In the 1940s, estimates put the number of churchgoing Christians in the North Korean capital of Pyongyang between 25 and 30 percent of all adult residents. Though it’s impossible to get an accurate count given the Kim regime’s strict controls on information, after decades of oppression, the United Nations in 2014 cited estimates that the number of Christians living in North Korea was then between 200,000 and 400,000, or around 1 percent of the country’s population.

But South Korean Christian groups like FEBC cannot meet them, or potential converts, face to face. Tourist visits to North Korea are closely chaperoned by state-employed guides, and proselytizing is prohibited. The station has settled for what it sees as the next best thing: reaching the curious through illicit radio receivers.

FEBC buys handheld radio receivers and gives them to Christian organizations that work with smugglers to get the radios into North Korea so residents can secretly listen to the station’s broadcasts. Chung Soo Kim, who has for more than 20 years been a radio host for FEBC, where he translates California pastor Rick Warren’s sermons, estimated that the company has purchased “tens of thousands” of receivers over more than two decades. He said he recognized that while simply owning a radio is not necessarily risky, smuggling the radios into North Korea, or being caught listening to FEBC, can be dangerous. He justified the station’s distribution methods by saying that the smugglers know the risks of these missions, and they choose to carry them out anyway. FEBC sometimes donates receivers to organizations that send them over the border by balloon, rather than using smugglers on foot. (Secular human-rights organizations run similar smuggling operations to expose North Koreans to foreign movies and television.)

Because the radios are not pre-set to any specific channel, recipients of the radios can choose which stations they want to listen to. Chung Soo Kim said FEBC does not encourage North Koreans who listen to its programming to share their faith with others under the current regime. “We just want to share the Christian gospel with them. We don’t want them to put themselves at risk by openly claiming that they are Christian in North Korea.” He added that although the North Korean government has attempted to jam its signals, “financially, they cannot afford to jam our broadcasts. They do not even have enough food to feed their own people.”

The station has indications from defectors’ testimonies and listener feedback that its broadcasts are reaching their destination. Sookook Kim, who works in the feedback department, said correspondence from North Korean listeners is rare because of the risk involved in sending it, but arrives occasionally. She recounted one letter from a Christian living in North Korea who listened to the company’s broadcasts under a blanket at 4 a.m., the only time that listener deemed it safe to do so. The listener meticulously copied down pages of sermons and Bible passages and sent the papers to the station with a monetary offering. “It was so touching for us,” she said. “If we don’t receive these kinds of materials, it’s hard to have faith that they are really listening to FEBC Korea.”