Park, 20 km east of central Melbourne, and did some further research into
the HF Daytime Asian Summer Mode phenomenon.
As I had suspected, this mode now appears shortly after 0400 UTC (2 pm
Melbourne Standard Time), with sudden arrivals of strong signals on 7 MHz
and 9 MHz from transmitters in the Asian region.
In previous years, the mode became evident soon after 0200 UTC (noon local
time) - the whole thing seems to have been time-shifted by two hours!
Some signals stay for only a few seconds then vanish - others remain
audible for longer periods before disappearing.
These signals follow totally daylight paths!
Channel occupancies today included:
7270 MALAYSIA RTM-Kuching, carrying the "Waui-FM" network 0415 to 0435\
7290 INDONESIA RRI-Serui, local programming 0426 to 0440
7295 MALAYSIA RTM-Kajang, carrying "Trax-FM" English service 0415 to 0500
7380 INDIA AIR-Chennai regional program 0415 to 0430* (very rare never
observed previously !)
9635 VIETNAM VOV East Sea nat net 0415 to 0500
9730 BURMA BBS-Rangoon, Burmese 0430 (sudden appearance) to 0445
9750 MALAYSIA VOM-Kajang, Malay, super strong *0400 Malay
9835 MALAYSIA RTM-Kajang, carrying "Sarawak-FM" network originating in
9850 VIETNAM VOV nat net 0415 to 0500
9870 INDIA AIR nat net 0420 to 0430
9875 VIETNAM VOV dialects network *0400 to 0500
More research needed to track Indian regional services on 7 MHz, such as
Chennai 7380, with their local morning transmissions in the 0200 to 0400
Regards from Melbourne!