Opening on the 40 MHz band between Slovenia & South America - 16th May 2022

Borut, S50B in Slovenia reports that on the 16th of May 2022, his FT8 signal on 40.680 MHz was heard for the first time in South America!

The map above shows the path from S50B to PY2XB in Brazil (~10,000kms) and LU5FF in Argentina (~11,300kms).

Borut's 40 MHz was also heard by EA8BFK in the Canary Islands (3095kms) on the 11th and the 17th of May.  I don't know if the path to EA8 was open on the 16th but it does suggest the F2 layer propagation might be reaching as high as the 40 MHz band on north-south paths on a regular basis.

As there have been reports of recent openings on the higher 50 MHz band from Europe to South America, it should be no great surprise that there was an opening on the lower 40 MHz band.

I'd suggest however that this shows how valuable the 40 MHz band is to radio amateurs and to those interested in propagation research. Signals on the 40 MHz band give an early warning of potential openings on 50 MHz as the Maximum Usable Frequency (MUF) will often be just below 50 MHz. If someone hears a 40 MHz signal then at least they know what direction an opening might be likely.

It's also good to see some of the radio amateurs in South America getting interest in the 40 MHz band. It will be interesting to see if they report on any openings to the experimental stations on the 40 MHz band in North America.

Links...

1) As always, plenty of info on my 40 MHz page.

Long path opening on 50 MHz between South America and Asia - 12th March 2022

12th March 2022: There seems to have been a really good opening on the 50 MHz band at about 01:00 to 04:00 from South America to the east of Asia (Thanks to N0JK on the tip off for this).

The map above from the PSK Reporter website shows the paths as reported for PY2XB in Brazil. The site shows the shortest path between two stations but I think in reality, the contacts from Brazil to Japan & Taiwan were all via long path.

Long Path V Short Path... The map above shows the situation. For someone in the south of Brazil, Taiwan is effectively the other side of the world and there isn't that much difference between short path or long path.

I'm subject to correction on this but I think this extensive opening on 50 MHz was around 21,000kms via the long path.

The map at the start of the post shows that there was a path also from Brazil to Hawaii at 01:58 UTC. The map above also shows where the daylight was at about 03:00 UTC. It was likely that there was strong TEP to the west of South America which likely played a factor in the opening.

This chart is a point to point HF propagation forecast and shows how likely an opening is on each of the bands from PY2XB in Brazil to BV3UF in Taiwan. As you can see, the long path on 28 MHz is very good from 24:00 to 06:00.

By contrast, the short path prediction is very poor at this time. The DX spots just report stations heard but no-one seems to mention short path or long path.

Propagation Mode???... As mentioned already, TEP (Trans-Equatorial Propagation) is likely to have been involved but how much? Was it partially TEP with the rest of the path via F2 propagation? Was there greyline and chordal propagation involved across the Pacific where the sun was setting?

Some seem to be very quick to explain every long distance opening as being simply TEP but remember that we're talking about a path of 21,000kms at 50 MHz. I'd suggest that it's a lot more complex than that.

Just for reference purposes, the solar flux on the day was about 127.

Notes... This was a reasonably good opening between two areas with a lot of 6m activity. The maps and data I have presented above is just a sample of this opening but it does demonstrate the distances achieved.