Eclipse Effect?
Some tests to see if any effects on the D layer might be seen during the partial eclipse of March 20 2015.
My location IO90IR 1.31 West, 50.74 North Eclipse path http://i.dailymail.co.uk/i/gif/2015/02/Solar-eclipse-2015-v.gif Note the black area, the only part where totality occurs.
See the RSGB page https://thersgb.org/publications/eclipse-experiment/150121-eclipse-2015.pdf
The RSGB suggests A Scottish station 810KHz Westerglen 3°50'W 55°58'N about 386 miles, 615Km, North. Also on this channel is Burghead, further but synchronised so this might contribute.
Northern Ireland, Ulster, LISNAGARVEY Location: W006° 04', N54° 30 around the same distance NNW of me. These stations fade out after sunrise, examples below.
I also monitored Cuba on 5025KHz and Nashville 4840KHz, recordings further down the page.
And the three UK 5MHz beacons 5.290MHz, two Iceland long wave stations 189, 207KHz... 9 stations monitored while we were shopping. It looks like 8 of them could well have been affected. (There is actually a 10th station, Morocco on 207KHz, because it was there...)
All on one computer!
But with the advent of wideband SDR this is nothing. I've just read that DK8OK recorded 2MHz of spectrum to analise after the event!
I'm not sure why I did this. Maybe to plan some QSOs for the next similar one 12 August 2026?
810 & 1341KHz
Below, the daily overview. Note that observing the two stations on a single receiver shows strengths to be similar overnight. I have not corrected the charts, we are looking for variations on each individual signal.
The two images below show that daily variations will be seen, any small early variations will not be able to be attributed to an eclipse effect but after about 08.30 signals have subsided..
On the morning of the eclipse the blue trace of possibly Westerglen rises about 25dB at 09.30, any effect on the Ulster station is not obvious.
Westerglen is co-channel with Burghead Scotland it is possible this further station was received, no way of telling..
4840 & 5040KHz
Transatlantic path, at 5MHz this is a night-time path. Two signals, one from Cuba, the other Nashville Tennessee.
The top 2 pictures show "normal" propagation on 15 March with a solar flare occurring before signals have completely faded.
The morning of the eclipse of 20 March clearly shows the partial return of night-time propagation. Around 09.10- 09.20 signals 15-20dB stronger than without the eclipse.
Below, The signal from Nashville as it fades out in the morning. Note the effect of a M1.0 solar flare at 09.40. Rapid loss of signal, slowly returning.
The signal from Cuba does not show the effect of the M1.0 flare so clearly.
5290KHz
UK 5MHz beacons. 20 March 2015
These only transmit every 15 minutes.
At 09.30 the closer ones, red GB3RAL 90kM, green GB3WES 440km drop in strength.
Blue GB3ORK at 930km rises at 09.45 as it did at sunrise, 06.15
180 & 207KHz
I'm also looking at the long wave Iceland stations on 189 and 207KHz. These vary a lot, even more around dusk and dawn. It will be difficult to determine any eclipse variations.
The image below, from Spectrum Laboratory's "Watch and Plot" shows 3 Long Wave stations. The purple is Morocco, I included this just because it might be of interest.
The grey and green traces are from Reykjavik Iceland. This path is more likely to be affected but as the signals are so variable any eclipse effect is unlikely to be identified.
The red line just visible along the bottom shows the frequency of the Iceland station on 207KHz, a crystal oven with the heater going on and off. Variation is only about 0.1Hz.
On the eclipse morning, this shows the two Iceland stations peaking at about 09.45 . My 85% 09.30, Iceland closer to 100% 09.45.
Summary.
Looking at my recorded figures, peaks in chronological order. These may not agree with the charts which sometimes do not draw precisely.
G4ZFQ Cowes IW IO90IR Friday 20 March 2015
Time of peak
09.10 Cuba 5025KHz Rise and fall of 20dB over 60 minutes
09.25 Nashville 4840KHz. Rise and fall of 15dB over 30 minutes
09.30 NVIS dropped out on GB3RAL and GB3WES 5.290KHz.
09.35 Scotland 810KHz. * Rise and fall of 25dB over 60 minutes
09.35 Iceland 189KHz. * Rise and fall of 20dB over 30 minutes
09.45 GB3ORK 5.290KHz. *
09.45 Iceland 207KHz. * Steep rise and gradual fall of 25dB over 60 minutes. But levels 10dB below the observed peak are not uncommon during the day. Both long wave signals normally vary considerably .
* I did not monitor but these stations were strong enough to be audible with good signals, although only briefly.
This page explains a little about my charts https://sites.google.com/site/g4zfqradio/greyline_charts
The computer a oldish 2 core with two Delta 44s, a Delta 1010L, X-Fi, on board sound, 10 stereo systems. Receivers include my large collection of Softrocks.