📡 Overview of the CB Radio Japan–Taiwan Propagation Experiment
The CB Radio Japan–Taiwan Propagation Experiment (#PEC_JT) is an international, community-driven project that explores the feasibility of long-distance communication on the 27 MHz citizen band (CB radio) between Japan and Taiwan, strictly within the legal frameworks of both countries.
The project was proposed by Japanese low-power radio researcher Yasuo Kagaya (callsigns: Kashiwa FX886 / JP1MFV; operating in Taiwan as BW503KY). In early 2020, while living in Changhua County, Taiwan, he began the first transmission tests.
The initial setup used 26.975 MHz (1 kHz below Japan’s CB Channel 2), AM mode, and about 4 W output. Voice calls and Morse (buzzer) IDs were alternated so that even weak signals could be identified. On the Japanese side, stations could participate simply by monitoring with legal CB equipment (≤ 0.5 W), and coordination/reporting was organized on X (formerly Twitter) via the hashtag #PEC_JT.
The upper row shows the 40 CB radio channels under the FCC standard adopted in Taiwan, while the lower row illustrates the channel allocation of Japan’s citizens’ band (CB) radio. Notably, the second channel in both countries (Taiwan: 26.975 MHz / Japan: 26.976 MHz) differs by only 1 kHz, which makes cross-border communication (QSO) between Japanese and Taiwanese CB radio stations possible.
Although testing first focused on daytime paths, activity gradually expanded to night and early morning. Accumulated observations confirmed the effectiveness of F-layer propagation on this path, while Sporadic-E (Es) often obstructed the long-haul link. A key finding is that distances of ~1,900 km and beyond are favorable for F-layer returns at low takeoff angles. Multiple successful contacts over ~3,000 km have been reported even under the ≤ 0.5 W power constraint on the Japanese CB side.
On 14 March 2021, the project achieved its first formal two-way QSO between BW503KY (Taiwan) and Nagoya CE79 (Japan)—a major milestone. The same transmission was received widely across Japan, demonstrating the breadth of the propagation footprint.
Antenna Evolution of BW503KY
From left to right: In March 2021, a 1/4λ wire was directly connected to the transceiver. In the summer of the same year, it was replaced with a 1/2λ EFHW, and in 2022, it transitioned to a 1λ delta loop.
Support from Taiwanese collaborators has been crucial—especially James Tsao (155TW321 / BM3AUG) in Taoyuan City. Since 2021 he has served as a core transmitting partner and installed a dedicated #PEC_JT automatic beacon on 26.965 MHz, providing regular signals from Taiwan and greatly improving continuity for receiving experiments in Japan.
Overview of the 155TW321 Beacon
Operating frequency: 26.965 MHz
Modulation: A3E (CW)
Transmitter power: 1 W
Transmission site: Taoyuan, Taiwan
The left figure shows the beacon transmitter operated by station 155TW321, while the right figure presents reception records obtained in Australia.
By clicking on the images, reception videos can be accessed.
Notably, reception reports from Mexico have also been confirmed, highlighting the beacon as a valuable case study in the investigation of long-distance propagation characteristics.
https://www.facebook.com/groups/hfunderground/posts/961768095205593/?comment_id=961867068529029
In 2022, 155TW321 and BW503KY operated from the Keelung coast with a 2-element Yagi and just 0.8 W, successfully working stations across Japan. In 2023–2024, further activity came from Kinmen Island (a territory administered by Taiwan) by 155TW747 and 155TW023, expanding the geographic scope of observations and reinforcing the project’s continuity.
November 12, 2022 – Joint Operation of BW503KY and 155TW321
A joint operation was carried out by stations BW503KY and 155TW321 on the coast of Keelung, Taiwan, with a transmitter power of 0.8 W.
The video on the left shows the operating scene from the Taiwan side, while the one on the right presents the communication from the Japan side at the same time (with 0.5 W output).
Click on the photos to play the respective videos.
*Left: A map showing the location of Kinmen Island.
*Center: On November 16-17, 2024, station 155TW023 (back) and station 155TW747 (front) carried out a CB radio DX-pedition from Kinmen Island aimed at Japan. Click on this photo to watch the video of the event.
*Right: On August 23, 2025, at the Tokyo Ham Fair, a commemorative photo of an eye-ball QSO between ex-BW503KY Mr. Kagaya (left) and 155TW023 Mr. Lin (raight).
Beyond the technical achievements, the project blends radio and social media into a new style of collaboration: schedules are shared in advance, participants post real-time reception reports, and the excitement of successful contacts is celebrated together online—an emerging form of CB culture in the internet era.
The experiment continues today. CB enthusiasts in Japan and Taiwan make contacts on a daily basis, accumulating technical insights while fostering deep friendship and cross-border exchange.
🔗 Related Links
- View #PEC_JT posts on X (formerly Twitter)
- “Japan CBer Callbook” compiled by a Taiwanese CBer
- Taiwan CBer Call Sign Online Cork Board
📖 Related Publications (Bibliography)
The #PEC_JT project has been covered in the following Japanese publications:
- Denshi Kōsaku Magazine, August 2022 Extra Issue (Dempa Shimbunsha).
“Reiwa Edition: New BCL Manual”, published Aug 30, 2022.
Article: “Taiwan CB Operators Calling Japanese Listeners on 27 MHz”, p. 154. - Denshi Kōsaku Magazine, August 2024 Extra Issue (Dempa Shimbunsha).
“Reiwa Edition: License-Free & convenience radio Manual”, published Sep 5, 2024.
Article: Chapter 7 “Challenging DX: Communicating with Taiwan on CB Radio”, p. 128.
This article will be updated regularly.
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LoPRA Lab
📍 Published by LoPRA Lab (Low-Power Radio Research & Applications Laboratory).