12,000km opening between Australia & California - 27th Dec 2021

Monday 27th December 2021: It was interesting to see that there was a recent opening on the 50 MHz band between the SE of Australia and southern California. Unlike openings from Australia to South America, this one crossed the equator and went to North America.

There is a very active group in Australia & New Zealand using the WSPR beacon mode and on the 27th of December, VK2IJM and VK2EFM in New South Wales heard N3IZN in California.

 UTC (y-m-d) TX txGrid RX rxGrid                         MHz         W SNR drift km 
2021-12-27 01:16 N3IZN DM13ji VK2IJM QF56ni 50.294549 100 -24 0 12115 
2021-12-27 00:52 N3IZN DM13ji VK2EFM QF56oq 50.294554 100 -18 0 12091 

The distance was just over 12,000kms.

Propagation Mode?? The first most obvious answer is that it was multi-hop Sporadic-E but I suspect the reality is more complex that that. The signal path crosses the TEP zone around the equator so that may have had some impact. The solar flux is up around 120 and the MUF is now above 30 MHz most days. Is it reaching 50 MHz near the equatorial region?

Western Australia to Europe?? The example above was just over 12,000kms, that is the same distance from the west coast of Australia to the south-east of Europe. Are there openings between Europe and Australia on 50 MHz at the moment?

3000km+ opening on 144 MHz between Australia & Fiji - 9th Dec 2021

As the Summer Sporadic-E season begins in the southern hemisphere, there have been reports of openings on the 50 MHz and 144 MHz bands.

In Australia, there is a very active community of stations using WSPR beacon mode on the 2m and 6m bands with a lot of success. On the 9th of December, the 144 MHz WSPR signal from VK2IJM near Sydney was heard almost 3200 kms away on the island of Fiji by 3D2TS.

UTC (y-m-d)        TX         txGrid  RX         rxGrid MHz W SNR drift km
2021-12-09 23:08 VK2IJM QF56ni 3D2TS RH91fv 144.490586 20 -29 -1 3218 

As you can see from the single reception report, the signal was -29dB which is an incredibly weak signal.

The two stations tried to complete a FT8 contact just 14 minutes later. 3D2TS on Fuji could hear VK2IJM at-21dB but 3D2TS wasn't strong enough in Australia to complete a contact.

Propagation Mode???... The next question is how did a 144 MHz signal get from Sydney to Fiji? The maximum distance for one hop Sporadic-E is about 2300kms so something else has to account for the additional 900kms.

It's probably no accident that this happened over a sea path and the most likely explanation is a combined one hop Sporadic-E signal that coupled into a marine duct over the ocean. The above tropo forecast map from Pascal, F5LEN certainly supports this theory.

It's not possible to completely rule out a 100% marine duct or a chordal hop Sporadic-E opening with two Sp-E clouds but the highest probability is a combined Sp-E / tropo duct.

Links...

1) Check out my 144 MHz page for details of more 3000km+ openings.

3200km opening on 144 MHz in Australia - 15th Dec 2020

 

During an extensive Sporadic-E opening in Australia on the 15th of December 2020, WSPR signals from John VK2IJM and David VK2DVM in Sydney were heard by Peter VK6KXW near Perth in Western Australia.

Timestamp UTC   Call MHz SNR Drift Grid Pwr Reporter RGrid km az Mode
2020-12-15 10:36 VK2DVM 144.490519 -25 0 QF56og 10 VK6KXW OF87jr 3199 263 2 
2020-12-15 10:16 VK2IJM 144.490507 -8 0 QF56ni 10 VK6KXW OF87jr 3192 263 2

The path was in the region of 3200 kms which is way beyond the usual 2300km or so one hop distance from Sporadic-E. It seems likely that on this occasion, the most likely propagation mode was double hop Sporadic-E which is very rare at 144 MHz.

It looks as if just one WSPR transmission from each of the VK2 stations was decoded at 10:16 and 10:36 UTC. This was about an hour after sunset in Sydney which is 11 hours ahead of UTC.

It's also worth pointing out that the reports from the WSPRnet website say that the VK2 stations were running just 10 watts.

Tropo?... As the path cross the Great Australian Bight, it's always worth checking to see if that was a factor.

The forecast was for some weak tropo across the Bight but nothing special and it doesn't seem to extend inland.

VK6CPU in Perth was also heard by VK5AYD in Adelaide at around the same time over a distance of 2149 kms which was likely to be via Sporadic-E.

Timestamp UTC Call MHz    SNR Drift Grid Pwr Reporter RGrid km  az Mode
2020-12-15 10:56 VK6CPU 144.490510 -24  3   OF78wb 5  VK5AYD  PF97ja 2149 99  2 

It would seem as if double hop Sporadic-E was the most likely mode of propagation.

Update: Just to clarify that when I say double hop Sporadic-E, I am referring to two areas of ionisation that are capable of supporting 144 MHz propagation. The signal may well be chordal i.e. Ground to cloud to cloud to ground ... as opposed to reflecting off the ground at some mid way point.

Links...

1) More info about long distance openings on 144 MHz can be seen on my 144 Page... https://ei7gl.blogspot.com/p/144-mhz.html