Site status: ** The radio propagation maps are updating normally. Please email andy[at]tvcomm.co.uk if you spot a problem**
Current live conditions (radio conditions courtesy of The DX Robot): VHF AURORA 144MHz Es EU 70 MHz Es EU 50 MHz Es EU 144MHz Es NA Solar X-Rays Geomag Field
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Quick links (the main menu is at the top right of every page, or click the links or map thumbnails below)
Aurora map | Live solar data | SWPC Aurora forecast | The Sun Now | Global HF Radio Propagation Map | *NEW* European Tropo Propagation
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 1800km. 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.
On the left are 3 x 24 hour composites of reported contacts on the 28, 50, 70 and 144 MHz bands on 3rd June 2018 when a very strong event encompassed most of the northern hemisphere.
Solar Flux vs Cosmic Rays
We’re keeping an eye on the rate of cosmic ray detection as we approach solar minimum. As the solar flux falls, the strength of the protective bubble of solar wind in our solar system declines. This allows for more cosmic rays to impact Earth. With a weaker solar wind, the strength of our magnetic field also decreases, which exposes us more to the effects of solar flares. As the cosmic rays (atomic protons and neutrons travelling at relativistic speeds) interact with our atmosphere, they cause a cascading “shower” of particles to fall to earth, and it’s these events that are detected. In extreme cases, these events can reach the ground and are detected as “Ground Level Events”. They can cause increased rates of various cancers in humans. People travelling in high altitude aircraft, especially on polar routes, and pregnant women in particular, are at an even higher risk. When the solar wind declines, our Earth also becomes more exposed to solar CMEs and Gamma Ray Bursts from cosmic events.
Detectors around the world have been monitoring cosmic rays for many decades, and the cosmic ray rate (as of May 2018) is the second highest rate ever recorded. If the current solar minimum deepens further, it’s likely that the previously recorded high (in 2010) will be exceeded.
This site has live links to neutron monitors in Finland. Below is a composite comparison chart showing the solar flux versus neutron monitor rates from 2000 until May 2018.
About this site
My blog posts can be found integrated on the left hand side of the page, and content links can be accessed from the drop-down lists above. Blog posts are auto-forwarded to my Twitter feed which is also available on the left side. The site is mobile-friendly and running on WordPress as pure CSS, so it should run quite fast.
The site is run by myself, Andy Smith (amateur call-sign G7IZU), from my home in west Devon, England. The original web site was created in 2005 in order for me to remotely view signals reflected from meteor trails and to see auroral radio signals by using radio receivers using software displaying “waterfall” FFT plots. The primary transmitters used as the signal sources were the powerful VHF Band 1 analogue television transmitters based around Europe and further afield. Only the carrier-wave of the video signal was used as it was a powerful, stable signal. Following an extended switch-over to digital TV signals only on UHF channels, the last of those AM VHF transmitters closed down in 2012, and since then I’ve been unable to utilize any other transmitter to the same extent. I briefly experimented with the signal from the Graves satellite radar site in eastern France (see image above), but this proved unreliable as nearby hills are blocking too much of the reflection volume.
Between 2005 and 2011 I contributed automated meteor count data to RMOB (Radio Meteor Observing Bulletin) and spawned interest amongst a growing community of radio meteor observers around the world using Spectrum Lab as a tool for meteor observing. I also helped in the development of the Spectrum Lab software package by Wolf Büscher (DL4YHF) by requesting features useful to the radio meteor observing community. Above is a summary of my observations over that period. You can find some more pages from my old site in the archived pages section of this site.
THE CURRENT PURPOSE OF THIS SITE
The main purpose for this site is now for providing live radio propagation maps. The maps are created automatically by Dave Edwards’ LiveMUF application which receives global amateur radio contact data via the radio and internet-based DX Cluster network. Contact plots are created in realtime with a short delay of a couple of minutes before they appear on the maps. The maps display data from the preceeding 30 minutes, with contacts older than 30 minutes being automatically removed.
Links to the maps are provided below. They also appear at the top of the page on the drop-down menu for Propagation Maps. The maps refresh automatically every minute, so there’s no need to refresh the pages. If you find the map is too large for your screen, try scrolling down a few lines, or try pressing and holding the keyboard CTL key and press the minus key to change the screen magnification. Use the CTL and the plus key to enlarge it again.
Follow me on Twitter @g7izu
Email: g7izu(at)television.f9.co.uk (manually type the address replacing (at) with @).