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Recent tropospheric propagation on 23cm
I noted some very poor propagation on 23cm on 23 Oct 2022. The signal from the GB3USK beacon (31km) at 1709UTC was extremely weak (-122dBm), suggesting a fault. But by 1912UTC, the signal had improved to -91dBm, almost normal.

This may well have been caused by sub-refraction.  "In sub refraction, the rays bend less than normal. This phenomenon occurs when temperature decreases but moisture increases with height. In extreme cases, the radio signal may be refracted out into space."  See

Extreme frost on 1 Jan 2021
Temperature was -6.3C and extreme frost on 23cm antenna (Wimo 44ele). Signal from the local beacon was 20dB down until the frost melted.
Frost on yagi

Older material on 50 and 70MHz propagation:-
A brief opening at 1447z to A92IO Bahrain on 70.2MHz!  Lasted about 5 minutes, exchanged 559. Dave also worked into HA.  Currently a world record distance of 5234km on 70MHz Es (but not all propagation modes - TEP is greater), and a first G to A9 on 4m.  Thanks Dave!
Regrettably, in all the excitement I forgot to turn the recorder on until Dave was fading out. Here is Dave calling cq at very low signal level (mp3, 504kB).  And here you can see the great circle path going over HA:-
Prop map to A9

Long distances have been recorded on 4m this year by Es.  The following is noted in Dubus (3/2013, p128):-
On 12 June, CT1HZE heard A92C/B  for about 2 hours (5653km)
On 30 June, 1, 3 and 4 July, EA8/DL3GCS heard WG2XPN/B (5763km)
On 3 July, CT1HZE heard WG2XPN/B  (6081km)
On 7 July, DJ5MN heard WG2XPN/B (7093km)
On 7 July, GJ4NOK heard WG2XPN/B (6108km)
On 7 July, IZ5ILX heard WG2XPN/B (7190km)
On 7 July, IS0AWZ heard WG2XPN/B (7387km), currently a 4m receive world record.

Today there was a very intense Es opening with the whole of Europe audible on 6m and much on 4m as well. The skip on 4m was very short - I worked PA1AT (659km) and PE5T (645km) around 1325z.  Band open to SP, S5, HA, OZ, EA, EA6, EA8, I, ES.  I worked EA8ACW/P at 1541 and was spotted on cluster by LA4LN. 
SFI=90, K=1, A=6;  Auroral oval almost white, Xray flux very low.  Another example of good Es correlating with a quiet geomagnetic field.

Strong opening on 6m to South Africa reaching as far north west as IO81 (at least).  Stations in ZS and V51YJ heard.  Possibly F2, supported by absence of Es as far as I could tell - weak Eu signals were likely backscatter (and this is probably too far north for TEP alone).  Later on C5YK was a strong signal here - almost certainly F2.  On 4m, QSOs between ZS and SV were made by TEP.  A CME shock arrived about 2200z triggering Aurora.

Major opening on 6m from Europe to Caribbean, Brazil, Surinam and Argentina (and others?).  Presumably Es and TEP again.

Opening on 6m to Reunion Island and Mauritius on 6m by Es + TEP.

First link up of Es and TEP heard here on 6m this cycle. Z21SIX beacon heard at 1704z followed by Z21BB working into I, EA, ON, PA, DJ, G.
Brief recording here. (.mp3, 391kB)

First 4m Es opening this season (to OM)

Postscript to talk on Radio Aurora at Bristol RSGB group 28 November - a list of band 1 TV stations is kept by G0CHE at his website.
It appears that there are no longer any in western Europe that would be useful for auroral detection.

26/09/2011 -
Aurora and auroral E - this was a fairly intense opening with magnetometers showing large variations, and good propagation for GMs and Scandinavian stations. Worked GM8LFB at 1710, then LA8AJA and LA8AV all on 6m. GB3ANG on 4m was 52A and 529 by tropo at the same time.  At 1918 GB3CFG on 4m was 41A from 020degrees, with the Ar signal about 435Hz HF of the true frequency.   There was the usual lull around 2100z and then GB3CFG returned around 2124z.  At 2129 OY6BEC was audible on both 4 and 6 by Au-E, then GB3LER on 6 on Au-E at 2148z.  By 2200z all signals seemed to have gone.

Total electron content was unusually high. Data from


25/09/11 - F2 opening - 5N7M worked - first 6m F2 QSO for 9 years.

22/09/11 - F2 opening - D4C beacon heard here on 50.0338 (4285km) up to 599, 1926 to 2009z on 22 Sept 2011. The beacon sends the wrong locator of HM76mv - probably should be HK76mv.
21/09/11 - TEP opening - SV8CS worked ZS6WAB on 70.2 ssb on 21 Sept 2011 at 1809z.

Dr Lucie Green's lecture on the sun, solar flares and CMEs including videos

Propagation links

Auroral oval -
Aurorawatch -
Solar X ray flux -
Space weather bureau -

Magnetometers -
DK0WCY online magnetometer -
Kiruna and Lycksele -[Magnetometers]=On-line_sp_access
GM4PMK magnetometer -

Understanding LF and HF propagation

In 2008/2009 Steve Nichols G0KYA and Alan Melia G3NYK wrote a series of features on understanding LF and HF propagation for the Radio Society of Great Britain's (RSGB) "RadCom" magazine.  Steve looked at the D, E and F layers, Sporadic E, the MUF/LUF, using solar data, propagation programs, NVIS and much more.  The articles have now been released as a single pdf document and can be found at

Observations on the 2011 Es season (at 23 Sept 2011)

From this location it was not such a good year for Es, and mostly the propagation seemed to favour southern Europe, but some good contacts were made. Good openings on 4m started on 26 May (S5, YO, OM, 9A, OK).  10 June was good on 4 also (GM, EA, OY, LA, ES, OH, OM, OK).  New ones were YO2IS, TF/DL3GCS, TF/G4ODA, the latter on 8 Aug. There was a late opening on 19 and 20 Aug (YO, OZ, ES, OK).  On 3 August at 1607z, there was a brief indication on the spectrum waterfall on the frequency of the WE9XUP beacon, but no ID could be confirmed.

On 6m, nice ones worked were 9Y4D, PJ4E, A45XR, A92IO, PJ2BVU, TF/DL3GCS, VO1KVT, PJ6D, PJ2/DJ9ON, EX2A, EX9T, PJ76, ST0R.  Many signals were weak and most of these were on cw.  The highlight was another opening to the far east on 28 June around 0940 to 1122 - DU7/PA0HIP and DU1GM both heard very weakly but not worked.

Observations on the 2010 Es season (at 20 July 2010)

This season has been remarkable (again!) for the very long distances worked on 6m, the new countries and distance records broken on 4m, and the rather poor transatlantic openings from here.
The long distance 6m contacts made in 2009 were impressive - OA4TT working into Europe, many qsos at >11000km, and the record Es contact JR2HCB to HI3TEJ at 13288km.  This trend continued in 2010 with openings to Africa (TR, TN, TL, C5, J2);  Middle East (A9, A7, 9K), and especially the Far East (BA, JA, XV, JT, 9M2). There were doubtless others I haven't noted.  The transatlantic path by contrast was very poor from here - there were several openings from North America and the Caribbean to northern Europe which missed me, and of course openings to Mediterranean countries especially EA and CT. But from here it was sparse, with only one contact to Florida, one to French St Martin and one to French Guiana.  There was an opening on 6 August 2010, worked N3DB, K2SG and W4MYA all cw all about 559, and all east coast.

On 4m the Es distance record was broken when D44TD worked OZ2LD at 5167km.  New countries appeared on the band - OH, LA, T7, CU were all very welcome additions, with Italy and Spain managing to renew temporary licenses.  CT1HZE heard the US beacon WE9XFT at 6070km on two occasions - 26 June and 4 July.

For me it was pleasing to add 14 new countries on 6m and 3 new ones on 4m, but there are always missed opportunities and I either didn't hear or missed the Far East on 6m, and D4 and CU on 4m.

Sporadic E is a mode that has both deep frustrations and great opportunities - when everyone else in the country can hear the dx at S9 and I hear nothing, I start to check the antenna is still in one piece.  But when a bit later the dx comes through and I get a "personal" opening at S9, there's a great sense of "yeesss!"

This year I have been making some recordings using polarisation diversity - check the link below.

Polarisation diversity recordings on 6m

Interesting Es opening on 6m with FAI - 22 Jan 2010

Published articles and talks

Sporadic E – a presentation to Chippenham Amateur Radio Club, July 2010

 A talk about the history of Es on 4m and 6m and the mechanisms and characteristics of Es.  Presentation in pdf format [4.5MB]
Chilton ionogram showing Es

“Measurements of Doppler shifts during recent auroral backscatter events” - Six News 78, October 2003

This article describes the measurement of Doppler shifts of auroral returns at 48MHz and shows how changes to these shifts may in some cases be due to the reversal of electron flow around magnetic midnight. The article won the UK Six Metre Group G5KW award for 2003.  Article in pdf format [6.0MB].photo of G5KW shield

“Transatlantic propagation by Sporadic E at 50MHz” - RadCom, July 1986

This article analysed the incidence of transatlantic openings and showed through a statistical analysis that summer time openings to the UK were not sunspot-related, nor transequatorial, but that multi-hop Es was the most likely explanation.