| Monday, June 23, 2008
| Solar Activity Creates DX Opportunities
|click on log to enlarge......... (blue spots highlight propagation peaks on 20m)
The last week has kept me active a lot on some of the HF bands due to some great openings into South America as well as VK.
I have noticed some interesting findings regarding the use of my Vertical Antennas and the home made full wave 20m Delta Loop, at different times during the day due to the ionospheres variable F layer.
Up until this weekend the WX has been good with sunshine and pleasant conditions. The bands have definitely begun to improve especially at my QTH on most Evenings. During daytime conditions I have experimented around on 20m with a Mono Band ½ wave vertical and the Infamous Loop.
With the second F layer seemingly being present at this time I have found the Vertical to perform noticeably better than the loop on 20m into Europe and the Middle East.
But from 1800 UTC there is a sudden change of received angle of radiated signal and the Delta Loop is phenomenal and provides outstanding performance on RX and TX with no comparison from the Hustler 6btv or mono banded vertical antenna from all directions.
This must be when the second F layer becomes unstable and allows signals to penetrate through, reaching the outer F layer with a different angle of radiation (Take off angle of signal from my antenna) which is more favourable to the Delta Loop as it seems?????.
Here is some more about those elusive layers of the Ionosphere that we love to bounce our signals off of.
The Ionosphere reflective layers
Solar radiation, acting on the different compositions of the atmosphere with height, generates layers of ionization.
Known more commonly as:
The D layer is the innermost layer, 50 km to 90 km above the surface of the Earth.
The E layer is the middle layer, 90 km to 120 km above the surface of the Earth.
Sporadic E propagation is characterized by small clouds of intense ionization, which can support radio wave reflections from 25 – 225 MHz.
Sporadic-E events may last for just a few minutes to several hours and make us radio amateurs very excited, as propagation paths which are generally unreachable, can open up. There are multiple causes of sporadic-E that are still being pursued by researchers. This propagation occurs most frequently during the summer months with major occurrences during the summer, and minor occurrences during the winter. During the summer, this mode is popular due to its high signal levels. The skip distances are generally around 1000km (620 miles). VHF TV and FM broadcast DX'ers also get excited as their signals can be bounced back to earth by Es. Distances for short hop events can be as close as 500 miles or up to 1,400 (or more) for a long, single hop. Double-hop reception over 2,000 miles is possible, too. Hopefully things will continue to improve and bands such as 12M, 10M, 6M, & 2M increase in activity with regular openings.
The F layer, is 120 km to 400 km above the surface of the Earth. It is the top most layer of the ionosphere.
The F region is the most important part of the ionosphere in terms of HF communications.
The F layer combines into one layer at night, and in the presence of sunlight (during daytime), it divides into two layers, the F1 and F2. The F layers are responsible for most skywave propagation of radio waves, and are thickest and most reflective of radio on the side of the Earth facing the sun.
I usually listen to the RSGB news on Sunday mornings 9.30 local time on 145.525 fm operating as GB2RS.
The local broadcast covers information related to the Ham Radio hobby from solar forecasts, Dxpeditions, to local Events organized by Clubs etc.
You can also catch other GB2RS News readers at various times on different bands during sunday, or via the HamInfoBar i player. If you like reading only, check out the RSGB site via the link on the right side of this page.
I often find the solar forecast quite reliable as the recent sun spot activity reported was coincidental to the contact made into VK earlier last week.
It is always amazing as well as exciting to be able to put a reasonably low powered signal into Countries at the opposite side of the world.
Using simple home made delta loop antennas and the good old F layer with some freshly charged particles to Ionize and reflect!
|posted by Simon Davison @ 9:41 pm
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73 IZ8FTW, Thank you for your Comment and also the information regarding Planet Ham. I shall take a look and possibly add my blog.
Thankyou, Chow, Gratsy
de 2e0hts Simon