Dr. Gerald N. Johnson — KE0KI
The Engineer in the Room
Most online technical communities have enthusiasts, experienced hobbyists, and the occasional retired technician. Very few have a licensed Professional Engineer with a Ph.D. in electrical engineering who shows up regularly, reads the schematics properly, and tells you exactly why your proposed solution is incorrect — and what the right one is. The R-390/R-390A reflector had Dr. Gerald N. Johnson, and the difference it made to the quality of technical discussion is hard to overstate.
The Man Behind the Callsign
Gerald Johnson was born in St. Louis, Missouri in 1942. He won a four-year scholarship and a National Merit Scholarship to Washington University in St. Louis, graduating in 1963. After moving to Iowa, he attended Iowa State University, earning his Master’s degree in electrical engineering in the late 1960s. In 1967 he was drafted into the U.S. Army and served stateside at a research laboratory in Virginia, working on the development of night vision technology — an assignment that suited his analytical temperament and gave him early exposure to precision military electronics. Discharged in 1969, he returned to Iowa State and completed his Ph.D. in electrical engineering in the early 1970s. He then passed the Professional Engineer examination and opened a consulting practice.
His consulting work included litigation support — he testified in court proceedings as a technical expert, the same role he would quietly play for a generation of R-390A owners who needed someone to actually work through the engineering rather than rely on forum opinion. He was a member of Sigma Xi, the scientific research honour society, and the Story County Amateur Radio Society in Ames, Iowa — where he also built the repeater duplexer from a collection of cavities he picked up at a Cedar Rapids hamfest for $150 the lot. He later relocated to Ozark, Missouri, where he was licensed as KE0KI.
The Reflector Presence
Dr. Johnson signed his reflector posts consistently as “Dr. Gerald N. Johnson, electrical engineer” or “Dr. Gerald N. Johnson, P.E.” — not as a formality, but as a signal to readers about the basis on which he was speaking. When he told you the neutral wire must never be broken, that wasn’t operating lore; it was National Electrical Code and the physics of floating voltages, explained in terms that made the hazard impossible to dismiss. When he told you the LM317 needs a heat sink sized for cold-filament inrush current, he had calculated it.
His contributions span virtually every technical domain touched by the r-390a.net “Pearls” archive documents. The power supply and AC safety material is saturated with his posts: GFCI behaviour with the original line filter, proper grounding polarity on the three-wire cord conversion, electrolytic capacitor formation voltages, inrush limiting, and the thermal limits of solid-state ballast replacements. The IF deck and filter discussions carry his analysis of why EAC’s use of Clevite ceramic filters instead of mechanical filters was technically defensible in contractor language even if it was commercially motivated. The antenna compilation includes his frank assessment of beverage antenna limitations and his preference for long vertical loops over the single-wire alternatives most owners defaulted to.
What distinguished Gerald from most reflector contributors was not just depth, but reasoning style. He did not argue from authority or experience alone. He stated the physical mechanism, derived the consequence, and let the logic stand on its own. When he disagreed with a proposed circuit — and he did, regularly — he explained what the failure mode was, not just that it was wrong. Other contributors appreciated this even when their own suggestions were being corrected; a clear technical explanation closes the debate more cleanly than conflicting opinions ever can.
Hollow State News and the 6082 Regulator
In the Spring 2001 issue of Hollow State News (Issue #52), Dr. Johnson published a detailed voltage regulator article for the R-390/URR and R-391/URR — solid-state replacement circuits for the 6082 regulator tubes that are a perennial maintenance challenge in these sets. The article emerged from collaborative analysis with Barry Hauser and others on the reflector, but the engineering design was Gerald’s. Community members building the replacement module referenced the article directly, noted they were “not an engineer” themselves, and made a point of saying they intended to contact Dr. Jerry with related technical questions before proceeding. The article’s credibility rested entirely on his professional standing.
The R-390 (non-A) with its 6082 voltage regulators presents design challenges that the R-390A bypasses entirely with its different regulator architecture. Gerald’s willingness to engage both variants, compare their stability characteristics, and develop practical solid-state solutions for the harder case reflected both his breadth and his commitment to the community’s full receiver inventory — not just the more common A variant.
The Technical Reference
Dr. Johnson is named as a contributor in both the original 21st Century R-390A/URR Technical Reference and the 2007 revised edition edited by Perry Sandeen. He is listed alongside Roger Ruszkowski, Hank Arney, Joe Foley, and others who provided substantive technical input to what became the definitive community-produced documentation for the receiver. His contributions to that document drew on the same well of analysis that characterised his reflector posts — grounded in circuit theory, tested against measurement, and written to be useful to someone actually working on the bench.
Legacy
Gerald Johnson brought something to the R-390 community that it could not have generated internally: the perspective of a licensed, practising electrical engineer who had spent a career solving real-world power and control problems. When he wrote about voltage regulation, he had designed voltage regulators professionally. When he wrote about electrical safety, he had investigated accidents and seen the consequences. When he worked through a circuit problem on the reflector, he was applying the same tools he used for paying clients.
That level of applied expertise, offered freely across years of reflector activity, elevated the technical baseline of the entire community. Restorers who read his posts carefully came away with a clearer understanding of how the receiver actually worked — not just what procedure to follow, but why the procedure was correct. That understanding persists in the archive, available to every new owner who finds their way to the Pearls documents and works their way through them.
Mike Peace VK6ADA / r-390a.net Administrator