W7AY told me that there had been some discussion of the FSKit here. I
don't regularly read this reflector anymore so I appreciate the
heads-up, Chen. I'll try to answer a few questions.
1. There are no more FSKit PC boards available. After the QST article
on the FSKit came out last August I stayed busy for several months
sending out PC boards and programmed microcontrollers, but after the
first of the year (and several batches of PC boards) the demand had
been largely satisfied. I only provided these items as a service to
QST readers and just covered my costs. I have no plans to make a
commercial product and no plans to order more boards. The schematic
and parts list is in the August 2011 QST article, and the circuit is
dead simple to build.
2. I can still supply programed Atmel microcontrollers for anyone who
wants to build the FSKit. They are $5 each including shipping in the
US and $8 including shipping outside the US. The hex file for those
who want to program their own micros is available from the ARRL
website. The C source code is available for anyone who wants to make
modifications to the firmware and create a custom version.
http://k4dsp.homeip.net/~doug/fskit/
3. If someone believes there is sufficient interest and wants to make
a run of PC boards (or kits or products, for that matter) I'll be
happy to share the Gerber files with you. If you want to incorporate
the FSKit into some other product you could do that too. Contact me
directly for details.
4. The FSKit is not likely to work well if your ASFK program is
frequency-agile on transmit, (ie. you're using AFC and the transmit
tones follow it.) It will tolerate a few percent slop on the mark and
space tones, but it makes no effort to track changes in AFSK tones
sent from the sound card.
I have no interest whatsoever in the AFSK vs. FSK debate, really.
Suffice it to say that a good number of the folks who built FSKit
units had perfectly valid reasons for wanting to use FSK. I'd say the
majority of them have radios in which the narrow IF filters can only
be engaged in FSK mode. After that it was a mix of serial port, USB,
RFI, and operating system reasons.
73,
Doug K4DSP
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