[TenTec] Argo V and digital modes

[Duane Calvin]

Interesting - your response sounded as simple-minded as mine.  But then, I
agree, I'm simple-minded.

	73, Duane

Duane Calvin, AC5AA
Austin, Texas
www.ac5aa.com  




-----Original Message-----
From: TenTec [mailto:tentec-bounces at contesting.com] On Behalf Of Jim Brown
Sent: Monday, September 22, 2014 11:26 AM
To: tentec at contesting.com
Subject: Re: [TenTec] Argo V and digital modes

On Mon,9/22/2014 8:18 AM, Duane Calvin wrote:
> Well, strictly speaking, RTTY generated via FSK is a carrier mode,
however,
> RTTY generated via AFSK is an analog mode and still requires care to
> preserve linearity.

That's a simple-minded (and incorrect) view of AFSK and FSK. Regardless 
of how RTTY is transmitted, there is modulation, and modulation produces 
sidebands, both from the modulation waveform and from distortion 
produced by that waveform due to distortion in the RF chain. The only 
difference with AFSK is that it's possible to add distortion from the 
audio chain, and that one must pay attention to setting audio levels.

Conventional wisdom is that FSK is cleaner. Until Elecraft worked on it 
(in firmware), FSK had wider keying sidebands than AFSK in the K3. Don't 
assume that your rig is better. :)

73, Jim K9YC


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