[Elecraft] K3 DATA A vs AFSK A

[Don Wilhelm]

Which data sub-mode is used is really a user's choice and is dependent 
on what data mode software is intended to be used.  Some waterfall 
display oriented data mode software will do fine sending and decoding 
RTTY as well as other data modes.  MMTTY (which is the main choice for 
RTTY operation) does not do a waterfall and you tune to the signal 
desired with the VFO.  A similar situation is true for PSK D and FSK D - 
you tune to the desired station with the VFO rather than clicking on a 
waterfall display.

For those who are not clear about the data sub-mode designations try this:
DATA A = Data mode (Audio) = waterfall display oriented (point and click)
AFSK A = AFSK mode (Audio) = Tune in a single station with the VFO
PSK D = PSK mode (Digital) = send CW with paddles (or ASCII in KY 
command), receive on K2 display or K3 Utility terminal
FSK D = FSK mode (Digital) = send CW with paddles (or ASCII in KY 
command or 'wiggling the FSK IN pin on the ACC jack), receive on K2 
display or K3 Utility terminal

Hopefully that helps with understanding of what the "A" and "D" suffixes 
mean.

In summary, if you are using an application that has a waterfall 
display, use DATA A and point and click on the waterfall to select the 
station.
How you use the data sub-modes depends on which software application you 
are using as well as the physical connections to the K3.

73,
Don W3FPR

On 3/17/2015 6:48 PM, Fred Jensen wrote:
> 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.
>
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