If memory serves me correctly, tonight starting at 1900z, for 2.5 hours, is the August leg of the RSGB's activity contest on 70cm. I had to miss last month as we were on holiday. I only have a 2m halo and 5W but still manage to work some reasonable ranges especially towards the Midlands. Usually I am active for about 40-60 minutes maximum because of my poor voice. This is usually my limit.
UPDATE 1936z: With just 1 QSO and dire conditions, I gave up! Even G4CLA in the Midlands was weak: usually I manage to work him despite my 5W and 2m halo.