28MHz band stays open all day - Thurs 13th May 2021

After the aurora and disturbed conditions on Wednesday the 12th of May, the 28 MHz band opened on that evening at about 18:00 UTC. What was really unusual was that the band stayed open that night and all through Thursday the 13th of May... roughly 36 hours. This is in marked contrast to the Sporadic-E openings for the previous few weeks where the band might open at some stage during the day and then close late in the evening.

As the 28 MHz band was open all day, I left the radio monitoring the WSPR frequency for the 24 hours. I heard a total of 945 WSPR transmissions from 87 stations around Europe which is very encouraging as it looked a few week back that there was very little WSPR activity.

The map above shows what I heard. What makes it different from FT8 is that there is a wide distribution of FT8 stations spread across Europe that are trying to make contacts. WSPR however is concentrated in pockets of activity based around mainly the west of Germany, the Netherlands and the south of England.

What I found of interest was the short skip opening to the UK...

Distances of about 1000 to 2200 kms are pretty common on 28 MHz during Sporadic-E openings but the opening needs to be really intense for the skip distance to drop down to 500kms or less.

UTC (y-m-d) TX txGrid RX rxGrid MHz W SNR drift km
2021-05-13 04:58 EI2SBC IO63dj EI7GL IO51tu 28.126074 5 -27 -3 177
2021-05-13 09:38 MW0GRJ IO83kf EI7GL IO51tu 28.126038 5 -27 4 386
2021-05-13 10:10 G4SRD IO81wi EI7GL IO51tu 28.126088 10 -17 -1 435
2021-05-13 09:38 G4SDL IO83tk EI7GL IO51tu 28.126101 1 -21 1 441
2021-05-13 07:14 G4HZW IO83uh EI7GL IO51tu 28.12613 5 -20 1 442
2021-05-13 10:04 G7GXK IO90is EI7GL IO51tu 28.126099 0.2 -27 0 507
2021-05-13 10:38 2M0WHX IO75wv EI7GL IO51tu 28.126035 5 -16 0 529
2021-05-13 06:20 M0SDM IO92pv EI7GL IO51tu 28.126006 2 -26 1 533
2021-05-13 06:36 G8IOA IO92rp EI7GL IO51tu 28.126092 5 -16 -1 540
2021-05-13 06:30 M0NMA IO92sp EI7GL IO51tu 28.126077 5 -11 -1 546
2021-05-13 06:08 M0GBZ IO91vv EI7GL IO51tu 28.126143 0.5 -19 0 560
2021-05-13 09:44 G6JVT IO90st EI7GL IO51tu 28.126111 0.2 -26 -1 562
2021-05-13 10:16 G4NXH IO94hu EI7GL IO51tu 28.126101 0.1 -26 0 572
2021-05-13 06:40 G4KPX JO02dj EI7GL IO51tu 28.12607 0.005 -23 0 594
2021-05-13 06:18 M0XDC JO01dq EI7GL IO51tu 28.12607 5 -22 0 596

2021-05-13 12:28 G4EDR IO94uf EI7GL IO51tu 28.126091 5 1 2 601
2021-05-13 10:08 G3JKF JO00bs EI7GL IO51tu 28.126125 5 -27 0 603
2021-05-13 10:42 G3DVF IO95 EI7GL IO51tu 28.126179 0.2 -26 0 629
2021-05-13 08:10 G4NJJ JO02 EI7GL IO51tu 28.126076 0.2 -21 -3 640
2021-05-13 05:58 G0MBA JO01 EI7GL IO51tu 28.126046 0.2 7 0 645
2021-05-13 05:58 G0PKT JO01mt EI7GL IO51tu 28.126056 0.2 0 0 647
2021-05-13 06:38 G0FTD JO01mi EI7GL IO51tu 28.126112 0.2 -24 0 652
2021-05-13 09:34 GM1OXB IO87lp EI7GL IO51tu 28.126049 2 -6 0 729

The most unusual signal was that of EI2SBC (Shannon Basin Radio Club) which was 177kms to the north of me. I heard two WSPR transmissions...

UTC (y-m-d) TX txGrid RX rxGrid MHz W SNR drift km
2021-05-13 04:58 EI2SBC IO63dj EI7GL IO51tu 28.126074 5 -27 -3 177
2021-05-13 14:58 EI2SBC IO63dj EI7GL IO51tu 28.126078 5 -26 -3 177

Propagation mode? At 177kms, tropo is a possibility even on 28 MHz but I don't think it was. I suspect is was either very short Sporadic-E or Sporadic-E back-scatter. They were running 5 watts which is reasonably high power level for WSPR so it's difficult to be sure.

QRSS: One of the advantages of listening to WSPR is that I can see any QRSS (very slow morse) signals as well as those signals are just below the WSPR ones.

The image above shows a screen grab I took early on Thursday morning. Most of those stations in the Uk were east of London and about 650kms from me.

As an example, the signal say from G0FTD in this image is probably weaker than -20dB and in reality is buried in the noise.