It appears to be a radio transmission in the amateur radio service. The format is typically used by amateur radio operators to identify themselves and their location.

Here's a breakdown of what each part of the message means:

* `00:39`: This indicates the time of day when the message was transmitted.

* `JQ3JUK`: This is the call sign of the amateur radio operator who transmitted the message. In Japan, amateur radio operators use a unique combination of letters and numbers to identify themselves.

* `JP-1628(Iwakisan Prefectural Nature Park)`: This indicates the location from which the transmission was made. The "JP" prefix indicates that it's in Japan. The number "1628" likely refers to a specific geographic coordinate or grid square, but without more context, it's hard to say for sure. The mention of "Iwakisan Prefectural Nature Park" suggests that the operator is transmitting from within this park.

* `14074 FT8`: This indicates the mode and frequency being used by the amateur radio operator. In this case:

+ `14074` is likely the frequency in kHz, but it could also be a specific band or mode identifier (FT8 is a popular digital mode).

+ `FT8` is the digital mode being used for this transmission. FT8 stands for "Fast Hopper 8," which is a type of digital modulation scheme commonly used by amateur radio operators for weak-signal work and contests.

So, in summary, someone with the call sign JQ3JUK is transmitting from within Iwakisan Prefectural Nature Park in Japan using the FT8 mode on frequency 14074 kHz.