3K didn't had a logo until the first logo that was unveiled in 1991. Instead, some texts were used on idents and intros and were completely different and had a difference between the logo on the corner and the ident logo.
1989 (or until 1990)
The logo was "3K" written in a font similar to OCR A Extended, or else.
Logo uploaded here is a reconstruction.
1991-1995, 2000-2002, 2003
This was the first logo. This was then reused from after the October 5, 2000 revolution until early 2002 when the blue brick logo was adopted, and then again for a brief period in late 2003 when the last logo was introduced.
1992-1993
The logo had the "3K" on the top and "TVB" spaced on the bottom, because to represent the third channel of Radio Television Belgrade. All of the content were written in Latin because of most content that were maybe written in Latin.
RTS 3 (first era)
1993-1995
During this period, the RTS logo was used without additions such as a "3" or "B3".
1995-1996
During late 1995 (around the date where RTS logos got uniformed) and somewhere around early 1996, this uniformed logo was used. It matched the styles of RTS1 and RTS2 at the time it was used.
3K (second era)
1996-2000
While the red circle with a white "3" was used, this logo was only on the corner of the screen.
1997-2000
This logo was used mostly for idents and intros, and wasn't displayed in the corner of the screen like the rest.
In 2002 3K became RTS 3 and changed its logo to match the other two channels. "K" was left out and "RTS" was added before the 3.
3K (third era)
2003-2006
It didn't take long for "K" to get back. In 2004 a new logo was adopted, due to some issues with RTS. The logo was similar to the previous but with a yellow "K" and without the RTS letters. Two years after, 3K stopped broadcasting.
