We've got the 10 Meter RTTY Contest coming up this weekend, and
I'm trying to figure out the best way to do the RTTY Tx function.
I think the combination of switching to N1MM LoggerPlus, and
switching to 2Tone as primary decoder have raised some issues.
Here are some available options as I see them:
I could do AFSK, but I've grown accustomed to hearing the
915/1085 Hz tone pair, and apparently that's dangerous because
the harmonics fall into the 2.7 KHz passband of the SSB filter.
Can I get away with that tone pair? I'm using a K3 radio,
I love 2Tone for receiving, but apparently its FSK Tx is subject
to timing jitter if the computer is not a quad-core powerhouse.
My computer is pretty good, but not THAT good.
I have the parts lying around for G3YYD's deluxe pseudo-FSK
circuit, with the comparator IC. I could jump back onto that
project and probably get it done in time for the weekend.
The FSKit sounds like a good option, but apparently the circuit
boards and programmed controllers are no longer available. If
someone has one to sell, I'd like to hear from you.
I could use MMTTY for Tx. Apparently its FSK is not subject to
timing jitter? I could then use 2Tone in a separate Rx-only
window, but then I wouldn't see my transmitted text in that
window, which is unnerving. I could move my eyeballs between the
two windows for Tx/Rx, but that is suboptimal. Overall, this
sounds like the most certain approach though. Is MMTTY FSK
timing solid, even on a moderate-speed computer? I'm using a
real PCI serial port card.
Is there an inexpensive hardware modem that I could use for RTTY
Tx-only?
I would appreciate comments on the above options. If anyone has
a better idea, please let us know.
Many thanks.
Dave Hachadorian, K6LL
Yuma, AZ
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