Tropo Duct 10/11 July '23 - 144 MHz WSPR

[VK2KRR]

A somewhat unexpected Tropospheric Ducting opening overnight and still ongoing now in south east Australia on 2m WSPR (and moving to SSB voice QSO in some cases) with distances extending as far as 1421 km east west from Sydney to Port Lincoln.
Pretty dicey looking on Hepburn charts but there is some weak colour around but not really so much on the longer paths.
The MSLP map shows a great large high pressure weather system with cold fronts pushed far enough away to the south.
From discussion with others it seems this duct is quite elevated and rather unusual, its rare for this event happen from Sydney to Port Lincoln. Having said that, the guys using WSPR are finding these paths available potentially more often than one would think.
Being the middle of winter we expect the tropo may last all day and wait in anticipation to see what may occur this evening after sundown.

[VK2KRR]

The Tropospheric conditions experienced on the 10th July also continued through the day and night to the 11th July.
Quite interesting conditions being experienced across the inland from the Sydney region right across to stations in VK5 including Michael VK5LN at Port Lincoln.
Later on we saw some spots from Wayne VK2XN near Narrabri to VK5PJ, VK5GF and VK5AKK max at 1216 km. Also with a late hit on the 2nd longest path was Colin VK2KCM near Grafton who received two lonely signals from Peter VK5PJ in the early morning hours at 1412 km (only 9 km less than the 2EFM to 5LN path) at 1440z and 1620z.

MSLP map (attached) looks good with a high pressure system still dominating. Hepburn chart does not look very favourable at all to be honest (attached).

Paths from the Sydney are to VK5 were quite incredible often times with substantial signal levels. One thing to note was on many occasions the path from myself VK2KRR was not as good as those stations near Sydney to VK5, at times as much as 20dB stronger, despite being further afield by 400 km or so.

Paths to Michael VK5LN were still quite numerous and substantial in strength at times, it seems the last recorded signals by VK5LN were in the very early morning hours of the 11th. Unsure if paths with resume back to Michael again or not. The weather system may progress through too much, but this could mean better chances for those in NE NSW and SE QLD.

It will be interesting to again observe the progress of this tropospheric opening over the next 24 hours.

[VK4EKA]

So are we looking for ZL this weekend? 16 17th SEPT 2023

[VK4CZ]

Certainly well be. Hepburn already delivering with forecast VK2 to ZL on Saturday immediately delivering a path. SE VK4 starts 04:00z Sunday 17/9 and will peak on Tuesday [for those not QRL]