Hi, Peter - Welcome.

[SQ5AZK]

Hi;
Here, Peter, I'm from Minsk Mazowiecki.
Also often perceive radiosonde.
Too little writing in English
(All in Slovak)
because I use the automatic translator.

I have info for you at the beginning of our relationship:

3 frequencies used by Kaliningrad (for radiosondes)
401.490, 402.020, 404.020MHz.

Of course, every day I receive radiosonde with Legionowa
(WMO 12374)

I greet you cordially.
Peter, SQ5AZK.