Page 29 - EngineerIt June 2021

AMATEUR RADIO

The WSJT story - a story of weak

signal communication

mateur radio is like a bug - if it of their three-story Victorian farmhouse. “With one such project we managed to shear off
bites you, it does not let you go the brick chimney, flush with the roof, much to the consternation of our parents”, he recalls.
Aeven if you become a successful That incident was one of many practical lessons of his youth, often involving ill-advised
professor and a Nobel prize laureate. shortcuts toward some goal. In their school years, the two brothers filled most of the third
This is the story of Prof. Joe Taylor floor of their farmhouse with working ham-radio transmitters and receivers. Their rigs
who has made major contributions to were mostly built from a mixture of post-war surplus equipment and junk television sets.
radio weak signal communication. To They learned by experience that when high-voltage was needed, the power company’s
be passionate about amateur radio is 6000-to-120-volt transformers work admirably in reverse and most amplifiers will oscillate,
probably much like being a mountaineer, especially if that is not what was wanted.
always looking for a higher, more difficult Joe Taylor first obtained his amateur radio license as a teenager, which led him to
mountain peak to conquer. the field of radio astronomy. Taylor is well known in the field of amateur radio weak signal
Joe Taylor K1JT, as he is known communication and was assigned the call sign K1JT by the FCC.
in the amateur radio world, developed His amateur radio accomplishments have included mounting an ‘expedition’ in April
digital communication modes that 2010 to use the Arecibo Radio Telescope to conduct moon bounce (EME) with radio
operate well below the noise. His latest amateurs around the world using voice, Morse code and digital communications.
development is FT8 which has captured He has actively developed several computer programs and communications protocols,
the imagination of the amateur radio including WSJT (“Weak Signal/Joe Taylor”), a software package and protocol suite
community. The new mode is named that utilises computer-generated messages in conjunction with radio transceivers to
after its developers, Steven Franke communicate over long distances with other radio amateurs.
(K9AN) and Joe Taylor (K1JT). The
numeral designates the mode’s eight- Here is a glimpse of the programs he developed and which are freely available:
frequency shift keying format. WSJT-X, WSJT, MAP65, and WSPR are open-source programs designed for weak-
signal digital communication by radio amateurs. Normal usage requires a standard
Born to experiment SSB transceiver and a personal computer with soundcard, or the equivalent. SDR-style
Joe Taylor was born to experiment. hardware including the SDR-IQ, Perseus, SoftRock, and FUNcube dongle are supported
He was awarded the Nobel Prize by MAP65 and WSPR.
in physics in 1993 for the discovery
of a binary pulsar, which opened
up new possibilities for the study of
gravitation.
Pulsars are very compact stars
that radiate radio waves with very
regular variations. In 1974 Joe Taylor
and Russell Hulse discovered a pulsar
comprised of two stars in very close
proximity that rotate around each other.
Taylor and Hulse could demonstrate
that the stars’ radiation and movements
correspond with Einstein’s general
theory of relativity. Amongst other
things, this theory predicts that the
pulsar would emit energy in the form of
gravitational waves, which should result
in slowly declining intervals. Taylor was
able to confirm this in 1978.
Taylor’s fondest memories of his
youth are how, together with his brother
Hal, they erected numerous large rotating
ham-radio antennas high above the roof Joe Taylor in his radio room

EngineerIT | June 2021 | 27