Following on from the weak opening on the 29th of May, there was another 50 MHz opening between Europe and Australia on Monday the 31st of May 2021.
The above map from the PSK Reporter website shows the almost 15,000km path that was open for VK4MA on the east coast of Australia.
LY2BAW 6m FT8 14683 km 07:46:59
VK4ABW YL2CZ 6m FT8 12300 km 09:11:59
VK4ABW OG3G 6m FT8 12228 km 08:43:59
VK4ABW OH1MN 6m FT8 12199 km 08:44:29
VK4ABW OG2A 6m FT8 12147 km 08:43:59
VK4ABW LY2BAW 6m FT8 12144 km 08:46:57
VK4ABW OH7KM 6m FT8 12113 km 08:22:30
VK4ABW YL2II 6m FT8 12104 km 09:12:59
VK4ABW OH3SR 6m FT8 12091 km 08:22:26
VK4ABW YL2CP 6m FT8 12090 km 09:11:59
OH3JR VK4ABW 6m FT8 12081 km 08:36:44
VK4ABW ES5PC 6m FT8 11999 km 08:44:59
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UR0MC VK3OT 6m FT8 13989 km 06:02:11
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The longest path seems to have been between VK3ZL and SP4K in Poland at 15,459kms
UR0MC VK3ZL 6m FT8 14163 km 06:41:44
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Propagation Mode: We're back to the same question again... How do 50 MHz signals from Europe reach Australia near the bottom of the sunspot cycle?
The easy 'go to' answer was that it was multi-hop Sporadic-E, case closed.
The problem I'm starting to have with this is down to probabilities.
Take SP4K in Poland. What are the chances of one hop Sp-E in the direction of Australia capable of supporting a 50 MHz signal? It's late May, it's the Summer Sp-E season so it's pretty high.
Two hops?... What is the probability of getting two Sp-E regions spaced at just the right distance to allow a double hop at 50MHz? The probability is obviously lower.
Follow that same logic and apply it to 3 hops, 4 hops and so on. By the time we get to 15,459kms, we're probably looking at 8 hops.
What is the probability of getting eight Sporadic-E clouds capable of supporting 50 MHz spaced at just the right distance from each other... all the way from Europe to Australia?
And if that probability wasn't low enough, what then is the probability of 8 hop Sp-E on 50 MHz from Europe to Australia on two out of three days?
I think the probability is now so low that there must be some other answer. Perhaps TEP (Trans-Equatorial Propagation) from Australia to China accounts for a large part of it? Some other propagation mode?
I'm not sure the simple 'It must be multi-hop Sporadic-E' adds up anymore.
1 comment:
Hi John, I don't believe in the 8 hop sporadic-e theory as you say is very improbable for 2 out of 3 days in a row.
But there is plenty of evidence to suggest F2 is the probable propogation mode....
Although there is also the possibility of Tropo assisted sporadic-e connecting to China with then TEP to Australia.
Tropo conditions did seem to be good to the East.
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