August 2010

Propagation Summary
Conditions have remained the same during July, apart from the slight disturbance between the 23rd and the 28th (Sunspot Number 1084) during which the Boulder A index will have gone as high as 15 and the K index wil have hit 5. The Solar Flux will have dropped to 72 by 1st August, returning to it’s the recent ‘norm’ of 80 by the August 6th. ( From: http://www.wm7d.net/hamradio/solar/27d_forecast.shtml )
Sunspot numbers are still around 50% below the targets forecast by Solarcycle24.com (http://solarcycle24.com/sunspots.htm ) See also Steve Nichols’ UK Short Path Propagation Forecast at: http://www.infotechcomms.net/propcharts/

Steve Nichol (GOKYA) ‘s Propagation Forecast
“Some people have suggested that the bands are improving, but I think they are confusing Sporadic E (Es) openings with F layer. This seasonal effect is opening up 20-10m and even 6m and 2m with good, strong openings up to 1,300 miles.
Multi-hop Es is stretching this even further, but we are not seeing an improvement in F layer propagation and Es will be less prevalent as the summer wears on.
Mid-to-late September will be the acid test – and with flux levels in the 70s we are not going to see many trans-Atlantic openings on 10m. Sorry!

20m (14MHz) is likely to be the best DX band between sunrise and sunset, although the band will be noisier than the winter period and not as reliable for long-haul contacts. The higher MUFs at night mean that 20m may remain open during the evening to DX. Short skip may also be possible due to summer sporadic-E.” http://www.g0kya.blogspot.com/

All About Sporadic E
“Sporadic E is irregular scattered patches of relatively dense ionization that develop seasonally within the E region and that reflect and scatter radio frequencies up to 150 MHz. Sporadic E is a regular daytime occurrence over the equatorial regions and is common in the temperate latitudes in late spring ,early summer and, to a lesser degree, in early winter. At high, i.e., polar, latitudes, Sporadic E can accompany Auroras and associated disturbed magnetic conditions. It can sometimes support reflections for distances up to 2,400 km.
Sporadic E is a form of propagation that can arise with little warning, and enable radio frequencies of 150 MHz and more to travel over distances of a thousand kilometres and more. Many people will have experienced it in the days of the old VHF TV transmissions.
When sporadic E propagation arose, it would result in severe interference to the signals. Even now VHF FM broadcasts in the 88 - 108 MHz band can be affected. In many instances the arrival of Sporadic E can cause unwanted interference as signals that are normally too distant to be heard appear. possible.
Sporadic E arises when clouds of intense ionisation form in the region of the E layer. These clouds can have very high levels of ionisation, allowing frequencies up to about 150 MHz to be reflected on some occasions. The clouds are usually comparatively small, measuring only about 50 to 150 kilometres in diameter. Their shape is irregular. Sometimes they may be almost circular, whereas others may be long and thin. They are also surprisingly thin, often only measuring a few hundred metres in depth.
These clouds appear almost at random, although there are times when they are more likely to occur. They form in the day, and dissipate within a few hours. You can read the complete article at:
http://www.g4xgt.co.uk/what-is-sporadic-e.htm
There are also some extra Sporadic E related links and more at: www.jameswelsh.org.uk