Showing posts with label VK3EW. Show all posts
Showing posts with label VK3EW. Show all posts

Thursday, July 25, 2019

Unusual 50 MHz opening from Australia to Europe - Wed 24th July 2019

Over the last few weeks, there have been multiple openings from Europe to Japan at 50 MHz as stations make use of digital modes like FT8 to dig weak signals out of the noise. Most of these contacts are in the region of 9,000 to 10,000 kms which suggest multi-hop Sporadic-E was the likely propagation mode.

On Wednesday the 24th of July 2019, there was a very unusual opening on 50 MHz between Europe and New South Wales in SE Australia.

Here are some of the send/receive reports from PSK Reporter for the Australian stations on the 50 MHz band...

VK3ZL...

A successful FT8 contact was made between VK3ZL and EI3KD in Ireland, a distance of 17,375 kms. This seems to have been the longest contact of the day.

VK3BD...

VK3ANP...

VK3ZYC...

VK3EW...

The opening from Europe to SE Australia seemed to be from about 07:09 UTC to about 08:20 UTC.

The graphic below shows where the sun was shining at 07:30 UTC.


The opening seemed to coincide with sunset in SE Australia.

Some notes....
1) Solar..... The solar flux was way down at 67, the sunspot number was zero and there was no sign of any type of enhancement due to a flare. It's hard to imagine there was any normal type F2 propagation which might be seen around the peak of the sunspot cycle.

2) Japan..... The opening from Europe to Australia seemed to coincide with an opening from Europe to Japan. S57RR in Slovenia was on the send/receive list for five of the six VK3 stations and this is what the 6m map was like for him on the 24th...



3) Multi-hop Sporadic-E ???.... The distances worked from Europe to Australia were in the region of 16,000 to 17,400 kms. If it was simple multi-hop Sporadic E, it would require something like eight to nine hops. What are the chances of this many Sporadic-E hops? I find it hard to believe it's possible.

4) Winter..... It's worth noting that it's winter in Australia and this is not their Sporadic-E season. There seems to be no sign that the VK3 stations were hearing any other stations via Sporadic-E, just the opening to Europe.

Theory?...... Just a thought and I'm putting it out there for others to consider. Is it possible there was TEP (Transequatorial propagation) opening from SE Australia to an area SE of Japan and then became skewed via Sporadic-E? The multi-hop Sporadic-E opening from Europe also got to this region in the Pacific?


It's possible the TEP path may have been a bit more westerly from Australia to an area closer to China.

Perhaps it's grasping at straws for an explanation but I find it just as feasible as expecting 8-9 Sporadic-E hops to line up in a row at 50 MHz for the shorter direct path.

The key difference between the two paths would of course be if the beam headings for all parties were the most direct short path ones or if they were skewed. Unless someone is using a long Yagi, it may not be so obvious at 50 MHz.

All good material for debate of course but probably impossible to prove one way or the other.

Addendum : See message below from Brian, VK3BD (Added 12th Aug 2019)...