I have used 250, 300 and 400Hz for contesting at various times. 250 is fine
almost all the time; never found the need for wider than 300. That would be
my choice for 2 options.
73,
John GW4SKA
----- Original Message -----
From: "Jeff Blaine AC0C" <keepwalking188@yahoo.com>
To: <rtty@contesting.com>
Sent: Tuesday, August 25, 2009 6:23 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
> _______________________________________________
> RTTY mailing list
> RTTY@contesting.com
> http://lists.contesting.com/mailman/listinfo/rtty
_______________________________________________
RTTY mailing list
RTTY@contesting.com
http://lists.contesting.com/mailman/listinfo/rtty
|