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,
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
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:-
Long distances have been recorded on 4m this year by Es. The following is noted in Dubus
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
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.
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
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 http://iono.jpl.nasa.gov/latest_rti_global.html
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
Auroral oval - http://sec.noaa.gov/pmap/gif/pmapN.gif
Aurorawatch - http://aurorawatch.lancs.ac.uk/
Solar X ray flux - http://www.solarham.com/xray.htm
Space weather bureau - http://www.spaceweather.com
DK0WCY online magnetometer - http://www.dk0wcy.de/magneto/magnet.htm
Kiruna and Lycksele - http://www.irf.se//Observatory/?link[Magnetometers]=On-line_sp_access
GM4PMK magnetometer - http://www.marsport.org.uk/observatory/yesterday.htm
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 http://www.g0kya.blogspot.com/
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
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)
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.
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
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.
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.
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
pdf format [4.5MB]
“Measurements of Doppler shifts during recent auroral
backscatter events” - Six News 78, October 2003
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
Six Metre Group
G5KW award for 2003. Article
in pdf format [6.0MB].
“Transatlantic propagation by Sporadic E at 50MHz” - RadCom,
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.