F2 Skip Zone on 28 MHz - 7th Dec 2023

As the WSPRnet website was down for most of today, I left the radio on the FT8 frequency of 28.074 MHz instead. As expected, there were a lot more signals on this mode.

One thing that stood out after a few hours was the skip-zone as shown in the map above. There was no sign of any real Sporadic-E and nearly all of the signals that I heard were coming off the F2 layer of the ionosphere.

The closest signals to the south-east were front central Italy around the 1700km mark. At this distance, the signals were probably coming in to my location about 25-degrees above the horizon. Anything closer than this resulted in a higher angle and propagation wasn't possible.

To the north-east, the closest stations were about 2300kms in the north of Sweden with no sign of anyone closer.

It's also interesting to note that all of Spain is missing, even the far south of the Iberian peninsula is too close for 28 MHz propagation today.

Skip Zones on 28 MHz - 26th Oct 2021

Tuesday 26th October 2021: As the solar flux jumped up to 109, it was another good day on the 28 MHz band with 538 stations heard on FT8 in 49 DXCC countries.

The band looked pretty similar to previous day  although what stood out for me was the opening to China and Australia. These are some of the more interesting signals heard on the day...

 Txmtr Band Mode Distance Time (UTC)
VK2MBK 10m FT8 17325 km 08:22:59 (Australia)
VK2IS 10m FT8 17275 km 08:05:29 (Australia)
VK6APK 10m FT8 15125 km 09:30:14 (Australia)
9W6EZ 10m FT8 11726 km 08:57:14 (East Malaysia)
3B9FR 10m FT8 10540 km 15:51:44 (Rodriguez Is)
BX5AA 10m FT8 10221 km 08:25:14 (Taiwan)
VR2XYL 10m FT8 10046 km 08:50:29 (Hong Kong)
BD7JQD 10m FT8 10037 km 08:46:29 (China)
BG7PHA 10m FT8 10037 km 08:30:59 (China)
BD7MJO 10m FT8 10003 km 08:28:44 (China)
BA7IO 10m FT8 10003 km 08:43:14 (China)
BG0COH 10m FT8 9888 km 08:34:44 (China)
BG7SAY 10m FT8 9784 km 08:14:29 (China)
7P8RU 10m FT8 9715 km 16:22:44 (Lesotho)
BA7BK 10m FT8 9438 km 08:26:44 (China)

Skip Zone: I'm sure a lot of radio amateurs monitoring the band have no idea what type of propagation is responsible for what they are hearing and some won't care. However some of the newer operators on the band may be curious.

In this post, I'm not going to get into what Sporadic-E and F2 layer propagation is as this is explained on many other websites. 

I will however have a quick look at what the actual difference means on the 28 MHz band by looking at the map below from the 26th of October 2021.

Sporadic-E signals come off a layer in the atmosphere that is about 110kms up and the maximum range for signals is in the region of 2200kms. This is shown by the YELLOW line above. Even though the main Sporadic-E season is in the Summer months, we can still have plenty of Sporadic-E in October which is strong enough to support 28 MHz signals.

F2 layer signals come off a layer that is about 400kms up and as a result, the signals have a much greater range. F2 layer signals on 28 MHz are due to radiation from the sun and are getting better as we start heading back up towards the sunspot maximum in a few years. The GREEN line shows the minimum distance for F2 layer signals which for me is about the 2800km mark. Anything shorter and the angle is too high. Anything longer and it's probably ok out to a maximum one-hop range of 4000kms. 

The map shows the skip zone for me on 28 MHz on the 26th of October 2021. If you are on 28 MHz then you will probably have a similar skip zone. 

Just check the PSK Reporter website and see what you have heard in the last 24 hours. See if there is a gap out around 2200-2800kms.