Starview 4 rf output is buzzing, please help!

I have connected a cable from the rf output part of the starviw box to another tv up stairs, but 4 some reason or other there is an awful buzzing noise but it has a perfect picture. Any suggestions would be appreciated, thx in advance.

 

i had a low frequency hum once, found it was to do with the splitter on my cable so i experimented with switching the cables around on the splitter and it ceased. make sure it's not that

 

Have checked that thanks 4 the suggestion, any other ideas?

 

dunno - if it defo happening because of the RF out? would suggest a process of elimination, all i can recommend from here myself