AMSAT-NA Former President and pioneer of satellite and digital radio radio Tom Clark, K3IO (formerly W3IWI), of Columbia, Maryland, died on September 28 after a short illness and hospital stay. A member of ARRL Life, he was 82 years old. Clark’s achievements are legendary and he left a lasting mark in the world of amateur radio satellites and digital techniques.
“His long-standing technical achievements, mentoring others and technical leadership will be lacking in his many peers and friends around the world,” said Bob McGuire, N4HY.
In honor of Clark, AMSAT rebranded its upcoming annual collection as 2021 AMSAT Dr. Tom Clark, K3IO, Memorial Space Symposium and Annual General Meeting. It will take place on October 30 via Zoom. (AMSAT members may I register to attend through the AMSAT membership and event portal.) The event will be broadcast live on AMSAT’s YouTube channel.
Founder of Tucson Amateur Packet Radio (TAPR), Clark is the co-founder of the TAPR / AMSAT DSP project, which led to software-defined radio (SDR). He was a leader in the development of the AX.25 packet radio protocol. Clark served as the second president of AMSAT from 1980 to 1987. He also served on the boards of AMSAT and TAPR.
In agreement with McGwier, Clark developed the first amateur digital signal processing (DSP) hardware, including a number of modems. He developed receivers for uplink and spacecraft LAN (local area network) architecture used on all Microsats (AMSAT-OSCAR 16, Dove-OSCAR 17, WEBERSAT-OSCAR 18, LUSAT-OSCAR 19, Italy-OSCAR 26, AMRAD-OSCAR 27 and TMSAT-OSCAR 31). McGuire said it was Clark who convinced him in 1985 that the future lay in the DSP.
“We launched TAPR / AMSAT DSP [digital signal processing] project and it was announced in 1987, “said McGuire. “We have shown in our efforts that small stations with small antennas can bounce signals from the moon, and using the power of DSP, we can see the signals in computer displays.” This led to a software-defined transponder (SDX) for satellite operation, including ARISSat and AMSAT Phase 3E.
Clark received his doctorate in astrogeophysics from the University of Colorado. He continued to serve as head of the astronomical branch at NASA’s Marshall Space Flight Center and was a senior scientist at NASA’s Goddard Space Flight Center, where he was principal investigator in space long-range basic interferometry (VLBI).
In 2005, Clark became the first non-Russian to be awarded a gold medal by the Russian Academy of Sciences for his contribution to the VLBI international network. He was a member of the 2001 class. CQ Amateur Hall of Fame of the magazine.
In 2016, ARRL awarded the Clark with the President’s Award to recognize his 60 years of advancement in amateur radio technology. On this occasion, McGuire said: “There would be no AMSAT to inspire all this work without Tom Clark. Tom saved the organization and inspired us all to look to the future and strive for the stars. ”
Clark was a member of the American Geophysical Union and the International Geodesy Association.