I think the new Chinese roads, railways, ports and power plants across South-East Asian and African countries (all with large, prominent signs saying exactly who paid for them) are a more powerful projection of soft power than a shortwave radio station that is relatively listener-untroubled.
That would be more akin to 'hard power'. Soft power is more based on media and entertainment. Propaganda usually doesn't consist of highways and railroads. It consists of media, including news media. Entertainment is also a form of it at times -- even when unintended.
A classic example of it -- although our government doesn't intend it that way, is Hollywood, and even some of our other entertainment media. Hollywood exports a vision of the US that often is better than the reality. Sometimes it is much worse than the reality. Millions of people in other countries have inaccurate views of US society because of what they see in movies and TV. Millions of people all over the world are usually introduced to the US via Hollywood.
The US government doesn't have anything to do with it, but it's a form of 'soft power' just the same.
A Chinese example of 'soft power' in the US would be the paid-for, full page, full color articles printed in big newspapers like the NY Times in the 2010s, which looked like actual news articles, but were paid-for, Chinese propaganda. The number of readers to those articles were few, comparatively. The NY Times at its height maybe has had 2-3 million readers, and most of those never subscribed to the newspaper, or even read most of the articles, including the Chinese propaganda pieces.
But the feature, propaganda stories were an example of 'soft power'. The concept behind 'soft power' is that you are using various methods to influence people, and that number of people doesn't have to be large to make a difference in another country.
Internet comment bots could also be a form of 'soft power'. The number of people who are influenced by internet comment bots are relatively few, when compared to the entire population of the United States. But China (and Russia) use them for a reason. If a government can influence 5 people in a city, those 5 will influence maybe 10 others. And so on. You don't need a large number of people to gain influence in a society. The BBC doesn't broadcast to Africa every night because everyone in Africa is tuning to the BBC. They do it as a form of soft power.
Especially with China it its an example of a country or great power playing the long game, as opposed to the more short sighted one.