It appears to be a radiotelegraphy transmission report in the amateur radio mode of operation. Here's a breakdown of the information:

* `05:58`: The time of transmission.

* `JF1CMH/1`: The callsign of the transmitting station, indicating that it is an amateur radio station in Japan (prefix "J") operated by JF1CMH and using a repeater or relay station with a suffix "/1".

* `JP-1304(Hodogaya Prefectural Park)`: The location of the transmitting station. In this case, it's Hodogaya Prefectural Park in Japan (denoted by "JP"), which is likely using an amateur radio license prefix and geographic identifier.

* `JP-KN`: This is not part of the transmission report, but rather a separate piece of information indicating the location or band being used. The letters "KN" could refer to a specific frequency band.

* `21045`: The frequency of transmission in MHz (megahertz).

* `CW`: The mode of transmission, which stands for Continuous Wave and is a form of radiotelegraphy where Morse code is transmitted using radio waves.

In summary, this report indicates that the amateur radio station JF1CMH/1 was transmitting on frequency 21045 MHz in CW mode from Hodogaya Prefectural Park in Japan at 05:58.