June 24 1970 Concord Transcript — “Ham Radio Test Slated”

 

June 24 1970 Concord Transcript — “Ham Radio Test Slated”

Date: June 24, 1970
Location: Concord / Walnut Creek / Mt. Diablo, Contra Costa County, California
Motif tags: [Mt. Diablo] [Phillips Petroleum] [Signal / Transmission] [Ham Radio] [Z32]
Source: Concord Transcript, June 24, 1970, p. 17 — “Ham Radio Test Slated”
Archival citation: Newspapers.com
CHS Cross-Links:
• Spatial Axis: Mt. Diablo as Communication and Cartographic Hub
• Temporal Symmetry: June 24 → June 26 1970 (Z32 / Phillips 66 Map)
• Motif Echo: Energy → Signal → Geometry (Phillips Petroleum → Mt. Diablo → Zodiac Map)

 

 

Motif — Transmission, Power, and Encoded Signal

The Concord Transcript article of June 24, 1970 documents a planned Mt. Diablo field operation by the Mt. Diablo Amateur Radio Club as part of nationwide “Field Day” exercises concluding Amateur Radio Week. The article emphasizes portable transmission, generators, antennas, and two-way shortwave communication across the United States and Canada.

Of particular note is the explicit mention that Phillips Petroleum Company donated gasoline to power the generators used for transmission. This detail anchors the article within a motif of energy → signal → geographic elevation, a triad that later reappears symbolically in the Zodiac’s June 26, 1970 mailing containing the Phillips 66 road map and Mt. Diablo crosshair.

Within the CHS model, this establishes a media-visible instance where Phillips, Mt. Diablo, and technical signaling converge immediately prior to the Zodiac’s cartographic cipher.

 

Space — Mt. Diablo as Elevated Communication Node

Mt. Diablo functions here not as a crime scene, but as an infrastructure summit — a place selected for its altitude, line-of-sight reach, and symbolic centrality within Northern California.

The article situates the activity within Contra Costa County, while referencing coordination across national borders. This spatial framing reinforces Mt. Diablo’s role as a hub of transmission, echoing its later use by the Zodiac as the geometric center for his Phillips 66 map and angular instructions.

The meeting location of the club — the Red Cross Building on Ygnacio Valley Road in Walnut Creek — further situates the event within a corridor of civic, emergency, and infrastructural authority.

 

Time — Late June 1970 as Signal Prelude

The article was published June 24, 1970, two days before the Zodiac’s June 26, 1970 postmark of the Mt. Diablo cipher and Phillips 66 map.

This short interval is critical. It establishes a temporal relationship between:

• a publicly reported Mt. Diablo transmission event powered by Phillips Petroleum, and
• a cryptic mailing that prominently features Phillips branding and Mt. Diablo geometry.

The proximity in time suggests not causation, but contextual availability — the sort of environmental media signal that a parasitic communicator could absorb, echo, or weaponize symbolically.

 

Addendum: Temporal Symmetry

Researcher Richard Grinell has previously noted the one-month symmetry between the Zodiac’s June 26, 1970 Mt. Diablo cipher/map mailing and the July 26, 1970 “Little List” letter featuring the crosshair and 229.2° grid-north angle. The July 24, 1970 Kathleen Johns letter, which introduces the “little list” phrasing, has often appeared temporally anomalous within that sequence.

The June 24, 1970 Concord Transcript article restores a comparable symmetry on the earlier end of the timeline. It precedes the June 26 mailing by two days, just as the Kathleen Johns letter precedes the July 26 mailing by two days. Read this way, both months exhibit a similar cadence: a contextual or narrative prelude followed by a comprehensive Zodiac communication.

This observation does not imply coordination or foreknowledge by any party mentioned in the newspaper coverage. Rather, it highlights the offender’s apparent sensitivity to timing, rhythm, and calendar spacing — features that recur throughout the Zodiac correspondence.

 

Note

The Concord Transcript clipping demonstrates that Mt. Diablo’s association with signal transmission, technical coordination, and Phillips Petroleum was not retroactively imposed by the Zodiac, but already present in the public media environment days before the June 26, 1970 mailing.

Read through the CHS framework, the document occupies a clear triple coordinate:

1. Motif – energy, transmission, elevation, and signal;
2. Space – Mt. Diablo as infrastructural and symbolic hub;
3. Time – late June 1970 as a preparatory echo to the Zodiac’s cartographic cipher.

 

Closing Assessment

This newspaper clipping stands as a primary-source artifact demonstrating how publicly reported infrastructure and communication events can be mirrored, distorted, or ritualized within criminal correspondence. Like the 1924 Wisconsin “Little List/Mikado” advertisement, it shows how ordinary media language and civic activity can later reappear as symbolic scaffolding in the Zodiac’s performative system.

Together, these documents strengthen the CHS archive’s core premise: that the Zodiac did not invent his symbols in isolation, but harvested them from the ambient media field, transforming signal into threat and geography into stage.

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