A message in a specific format, likely related to amateur radio operations.

Breaking down the elements:

* `01:15` is the time of transmission.

* `JE1HMS/P` appears to be the call sign of the station that transmitted. In the Amateur Radio Union (ARSU) system used in Japan, "JE" indicates a Japanese mainland license. The "1" is likely the prefix for Saitama Prefecture, where Kasukabe City is located.

* `on JP-1899(Kasukabe Yumeno-mori Prefectural Park, JP-ST)` suggests that the station was operating from Kasukabe Yumeno-mori Prefectural Park in Saitama Prefecture.

* `50313.0` is the frequency used for transmission, in kHz (kilohertz).

* `FT8 QRT` indicates that the transmission was on the FT8 digital mode and has been stopped (`QRT` means "stop" or "quitted").

* `TNX NY QSO!` seems to be an expression of gratitude towards the operator who made a contact with this station, using the phonetic alphabet (e.g., "NY" for "November"). The "!" at the end is likely a celebratory punctuation mark.

This message appears to be a standard format used in amateur radio operations to inform fellow hams about transmissions and contacts.