G1SLE.com - Projects in Amateur Radio |
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Last Updated: March 26 2021 17:51
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PSK31 Beacon

G1SLE Beacon Keyer Mk2
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The Mk2 beacon keyer is a self contained PCB roughly 90 x 65mm. The beacon texts are user programmable via
the RS232 serial port. The keyer generates AF tones for both PSK31 and RTTY. The audio tone output level is adjustable
up to 3v p-p. Beacons may be in 50 baud RTTY (170Hz shift) or PSK31. Full Varicode and RTTY Baudot (US) alphabets
including punctuation are supported.
As with most of my recent designs many of the components are surface mounted types. All resistors and capacitors are
in 1206 or 0805 suface mount packages, with the exception of the 2 x SIL resistor networks. As through hole mounted
components begin to become less available than surface mounted equivalents I have used surface mount packages for a number
of ICs. These are mostly the larger SOIC DIL types which are reasonably easy to manipulate and solder with standard hand tools.
The 89C51ED2 is in the common PLCC44 package, however since this part is fitted in a PLCC44 socket which is itself through hole
mounted the constructor has no need to solder to the device.
By using the 89C51ED2, a powerful derivative of the long established 8051, the component count is kept very low, resulting in
a compact simple design, capable of generating not only PSK31 and RTTY but also various other modes including .WAV file storage
and playback. Separate firmware to support additional modes will be released in due course.
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