What did the declassified documents reveal?

Cold Open: We're declassifying a CIA report from March 1968, detailing a probable SIGINT facility in China, codenamed Cheng-Yang. This document was released through The Black Vault and is now available on the CIA's reading room. The report is a photographic intelligence report, compiled by the National Photographic Interpretation Center. Provenance: This document was declassified through the CIA's reading room, with a declassification authority of CIA-RDP78T04759A008404010028-5. The document was approved for release by NIMA/DOD. The document is part of the ACIC series, with a scale of 1:200,000. The Document: EET hy, Oo CHENG-YANG PROBABLE SIGINT FACILITY CHINA copy... 3 PAGES 25X1 GROUP 1 EXCLUDED FROM AUTOMATIC DOWN GRADING AND DECLASSIFICATION Declass Review by NIMA/DOD Approved For release : CIA-RDP78T04759A008404010028-5 - . 25X1 Approved For Release RDP78T04759A00B400010028-5,-— 7 3¢g— 25X11 NATIONAL PHOTOGRAPHIC INTERPRETATION CENTER GEO COORDS FUNCTION 36-20~30N120~22-008 WAC BE NO INSTALLATION NAME Cheng~yang Probable SIGINT Facility, China LOCATION 2.5 nm north of Cheng-yang MAP REFERENCE 25X1A Document Reference: ACIC series, scale 1:200,000. NPIC TS 25X14 PHOTOGRAPHY REQUIREMENT NsA/S0C/R96-67 NPIC PROJECT LL Basic Operational Components: FIX BIGHT Triple FIX EIGHT in a triangular arrangement. Communications Facility containing 2 Rhombic antennas, 1 Fishbone antenna, 1 Vee antenna, and 8 Dipole antennas. TMAGERY ANALYSTS: The Cheng-yang Probable SIGINT pects includes a communications facility at BIGHT arranged in a triangular pattern centered at ers 120-21~ 30H, the component of which are designated B, C, and D on Figure 1; and an isolated FIX EIGHT at 36+20-l5N 120-20-58E which is designated E on Figure 1. The distances between the components of the facility are shown on Figure 1. The approximate dimensions and orientations of the antennas in the communications facility are shown on Figure 2 and are summarized in the table below. Because the azimuthal projections are approximate, the projections to determine possible correspondents would not be meaningful. ANTENNAS Number Type Dimensions , Orientation (in feet) eee 1 Rhowbic 5/265 2 Rhombic 100/280 25X1D 3 Vee 140/320 4 Dipole 25X1D > Dipole 75/255 6 Dipole 40/220 i" Dipole 70/250 8 Dipole 350/170 9 Dipole 330/150 10 Dipole — 300/120 11 Dipole 285/105 12 Fishbone 90/270 25R2bR1 Zimuthal projecvLons are a&pproximace, ~|[- Approved For Release guerre ii ROP 78704750000 A-LRDP78T04759A006840001 25X1 25X1 25X1D Context: The National Photographic Interpretation Center, now known as the National Geospatial-Intelligence Agency, compiled this report to analyze the probable SIGINT facility in China. The report includes a detailed description of the facility's components, including its antennas and their dimensions. Outro: This is what the public record looks like at its most ordinary, a declassified CIA report detailing a probable SIGINT facility in China. The document is available on…

Why was this case declassified?

This material entered the public record through the U.S. declassification and Freedom of Information Act (FOIA) process. The originating source document is linked on this page so the citation chain is auditable.

CIA Report From March 1968, Detailing A Probable Sigint Facility In China

◆ BLUF — The short version

Cold Open: We're declassifying a CIA report from March 1968, detailing a probable SIGINT facility in China, codenamed Cheng-Yang. This document was released through The Black Vault and is now available on the CIA's reading room. The report is a photographic intelligence report, compiled by the National Photographic Interpretation Center.

Date: AUG 8 · 2026
Release: Declassified · U.S. public record (FOIA)
Source document: View the primary source document

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What was CIA Report From March 1968, Detailing A Probable Sigint Facility In China about?: Cold Open: We're declassifying a CIA report from March 1968, detailing a probable SIGINT facility in China, codenamed Cheng-Yang. This document was released through The Black Vault and is now available on the CIA's reading room. The report is a photographic intelligence report, compiled by the National Photographic Interpretation Center.
Why was this case declassified?: This material entered the public record through the U.S. declassification and Freedom of Information Act (FOIA) process. Storyflo narrates it directly from the public release.

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CIA Report From March 1968, Detailing A Probable Sigint Facility In China

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