After a quiet winter period, the ADS-B ducting is really going strong at present with the hot north to north westerly winds.
This mornings Delta DL17 service (N709DN B777-232LR) was picked up at 615.81 nm (1140.480 km) 57.5 Deg True (plot at top right of screen). This was just short of the 1,201.2km pickup back in March this year.
There were many other plots in the 400-450nm range also, some US and others Tasman services.