JT,
There is nothing wrong with AFSK - in fact, if the carrier balance on
the KSB2 board is adjusted correctly, AFSK is indistinguishable from FSK.
The only 'problem' with the K2 is that the BFO range is limited, with
the result that narrow filters cannot be set with a center frequency
equal to the 'true RTTY' tones. MTTY and other soundcard RTTY programs
offer a selection of tone frequencies - so if you align your narrow RTTY
filters to at 800 or 1000 Hz, MTTY can accommodate that center
frequency. When I set up RTTY filters on a K2, I set the FL1 filter the
same as the SSB filter and then set FL2 at 1.00 kHz, FL3 at 0.70 and FL4
at 0.400. The narrow filters are centered at either 1000 Hz (or 800 Hz
if the BFO range will not accommodate 1000 Hz for the 0.40 filter on
both sidebands). In operation, the RTTY signal is tuned to center on
1000 Hz (or 800 Hz) and the program will decode the signal -
transmission will occur at the same offset and noone on the receiving
end will know whether you are using real FSK or AFSK.
So the short answer is: the K2 will operate just fine on RTTY, and yes,
you can use narrow RTTY filters to minimize the QRM.
73,
Don W3FPR
John Tobias Croteau wrote:
How well does the K2 work in RTTY mode? I presume it is AFSK only? I
seem to recall that some do not recommend the K2 for serious RTTY
operating but I don't remember the reasoning behind this. I vaguely
recall reading this about 2 years ago from somewhere.
I'm a RTTY operator first then SSB. I've never been good with CW and
probably never will so I focus on these two modes. I know it's a poor
attitude but let's just not go there, at least I am honest about it.
Most of my RTTY operation is centered around contest weekends simply
because I can only operate portable due to antenna limitations at the
home QTH. However, I am not a hardcore contester. I merely operate
during the contests to maximize QSO numbers although getting a good
score never hurts.
Around August, I'm finally going to be able to upgrade to something in
the K2 price range. Will the K2 be acceptable for the way I operate
RTTY or should I hold out for a K3? I know the K3 will be a much
better data rig. I can't really afford a K3 but I could probably make
it happen.
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