Tuesday, 28 October 2014

European 6m Sporadic E (Es) study

CS5BLA as received at DK8NE - click for full size.
This summer I undertook a study into 6m Sporadic E (Es).

The mains reasons for this were:

1. To establish a database of Es contacts that anyone could use for research.
2. To evaluate claims that Es can be periodic – that is, good Es conditions may repeat themselves over a finite period.
3. To look more closely at so-called Short Path Summer Solstice (SSSP) propagation, when stations in Japan (JA) are regularly heard in Europe around the time of the summer solstice (June 21).

The first task was to find a way to create a database of contacts on 6m. The decision I took was to use the Reverse Beacon Network (RBN). This is a fully automated system that uses CW skimmers to look for, decode and report signals on the amateur bands.

The plan was to analyse 6m beacons received by the skimmers in Europe. This would take out any human element and also give 24-hour coverage as beacons operate continuously.

So each day from May 1 to September 30 I downloaded the daily RBN logs, and pulled them into Microsoft Excel. Once there I was able to use Excel's “Filter” command to leave just the 6m CW reports received in Europe. A final filter was applied to remove all contacts received in the same entity, for example DL to DL. This reduced the file sizes tremendously.

What were left were certainly not all Es contacts. Only by later inspection would it be possible to look for potential contacts in a typical Es range of 800–2,200 km (500 – 1375 miles).

What I ended up with were monthly Excel files, ranging from 13.9Mb in July 2014 to 1.5Mb in September. By opening them in Excel it was then possible to use the “Filter” command to look at specific paths.

Ultimately, I tried to combine all five months into a single Excel file for others to use, but with more than 162,000 entries or lines the file wouldn't save correctly.

The four paths examined - click for full size.
To look for any periodicity in Es openings four paths were selected as received by DK8NE located at JN59FW in mid Germany. This RBN skimmer was chosen as it was in use over the whole six-month test period. There were two days when it was offline due to an internet failure, but Uli was able to e-mail me the missing data.

The DK8NE 6m skimmer uses an M2 HoLoop at 45m AGL, which feeds two skimmers covering 50.000-50.190 MHz (Perseus SDR) and 50.300-50.490 MHz (SDR-IQ), both using a convertor.

I also looked at JA openings into EU on 6m.

The end result was that I ended up with a lot of data, which is being used for a feature for the RSGB's RadCom magazine.

But if you want to download the data and have a look yourself you can. Just choose one or more of the links below. Once you have the file in Excel or OpenOffice/LibreOffice Calc you can use the "Filter” command to select what you want to look at.

Downloadable Excel Files: