@Gollevainen
Thank You for the suggestions, my source is indeed "Sokolnaya Okhota", but I have to admit that I am somewhat unconvinced.
1) Kolonka - problem is, that there already
is one Kolonka behind the mainmast, and with much better observation arc. Also, on the source drawing both devices are of very uneven size.
2) A-220 - that possibility seems more likely, but the source is quite vague (and source picture of rather low quality), that it looks quite similar to AK-176 as well. And since I know of
one, very blurry photo of A-220 (as opposed to current A-220M), trying to draw it
accurately would be
highly challenging.