**Status update 10/12/2020: Maps are updating normally. Some page elements may not display properly in Chrome, so please try using Firefox instead**

This site has SSL security, but your browser may report that it is unsafe. This is due to the numerous 3rd party images on the site, some of which originate from websites without any SSL security. Please be assured that this website is safe, and 3rd party data has been checked to be safe.

Caching of images is an ongoing issue. On mobiles or desktops, opening the site in an incognito browser will stop any annoying caching you may still be getting.

Further updates are in my blog pages (scroll down the left info bar to find them).

Samsung Galaxy S8 Mock-up

The page links are on the left-hand sidebar if you’re using a large screen, or touch the menu tab at the top right on mobiles. Tapping the cog on the left opens the information sidebar which contains live propagation warnings and a couple of items from my Twitter feed. On larger screens the sidebar is always visible.

The map size on the propagation map pages have been reduced slightly, but clicking on the map will open it in a new tab for a detailed view in full size.

Various other tweaks have also been made to the information pages. Note the addition of a new HF propagation map for N America, and rolling archive maps for the past 24 hours. A new meteor scatter map has also now been added.

The Sporadic-E Phenomenon

Sporadic-E, or simply “Es”, is mostly a summertime phenomenon, peaking between May and September in the northern hemisphere, and October and March in the southern hemisphere.

The causes of Es are not well understood and there and many theories, although it’s known that high levels of ionisation in the E-layer (80-120km altitude) cause radio waves to refract over long distances. A single hop can be somewhere between 400 and 2400km. Multiple hops are possible and in combination with F2 propagation, global communication on the 50 MHz band is know to occur. The Es “clouds” are sporadic in nature and can happen anywhere and at any time, although they are most common in the local summer with a late morning peak and a late afternoon peak. Extreme events can last several days and span the globe, or be localised to continents. Small isolated Es clouds can add to the magic, providing surprise contacts between specific locations.

As always, if you have any problems using the site or have any suggestions for things you would like to see, please get in touch.

Andy Smith, G7IZU
Devon, UK, Europe, Earth…

Keep up to date via Twitter: twitter.com/g7izu

Note: Site-wide comments are disabled due to misuse. I can be contacted via Twitter @g7izu.