When North Korea launched a modernization of its broadcasting network in 2011, the Chinese company chosen to supply new TV and radio transmitters to the country faced a problem.

The location of broadcast towers in North Korea is so much of a state secret that engineers from the company weren’t permitted to travel to the DPRK to help install the transmitters, the company, Beijing BBEF Science and Technology, said on its website.

Instead, eight North Korean engineers spent a month in China being trained on how to install and operate the devices, which included a medium-power TV transmitter, several shortwave radio transmitters and a powerful mediumwave (AM) radio transmitter.

Our company supplies North Korea with 10kW [kilowatt] TV transmitter, 20kW/50kW/100kW/150kW SW radio transmitters, 600kW MW radio transmitter, together with the accessories. — BBEF website in English

The training ran from June 1st to June 27th last year.

On June 24 a ceremony was held (pictured, above) marking the training. BBEF listed the attendees as: President Zhao Baoshan, Party Committee Secretary Zu Wei, Vice President Ye Jin, and North Korean trainees.

Firstly, President Zhao Baoshan congratulated to the trainees on what they had learned and appreciated their performances. Then Vice President Ye Jin gave a short speech, praising the progress made by these technicians. North Korean expressed gratitude for the training and mentioned their wishes for further cooperation with BBEF. Last but not least, Party Committee Secretary Zu Wei and Vice President Ye Jin awarded the interns with Certificates of Completion. — BBEF website in English

Perhaps it’s an indication of the importance of propaganda and the government’s official media system that it’s not willing to allow outsiders to travel to the transmitter locations.

Recent monitoring of North Korean radio transmissions does indicate the installation of a new radio transmitter on 11680kHz shortwave. Previously the broadcasts on 11680kHz, like some other North Korean domestic radio transmitters, wandered a little either side of their assigned frequency but they are now observed to be exactly on 11,680kHz.

While the location of the transmitters might be a secret inside North Korea, that’s not quite the same outside of the country. Thanks to the satellite images on Google Maps and other mapping services, the location of most transmitters has already been found.

Here’s a look at the Kujang shortwave relay station used for transmitting Voice of Korea programming worldwide. Other sites can be found in Curtis Melvin’s North Korea Uncovered Google Earth overlay.