[Elecraft] K3 DATA A vs AFSK A

[Fred Jensen]

Hmmm ... this may be the first time Fred Cady's book has failed me.  I 
understand now "what" each mode does.  What's still not clear is "why 
would I choose one over the other?"  Operator/User manuals tend not to 
answer that question, they are understandably focused on exactly how to 
operate the equipment.

I'm very sure that, when I first set up RTTY, I went to AFSK A because I 
knew what audio frequency shift keying was and I didn't know what DATA A 
was.  It all worked, so I never changed it or tried out the other 
choice.  I guess if AFSK A is LSB and works with MMTTY in its default 
configuration, then DATA A is USB and I'd have to reverse the tones in 
MMTTY.

I'll leave it as I've been using it, it works so it obviously doesn't 
need fixing.  I was just curious.  I have my "pitch" set at 915 Hz, I 
can't hear 2,125 Hz.  Thanks Joe and Mike.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 50th Running of the Cal QSO Party 3-4 Oct 2015
- www.cqp.org

On 3/17/2015 10:07 AM, Joe Subich, W4TV wrote:
>
> On 2015-03-17 12:41 PM, Fred Jensen wrote:
>  > Can you 'splain the difference between AFSK and DATA A?
>
> AFSK A and DATA A are both audio modes.  AFSK A uses LSB
> and FC is set to MARK - 85 Hz (the center of the two RTTY
> Tones).  DATA A is USB and FC is set to 1500 Hz (the center
> of the transmit audio passband [200 - 2800 Hz]).
>
> AFSK A also allows use of the AFSK transmit filter (a tight
> filter around the Mark/Space tones to eliminate hum/pops/etc.)
> and the use of the Dual Tone filter on receive.