2024 Sporadic-E poor but one highlight ZD7BG

The 2024 Sporadic-E season has not been good for me this year, a few openings as high as 70 MHz, but no Band II FMDX except for one day when I was away at work so missed it.

Best DX for me this year was at 1900 UTC on Monday 1st July 2024 on 50 MHz FT8 when I worked ZD7BG on Saint Helena island in locator square IH74DB, a distance of 7830km.

The propagation was a combination of TEP+Es, with the Es having a good open path at the time between the UK and North Africa.

SDR and other FM DX equipment in use for 87.5-108 MHz

 

SDR and other FM DX equipment in use

Yesterday, 12:21 PM

Hello all,

Thought I would share details of the different SDR and other FM DX equipment, I have setup here now, as a newcomer to FM DX.

My location is Penrith, IO84, at the very top of England close to the border with Scotland.

I have a SDRPlay RSP1A receiver, 1kHz-2000 MHz coverage, which has up to 10 MHz wide bandwidth, although I typically view 8 MHz. I find this wide bandwidth useful for viewing a good portion of the FM Broadcast Band II 87.5-108 MHz here. I can easily spot tropo stations and of course any via Sporadic-E, the only downside is this radio is susceptible to RF from my Amateur Radio operation, so I use the automute feature with SDR Console software. I also sometimes use SDR# v1913 software as it has an auto logging RDS scanner feature, so when not at home or overnight it can monitor the FM band for me. Finally the SDRPlay RSP1A has the ability to record IQ files in up to 10 MHz widths, really useful for later analysis of openings.

My second SDR is a new AirSpy HF+ Discovery, a couple of times each year AirSpy discount their products by 15-20% from their approved dealers. I managed to get mine for only £116 and it arrived here in less than one week. Coverage is 1 kHz-31 MHz and 60-260 MHz, with a maximum viewable bandwidth of 768 kHz. The disadvantage is I can only view a small part of the FM Broadcast band at a time, but the advantage is the filtering, it is not affected at all by my Amateur Radio transmissions. I use SDR Console software with this receiver and have it monitoring three FM frequencies 87.5, 87.6 and 87.7 MHz for any RDS catches via Sporadic-E.

Using data from FMlist I have been able to import every FM radio station details and RDS identifier into the SDR Console database, I have imported all of Europe and North Africa. I could import the entire World if I wish. Having this database means when an RDS code is received the software checks the database and records the details automatically for me, telling me also if that RDS is a match.

My last FM radio is a ready built self contained portable SDR called a TEF6866, which I managed to find online for only £94 and again arrived in less than one week from purchase. this radio is very sensitive, the inbuilt RDS decoder is excellent.

For aerials I am limited by not being allowed visible external ones. So I use a combination of Wellbrook 1530+ Loop outdoors, or AirSpy loops indoors and telescopic whips. Not ideal, but I have managed when not at work to catch some Sporadic-E openings this season and receive stations from both Spain and Portugal so far. My best being a station from Portugal on 92.1 MHz on 7th June 2023 at a distance of 1673 km or 1040 miles.

A friend who follows me on Twitter saw my interest in FM DX and told me on 26th May 2023, whilst driving his car near to my location in Penrith, IO84, that on 94.2 MHz he received a station from Algeria, North Africa at a distance of 2100 km or 1300 miles. I clearly need to try harder.😂

VHF Propagation identification determined by Min/Max distances (V3.0)

 

VHF Propagation identification determined by Min/Max distances (V3.0)
Distance	Less than 110km	110-400km	400-800km	800-2350km	2350-4700km	4700-8000km	Over 8000km
Propagation type	Line of Sight (LOS)	Tropo Scatter (TRS)
		Tropo Ducting (TRD)				TRD + Es
		Aurora (AU)
		Aircraft Scatter (AS)	Sporadic-Es (ES)		Sporadic-Es (ES) x2 hops	Sporadic-Es (ES)x3 hops	Sporadic-Es + TEP
			Meteor Scatter (MS)		Trans Equatorial Propagation (TEP)
						F2 Layer reflection (F2)
Required conditions or assists with ID	True Line of Sight is up to 50km, but can be extended by height i.e. elevation ASL or by refraction (LOS)	Stable High Air Pressure, as often seen with fog (TRD)	Raspy distorted tone & audio distortion (AU)	April to September with peak in June, small opening in December possible near Equinox (ES)	Sea path required for longest rare distances (TRD)		Often misidentified as ES alone on DXcluster, which is impossible. Main distance component is TEP and both stations need to be on opposite sides of Magnetic Equator
		Typically around 4 minutes duration (AS)	Mostly short duration pings of seconds or shorter, but can be minutes (MS)		Stations need to be either side of Magnetic Equator (TEP)	Favours Autumn to Spring months during Solar Cycle Peaks, approx every 11 years

Misidentified Propagation mechanisms for Region 1 VHF DX records

I found the following Region 1 DX record distances for 50 MHz Sporadic-E contacts online today

Distance record on 50 MHz Propagation : ES

Band	Propagation	Call a	Loc	Call b	Loc	Mode	Date	Distance
50 MHz	ES	EI3KD	IO51VW	VK3ZL	QF22FE	FT8	2019-07-24	17370
50 MHz	ES	YO7VS	KN14VH	VK4KK	QG62MQ	CW	2000-01-25	15153
50 MHz	ES	9M6XRO	OJ85AW	CT3HF	IM12OP	CW	2011-07-01	13458
50 MHz	ES	IK0FTA	JN61GV	VK8AW	PH57KO	CW	2013-06-24	13261
50 MHz	ES	HA0DU	KN07TM	CE2/VE7SV	FF47FA	CW	2012-05-27	12858

They cannot be correct as Sporadic-E layers/clouds occur at a height of between 90-130km above the Earth's surface (average 110km) and with VHF being line of sight and the curvature of the Earth each hop maximum distance being around 2350 km, the same as for Meteor Scatter. 

Double hop Sporadic-E clouds are well documented and can extend the maximum distance to around 4700 km, rarer Triple hop to around 7000 km, but this all requires the maximum distances for each hop and the chances of three or more Sporadic-E clouds lining up perfectly get less and less plausible.

Whilst Sporadic-E occurs in the Northern Hemisphere between April to September, with a peak in June each year and a smaller event around December, it is extremely unlikely if not impossible that solely Sporadic-E can account for the 12000-17000 km distances shown in the table above.

In the last couple of years documented extreme long distance QSO's have taken place on 50 MHz between Australia and Europe, one well known example was the station of VK8AW who worked into Europe and the correct Propagation mechanism was identified as Trans Equatorial Propagation (TEP) from his station reaching approximately North Africa (equi distant) and then stations in Europe being reachable via Sporadic-E extending that distance so that two way QSO's could be made by those fortunate enough to be in the right Es hop distance.

If we look at the table above we can see the same station VK8AW working IK0FTA in June 2013 at a distance of 13261 km, this is again highly likely to be a TEP + Es combination given the distance and the time of year. It would require 5+ absolute maximum Es hops with clouds perfectly situated to allow that, simply not likely at all.

A significant part of the problem is that formatted DXcluster spots only have limited options of Propagation mode to be entered by the operator or observers, being either Es or TEP, but not both TEP+Es.

Let us look at the other entries

EI3KD to VK3ZL at 17370 km, would require 7+ perfect longest distance Es hops, so again cannot be correct. Interestingly VK3ZL is located in South Australia near Melbourne and looking at the globe it would mean TEP from him to around Israel together with double hop Northern hemisphere Sporadic-E to make the distance shown. Entirely possible in July.

YO7VS to VK4KK at 15153 km, would require 6+ perfect longest distance Es hops and it is in January so what Propagation mechanism could it have been, if not involving Es? Probably F2, the solar cycle peaked the following year when I heard VK via F2 on 50 MHz.

9M6XRO to CT3HF at 13458 km, would require 5+ perfect longest distance Es hops, again highly unlikely. 9M6XRO was located in Eastern Malaysia just to the North of the Equator, so presumably that would discount TEP also. CT3HF in on Madeira Island in the Atlantic West of Africa. 2011 was another solar cycle maximum year so probably F2 on 50 MHz.

Finally, HA0DU to CE2/VE7SV at 12858 km, would require 5+ perfect longest distance Es hops. Located near Santiago, Chile TEP would put the signal of CE2/VE7SV reaching NW Africa, within double hop Es distance from HA0DU. TEP +Es most probable in May.

My own best distance on 50 MHz was last week on 26th April 2023 working ZS6WN a distance of 9264 km, TEP + double hop Es. 

Super start to 2023 Sporadic-E season

The 2023 Sporadic-E season started for me on Monday 24th April 2023 on 50 MHz with a good opening to Europe.

What I didn’t expect though was that only two days later on Wednesday 26th April 2023 between 1244-1249 UTC I would work on 50 MHz ZS6WN in KG46SC square, South Africa, for a new personal best distance record of 9238 km.

The propagation mode appeared to be via Sporadic-E, however this would mean at least a quadruple hop (4x2350km) for that distance, which if that was the case would be most unusual for me with triple hop being the best I had seen before. More likely it was a mixture of Sporadic-E and TEP

My 50 MHz station at present comprises of an Icom-7300 running 50 W into a quad band vertical mounted at ground level and hidden in a garden bush due to being in a Conservation area and not being allowed visible external aerials