The ‘Warbler’

80M PSK31 Transceiver Board Kit







This project was introduced in 2000, the result of a breakfast table ‘bull-session’, complete with notes scribbled on paper napkins. The New Jersey QRP Club kitted and sold nearly 2000 of these before ‘burning out’. All proceeds benefitted the club and underwrote the ‘Atlanticon’ convention proceedings for a number of years.


The kit grew out of the observation that the PSK31 ‘watering hole’ on 80M (3580+ kHz) coincided nicely with the widely-available and inexpensive 3.579 MHz (color-burst) crystal frequency.  The Warbler is functionally a fixed-frequency SSB transceiver- its passband is 3580-3581 kHz.




Board size:  2.9” x 4.5”

3W PEP Output, 50 ohm load

3 computer interfaces:

Audio In (Sound card out)

Audio Out (Sound Card Mic In)

Serial Port (DB-9, uses RTS discrete) T/R Switching


Power reqmts:  12-15V DC at 0.5A


The Warbler board kit includes all on-board parts (as shown above) and assembly instructions . The instructions are the original masterpiece compiled by the NJ QRP Club and contain a wealth of operating tips, technical information and just plain excitement!


QSO with WA3REY.jpg


The screen shot above was captured from a QSO made during Warbler development.  [The noise at the right edge of the ‘waterfall’ is atypical. At that time, I lived about 2 miles from ARRL headquarters- that’s phase noise from its W1AW code practice transmissions.]   With a full-sized dipole antenna, solid-copy communication distance with the Warbler is 300 miles- not bad for a couple watts! 


A companion enclosure kit is not available for this board kit. For the diehard builder, the LMB 139 enclosure (Mouser Electronics or DigiKey Electronics) is a good fit.  The instructions include a sketch of connector hole placements for that enclosure.


Dave Benson, K1SWL

March 12, 2010