[GreenKeys] RTTY Selectivity choices in tube receivers

[WA5CAB at cs.com]

John,

Assuming you mean on HF with FSK and 100 WPM or less and standard 850 Hz 
shift. of the commonly available filters you need a 2.8 or 3.0 KHz filter.  For 
170 Hz shift, 500 Hz filter.  

FSK is FM.  A simple rule of thumb for FM is that the receiver bandwidth 
needs to be greater than the peak to peak deviation plus at least three times the 
highest modulation rate.  FSK is a special case but the rule still isn't far 
off.

In a message dated 1/23/2009 11:10:48 PM Central Standard Time, 
w5jv at hotmail.com writes: 
> 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.
>  
> Enjoying the list,
>  
> John W5JV

Robert Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480
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