Well I am slightly sceptical myself, but I may have heard my first international contact from the USA.
I was scanning on the UHF frequency and the radio stopped at 433.020Mhz. The person talking was trying to see if anyone was out there, but was getting no answer so sign off with his call-sign KO6HW. He was from California USA (apparently).
When he went, I then heard someone chatting for a longer time on 433.080Mhz but I missed his call-sign as he said it to quickly, but he said he was in Adelaide. The only Adelaide I know is in Australia. So maybe the conditions were right, or they were not where they were meant to be. But as it was 2 different people, giving their call-signs, on 2 different frequencies, I am inclined to believe them.