[Elecraft] K3: FSK-D vs AFSK

[iain macdonnell - N6ML]

The choice between AFSK and FSK is really about how you transmit, not
how you receive. With FSK, you feed an on/off signal to the K3 to
shift frequency, where with AFSK you send audio tones. You can
increase the receive bandwidth in FSK D mode just as you can in AFSK A
mode.

If you have KRX3, you can use a stereo sound card and two instances of
MMTTY - one configured to look at the left audio channel (main RX) and
the other the right channel (Sub-RX), and tune around with VFO B, in
split mode, looking for "the other guy", and then taking his
frequency.

73,

    ~iain / N6ML



On Thu, Oct 13, 2011 at 1:34 AM, Jim Miller <jim at jtmiller.com> wrote:
> I played a bit with FSK-D and AFSK today. I was able to get FSK-D to decode
> and display on the PC via the K3 Utility Terminal tab.
>
> While listening to T32C working a split RTTY pack I realized that trying to
> figure out which was the most recent worked station was a bit more difficult
> than doing it for CW, especially since the UP distance was 8-9Khz.
>
> I thought AFSK and display of the sigs on the PC screen might be of benefit
> but after putting it all together I realized that the bandwidth of the audio
> out would limit the spectrum to less than 4Khz.
>
> So what's the benefit of AFSK over FSK-D?
>
> Any suggestions for finding the last station worked in a pack?
>
> TIA
>
> Jim ab3cv
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