[GreenKeys] RTTY Selectivity choices in tube receivers

[Lee Mushel]

Accurate observations and a powerful argument for the adjustable filter
width of software defined radios!

Lee   K9WRU
----- Original Message ----- 
From: "Jeffrey D Angus" <jangus at socal.rr.com>
To: "Greenkeys" <greenkeys at mailman.qth.net>
Sent: Saturday, January 24, 2009 12:24 AM
Subject: Re: [GreenKeys] RTTY Selectivity choices in tube receivers


> John Hensley wrote:
> > I'm interested in what others think about selectivity filters for RTTY
in
> > receivers where there is a choice such as the Drake or Collins
receivers.
> Basic rule of thumb, 5 times the baud rate + shift = required bandwidth.
> 45 baud @ 170 Hz shift would be approximately 400 Hz minimum bandwidth.
> 45 baud @ 850 Hz shift would be approximately 1200 Hz minimum bandwidth.
>
> "Back then" I seem to remember the following filters being available:
> 400 Hz for CW
> 1.2 or 1.4 KHz for RTTY
> 2 to 3 KHz for SSB
> and 5 to 6 KHz for AM.
>
> Jeff-1.0
> wa6fwi
>
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