3051 km opening on the 144 MHz band across Australia? - 24th Dec 2022

Very long distance propagation paths on the 144 MHz band are always of interest and those that exceed 3000kms are especially so. In Australia and New Zealand, there are quite a number of radio amateurs using the WSPR beacon mode to cary out propagation tests.

Leigh, VK2KRR reports on a special 3051 km opening on 144 MHz on the 24th of December 2022. It should be noted that countries in the southern hemisphere are now in the middle of their Summer Sporadic-E season.

Leigh writes..."This afternoon 24.12.22 at 0524z I noticed a report on WSPRview of VK2EFM to VK6CPU/p on 2m at 3051 km. Initially I thought it must be a mistakenly reported spot sent to wrong band, but upon further investigation and discussion with those involved, it appears this spot was real, which is quite unbelievable really considering the circumstances at the time.

The crazy part about it was that the propagation was well in decline from a quite good high MUF period which had lasted a  number of hours with MUF reported up to 107.7 MHz and path covering a good deal of southern Australia. 

Coincidentally at the same time there is also tropo propagation across the Great Australian Bight from VK5AKK to VK6CPU/p and VK6NI.

To make it somewhat more questionable, Allan Savins VK2EFM transmitted on both 6m and 2m WSPR at the same time at 0524z as was demonstrated by the local reports.

The propagation question would be, how did the signal get across? A double hop E, a Chordal E? or maybe a single E hop then into tropo ducting across the Bight?

Notice the path exactly lines up with the VK5AKK tropo path, which is interesting.

Also of note is that there was no reception of any 6m WSPR signal from VK2EFM in VK5 or VK6 at 0524z, the max distance was 440 km to myself which was probably some sort of backscatter.

The last 6m reception of VK2EFM in VK5 was 12 mins prior to the 2m path, and the last EFM 6m to VK6 was 14 mins prior, quite weak at -26 dB.

Another thing to note was that from midnight to 6am that 6m WSPR had good paths happening, I had a path with VK8RH all night, and was still there at 6am. So the MUF was raised through the night which is a good predictor of high MUF during the day.

Edit- oh and congratulations to Nigel VK6CPU and Allan VK2EFM for this path. VK6CPU/p is actually a remote station at Albany set up by Rob VK6LD by the way.

Leigh VK2KRR"

Analysis... Just to add to the available info, there was only one spot for the opening between VK2EFM and VK6CPU/P and this is it...

Local   (y-m-d) TX txGrid RX rxGrid MHz W SNR drift km
2022-12-24 05:24 VK2EFM QF56oq VK6CPU/P OF84xx 144.490478 10 -20 0 3051

This is the predicted tropo map from F5LEN...

It suggests that there were reasonable tropo conditions on 144 MHz across the Great Australian Bight. This would account for signals going 1800kms from the SW corner of Australia to Adelaide but what about the remaining 1200kms or so from Adelaide to Sydney?

I suspect it was probably a Sporadic-E opening from Sydney and then a tropo duct across the Bight but it's impossible to be sure.

A similar opening to this happened back on the 15th Dec 2020 as outlined in this previous post HERE

Links..

1) More examples of long distance paths on 2m can be found on my 144 MHz page

2900km+ opening on 144 MHz across the south of Australia - Dec 2021

The southern hemisphere is currently in the middle of their summer and there is plenty of activity  on the 144 MHZ band with lots of stations testing out propagation paths with the WSPR beacon mode.

In the last few days, signals in the region of  2930kms have been heard across the south of Australia on 144 MHz. 

The map above shows the stations that VK6JR has heard.

Stations heard by VK6JR (2000kms+)

 UTC (y-m-d) TX txGrid RX rxGrid                                 MHz W SNR drift     km
2021-12-25 19:28 VK2KRR QF34mr VK6JR OF76mi 144.490461 20 -17 0 2927
2021-12-29 20:34 VK7DC QE28ww VK6JR OF76mi 144.490484 10 -25 -1 2831
2021-12-29 14:38 VK3OE QF22qc VK6JR OF76mi 144.490395 20 -14 0 2765
2021-12-29 14:48 VK3DXE QF21nv VK6JR OF76mi 144.490395 20 -29 0 2743
2021-12-27 17:22 VK3ZAZ QF12ag VK6JR OF76mi 144.490448 100 -24 0 2471
2021-12-29 20:26 VK3HJV QF01tp VK6JR OF76mi 144.490408 20 -18 -4 2439
2021-12-04 22:22 VK5AKK PF94ix VK6JR OF76mi 144.490504 50 -22 0 2173

Stations hearing VK6JR (2000kms+)

UTC (y-m-d) TX txGrid RX rxGrid                                 MHz W SNR drift km
2021-12-25 19:26 VK6JR OF76mi VK2KRR QF34mr 144.490577 10 -19 1 2927
2021-12-29 21:08 VK6JR OF76mi VK7CMV QE29od 144.490482 10 -26 0 2772
2021-12-29 20:44 VK6JR OF76mi VK3DXE QF21nv 144.490422 10 -22 0 2743
2021-12-27 18:22 VK6JR OF76mi VK3ZAZ QF12ag 144.490491 10 -29 0 2471
2021-12-29 18:22 VK6JR OF76mi VK3HJV QF01tp 144.490595 10 -27 1 2439
2021-12-23 22:38 VK6JR OF76mi VK5AKK PF94ix 144.490486 10 -28 3 2173

Propagation Mode: It's likely that marine ducting across the Great Australian Bight played a large part in these openings which were just under 3000kms. Considering it's in the middle of the southern hemisphere Sporadic-E season, that mode could have played a partial role as well for some signals.

Links...

1) For more examples of long distance paths, see my 144 MHz page.

2700km opening on 144 MHz in Australia - 20th Dec 2021

Monday 20th December 2021: The Great Australian Bight is the area of water just off the south coast of Australia and is well known for producing some fine tropospheric ducts. 

On what was the 21st of December in Australia, 144 MHz WSPR signals were exchanged by VK6NI and VK2KRR on a path that was just under 2700kms.

UTC (y-m-d)         TX         txGrid RX rxGrid         MHz         W SNR drift km
2021-12-20 21:02 VK2KRR QF34mr VK6NI OF85pa 144.490562 20 -18 0 2696
2021-12-20 21:26 VK2KRR QF34mr VK6NI OF85pa 144.490553 20 -22 0 2696
2021-12-20 21:42 VK2KRR QF34mr VK6NI OF85pa 144.490552 20 -25 0 2696
2021-12-20 21:48 VK2KRR QF34mr VK6NI OF85pa 144.490553 20 -19 0 2696
2021-12-20 20:58 VK6NI OF85pa VK2KRR QF34mr 144.490427 10 -18 0 2696
2021-12-20 21:18 VK6NI OF85pa VK2KRR QF34mr 144.490427 10 -20 0 2696
2021-12-20 21:38 VK6NI OF85pa VK2KRR QF34mr 144.490427 10 -7 0 2696
2021-12-20 22:22 VK6NI OF85pa VK2KRR QF34mr 144.490427 10 -24 0 2696

The tropo opening seems to have lasted about an hour.

There was also a 2000km tropo opening on 144 MHz between Australia and New Zealand on the same day.

4000km+ opening on Band 2 from Indonesia to SE Australia - 7th Jan 2021

 

Very long distance openings on the VHF bands are always of interest and one such instance happened back on the 7th of January 2021 when Leigh, VK2KRR in New South Wales in Australia managed to log and record several FM Band 2 radio stations from Indonesia.

Normally with Sporadic-E propagation, the maximum distance is around 2300 kms. In this case, VK2KRR heard FM radio stations on the 88 to 108 MHz band from Indonesia, a distance of about 4000 to 5000 kms!

While a number of Indonesian stations were recorded, it looks as if it was difficult to get a positive ID on the exact location for each one. There was however a positive ID of RADIO FBI on the island of Bali on 91.8 MHz and at a distance of  4380 kms.

It's likely that the propagation mode was double hop or chordal hop Sporadic-E. While this is pretty common on lower frequencies like 50 MHz, it is much rarer at the Band 2 frequencies of 88 to 108 MHz.

A full list of videos from the opening on the 7th of January can be viewed HERE.

Australian 70cms digital record extended to 2,806 kms

Early on the morning of the 5th of December 2019, there was a remarkable tropo contact between Leigh, VK2KRR and Peter, VK6KXW on 70cms across the Australian continent. The distance was 2,806 kms and crossed over the Great Australian Bight, a part of the ocean well noted for tropospheric ducting.

This was a new Australian record for a digital contact on 432 MHz as both stations were using the FT8 mode. The previous record was 2,793 kms which was set back in December of 2016.

VK6KXW was running 75 watts from an IC9700 into a single yagi. VK2KRR was also running 75 watts from an IC9700 but his antenna was a box of four yagis.

VK2KRR's box of four yagis used for the contact. Source: VK2KRR on Facebook

The time of the contact was probably also a factor as tropo ducting is often at its best very early in the morning when the atmosphere has settled down and the sun hasn't risen yet.

The current non-digital record for the 70cms band in Australia is just a bit further at 2,862 kms. This was set between VK6KXW and VK7AC on the 17th of January 2019.

While examining both of these contacts, it can be difficult to relate to the distance of 2,806 kms and just how far it is. It might be useful for stations in Europe to remember that the distance from the west coast of Ireland to Newfoundland in Canada is 3,000kms, just an extra 200 kms.

Leigh VK2KRR has a nice website with plenty of VHF info, visit https://www.vk2krr.com/

Australia on 28 MHz this morning...

This one was a bit of a suprise! I had WSPR running on 28 MHz this morning and I was hearing some signals via Sporadic-E from Germany and Denmark.

Then I heard VK2KRR 3 times...all in the space of about 10 minutes. A quick check shows the distance to be 17,333 kms. If I worked it out correctly, then I think local sunset there was at roughly 06:58 UTC? So, the signals I heard from VK2KRR were about 10-20 minutes after his sunset.

It's likely that the F2 layer to the NW of VK2KRR became tilted after his sunset and turned his 'high' angle signal into a very low angle one.....hence the enhancement. After that it may have gone through several hops or become a chordal hop signal. I have often seen this before but it's interesting to see it displayed so well on screen.

These are the European stations that heard VK2KRR. The last leg of the journey to me was probably via Sporadic-E from central Europe. Notice that I was hearing a station in Denmark earlier and OZ7IT was hearing VK2KRR.

His signal seemed to have hopped over all the stations listening in the UK.