[RTTY] The Problem with AFSK ...

Joe Subich, W4TV lists at subich.com
Sat Jan 19 13:21:06 EST 2013


 > I think you are confusing technology with operator skill.

No, I'm viewing the entire "system" ... you're very correct that it's
relatively easy to generate a cleaner signal *from the sound card* in
AFSK but there are so many more opportunities to screw it up in the
interfacing and so many do screw it up.  It only takes a little bit
of listening to any of the digital bands/modes to hear all kinds of
*rotten signals* (with respects to HPM).

While there is nothing that the sound card developer can do, FSK is
done in the transceiver so although the implementations may not be
the best, there is very little (perhaps some severe common mode RF
feedback) that can be done that will make it worse - unlike the
hundreds of improperly adjusted or connected sound cards we hear on
a regular basis.

As transceiver makers move sound cards into the rig, it will be easier
(perhaps) to generate clean AFSK and other audio based digital modes.
However, there is no reason not to expect (and lobby) those same
manufacturers to make use of the DSP modulation capabilities in their
new rigs to generate equally clean FSK.

73,

    ... Joe, W4TV


On 1/19/2013 12:50 PM, Peter Laws wrote:
> On Sat, Jan 19, 2013 at 11:00 AM, Joe Subich, W4TV <lists at subich.com> wrote:
>
>> This behavior is all to typical of AFSK signals where the audio is
>
>
> I think you are confusing technology with operator skill.
>
> I have no doubt that W7AY can put out a cleaner RTTY  signal using
> AFSK than I can with my IC746Pro running FSK, but FSK is a LOT harder
> to screw up.
>
> Any mode that requires that an audio signal be fed to a transceiver is
> just begging to be screwed up ... and often is, as you've just
> reported!
>
> But that's not the fault of AFSK - that's the fault of the operator.
>
>


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