Trans-Atlantic opening on the FM band (87-102 MHz) - 27th May 2024

On the 27th of May 2024, a little bit of radio history was made with the very first reception of a trans-Atlantic FM radio station in mainland Europe. The map above shows the radio stations that FMDXer Mauricio Molano  in Cáceres in the west of Spain managed  to log including CHCM-FM in Marystown, Newfoundland on 88.3 MHz.

Log...

UTC QRG ITU Station, location Details, remarks Distance km kW ERP

12:06 90.20 AZR R80 Rádio, Pico da Barrosa (smg) 1674kms 0.5kw

12:15 87.70 AZR RTP Antena 3, Pico da Barrosa (RDP) (smg) 1674kms  40kw

12:50 88.30 AZR Rádio Clube de Lajes do Pico, Pico do Geraldo 1896kms 0.05kw

14:25 88.30 CAN CHCM-FM, Marystown (NL) Openline with Paddy Daly. Special log: double hop. First Canadian station received from Spain! 3985kms  27kw

As can be seen from the log, CHCM-FM was heard at 14:25 UTC and it's likely that the propagation mode was double hop Sporadic-E.

Mauricio writes... "I have managed to fulfil another of my DX challenges!: to catch an FM station from the other side of the pond!. It was this afternoon, during the opening of Es, which had started around 1200Z and brought me several stations from the Azores Islands with good signals. A couple of hours later, our colleague Larry Horlick (Coley's Point, NL) began picking up Spanish and Portuguese stations. 

In the first minutes of the opening was when I caught the CHCM-FM (Marystown) signal on 88.3 with 

VOCM programming. On 88.5 I have another signal but very weak. I assume it is CBN-1-FM CBC-R1 

Saint John's, but it will be difficult for me to identify it 100%. Both frequencies are very difficult in my 

listening place (Aldea del Cano, Cáceres) due to the presence of semi-local stations on 88.2, 88.4 

and 88.6 MHz. This year the DX season has started late here, but it has started very, very well!."

Mauricio also notes that he has two receiver/antenna systems. The first one is a three element Yagi points to the Canary Islands (south-west) attached to a RSPDuo receiver. The second one is a 4-element Yagi pointing to Newfoundland and attached to a Perseus with the FM+ converter.

In this case,  the station from Canada was actually heard on the antenna pointing to the Canary Islands!

Just to clarify, this isn't the first trans-Atlantic FM stations have been heard in Europe but all of the previous reception reports were to the UK and Ireland. This is the first time of a trans-Atlantic reception report on the Iberian Peninsula and mainland Europe. 

Larry Horlick, VO1FOG in Newfoundland... Larry is a long time FMDXer and he caught an impressive haul of FM radio stations from Portugal and Spain in the same opening. Larry has the advantage of a quieter FM band on his side of the Atlantic.

One of the major advantages of modern SDR receivers is that an opening can now be recorded and then be later reviewed afterwards to see what was heard. 

Larry's log is shown below and it's worth remembering that these are FM radio stations from the other side of the North Atlantic.

The frequencies range from 87.6 MHz to 102.4 MHz and the distances range from 3632 kms to 4136 kms.

Larry says his catch of the day was SER, Estepa, Spain on 98.3 MHz which has an ERP of just 250-watts.

In conclusion... While there have been trans-Atlantic openings on the FM band before, it is still a remarkable occurrence and worth noting. Every year, we see multi-hop Sporadic-E across the North Atlantic on the 28 MHz and 50 MHz bands and while it's of interest to those involved, it's really nothing out of the ordinary.

Band 2 signals (88-108 MHz) are different though and it's always interesting to see FM radio stations from either side of the North Atlantic reach the other side. The question always remains as to how high does an opening reach? Can it get up into the aircraft band at 118 to 135 MHz? What about 144 MHz? Spain to Newfoundland on the 2m band? Is it possible? Is anyone trying?

Links...

1) See my 88-108 MHz my 88-108 MHz page for more examples of trans-Atlantic openings

2) Mauricio has his own SWL website here... https://moladx.blogspot.com/

3) FMList website... https://www.fmlist.org/

FM radio station on 91 MHz in Greenland is heard in Ireland - 19th May 2024

On the 19th of May 2024, FMDXer Paul Logan in the north-west of Ireland reported reception of a radio station in Greenland on 91.0 MHz.

Logbook 2024-05-19 
UTC QRG ITU Station, location Details Distance km kW ERP Pol
2044 91.00 GRL Kalaallit Nunaata Radioa, Niaqernaartik/KTYC (Kap Tycho Brahe) 2095 0.1 v

The radio is located on the east coast of Greenland, has an effective radiated power of just 100-watts and runs vertical polarisation. Paul logged it at 20:44 UTC.

A 52-second audio file from the reception can be heard HERE

The distance to Paul's location in Lisnaskea, Co Fermanagh is 2095kms and the propagation mode was Sporadic-E (Sp-E). While the distance is well within the maximum for a single hop of Sporadic-E, it's always interesting when a FM station in Greenland is heard in Europe.

Greenland is technically part of North America and hints hopefully at maybe some very rare trans-Atlantic signals on the FM band in the weeks ahead.

Link...

1) More examples of long distance paths on my 88-108 MHz page.

FM radio station WMIA in Miami on 93.9 MHz is heard in Chile - 23rd Feb 2023

This reception report is from the 23rd of February 2023 when Pipe, CE3SX / CE3SAD in Santiago, Chile managed to receive the FM radio station WMIA in Miami, Florida on 93.9 MHz. 

The reception took place at 21:41 local time in Chile (22nd Feb) which is 00:41 UTC (23rd Feb). This is at the right time for an evening time Trans-Equatorial Propagation (TEP) opening.

What makes this highly unusual is the distance. It might be normal during an evening TEP opening for  FM radio stations in the north of Columbia to be heard in Chile but this time, the FM radio station was in Florida which is about 2000kms further north. 

In a previous post, I reported on how CE3SX had managed to hear FM radio stations in Jamaica in February of 2022. Florida is an extra 1000kms.

Florida is usually considered to be too far north for TEP propagation so how was the range extended to just under 6,700kms?

The first option that springs to mind was that it was an evening type TEP opening coupling into a tropo duct to the north to extend the opening to Florida. The tropo map above from F5LEN shows some tropo in the area but with the island of Cuba in the way, it's not exactly conclusive.

Is the most southern tip of Florida just close enough for TEP?

Have there been reception reports like this in the past?

And if it's possible on 93.9 MHz, what about 144 MHz from Florida to Chile? Is anyone trying?

Lots of questions...

Link... For more long distance reception reports on the FM band, see my 88-108 MHz page.

Brazilian FM radio station on 77.9 MHz is heard in Portugal - 7th March 2023

This is a pretty amazing reception report. On the 7th of March 2023, SWL Hugh Cocks near the city of Faro on the south coast of Portugal managed to receive the FM radio station Radio Justica from Sao Paulo in Brazil on 77.9 MHz!

Just to explain the unusual frequency, Brazilian authorities are currently migrating radio stations from the Medium Wave band (AM) to a new eFM or extended FM band which goes from 76.1 to 87.3 MHz. This is just below the usual 87.5 to 108.0 MHz FM band i.e. Band 2.

The FM station on 77.9 MHz is actually Radio Cultura which is obliged to carry some of the Radio Justica programmes and it runs 5KW from the city of Sao Paulo.

You can listen to the reception report below and Hugh reports that it's about Brazilian employment law.

Hugh reports using a 3-element antenna with a low noise narrowband FET amplifier. The signal was at its strongest between 22:20 and 22:40 UTC.

Hugh writes... "The evening TEP starts around 2145gmt with Ch A2-A4 TV, fluttery signals as usual. Then if good 2210 or so tiny carriers from Ch5 TV 77.25MHz and then it may appear, often lower quality than this. Last night conditions were less but there was a new station on 76.9MHz playing non stop music, very weak."

Analysis... As the map shows above, the FM signal on 77.9 MHz from Brazil traveled about 7880 kms to reach the south coast of Portugal. While a signal at around 78 MHz is likely to propagate better than the usual 88-108 MHz Band 2 signals, it's still a remarkable distance.

As Hugh indicates, it looks as if the mode of propagation was TEP - Trans-Equatorial Propagation. The time of about 22:30 UTC is about right for evening TEP.

What seems unusual though is that the signal path doesn't seem to cross the Geomagnetic Equator at a right angle. Normally, FM radio stations from this part of Brazil might be heard in the Caribbean as the signals cross the Geomagnetic Equator at close to 90 degrees.

The lower the frequency then the higher the signal can deviate a lot from that required right angle. This often happens at say 28 Mhz or 50 MHz. Still though, it does seem to be quite far off 90 degrees for a signal around 78 MHz.

I'm also quite sure that the radio engineers in Brazil didn't expect the signal from their FM transmitter to reach the shores of Europe!

Further experiments... As this band is largely unused, it should be largely uncongested and quiet in other parts of the world. If these eFM radio stations in Brazil can reach Europe, can they be heard in the USA? Most of the south-eastern states in the US are closer to Sao Paulo than Portugal. Is anyone going to try?

Could it be heard further north in Europe? Say in late April or early May when the Sporadic-E and TEP seasons overlap? It only requires one Sporadic-E hop to reach the UK or Ireland but 22:30 UTC isn't the best time of day for Sp-E. Can it be done?

Link... For other long distance FM reception reports, see my 88-108 MHz page.

FM radio stations from Jamaica heard on 89 MHz & 96 MHz in Chile via TEP

Pipe, CE3SX / CE3SAD in Chile writes to say that he managed to hear two FM radio stations on 89.9 MHz and 96.1 MHz from Jamaica during a TEP opening recently.

CE3SX writes... "Stylz FM 96.1 from Port Antonio and KLAS 89.9 from Kingston, Jamaica heard in Chicureo, Santiago, Chile FF46pr Via Trans-Equatorial Propagation

Date: January 31 and February 01, 2022. Hours: 21.46CEv 00.46 UTC and 22.03CEv 01.03 UTC

Maximum distance: 5,755 km"

As Pipe outlines, the distance is around 5,700kms and is approaching the maximum distance usually associated with Trans-Equatorial Propagation. 

A video clip of the reception is shown below...

Pipe also notes that regular reception TEP signals on the 88-108 MHz band from Columbia and he is using a 7-element Band 2 Yagi as designed by YU7EF.

CE3SX also notes that there are no 144 MHz stations in Columbia (HK) and Jamaica (6Y) to try on the 2m band.

As I outlined in a recent post, there are parallel paths from Brazil and Argentina to the Caribbean on 144 MHz during TEP openings and it's likely that similar paths are there further east from Chile to Columbia, Jamaica and Cuba on 2m.

Links...
1) For more examples of long distance reception reports on 88-108 MHz band, see my Band 2 page.

FM radio station in Colombia on 93.1 MHz heard in Chile via TEP opening - 21st Nov 2021

21st November 2021: Back in October, I had intended to publish a post about reception of a FM radio station on 93.1 MHz in Columbia by Alejandro, CE3VRT in Santiago, Chile. The distance was 5000kms and the propagation mode was TEP - Trans-Equatorial Propagation.

I was so busy, I forgot to publish it and it remained as a draft! The post is now shown below for the 20th of October 2021. 

What reminded me of this was that CE3VRT heard the same radio station again on 93.1 MHz but this time the TEP signals were so strong, he was able to hear them with just the telescopic whip on his TecSun PL398.

Yesterday was a strong FMDX opening vía TEP, I picked "La mega" with a Tecsun PL398 and only it's telescopic antenna. Almost ~5000km from Barranquilla, Colombia to Santiago, Chile. pic.twitter.com/2xSKLuXaBu

— Alejandro (@NautilusCL) November 22, 2021

Back in October, Alejandro was using a log periodic directional antenna outdoors on a mast to hear the signals but to hear FM radio signals on 93.1 MHz on the VHF FM band from 5000kms away with just a telescopic whip is really amazing.

20th October 2021:  Recepción FM DX via TEP (muy fuerte) "La Mega" 93.1Mhz Colombia, desde Stgo, Chile. Reception of 'La Mega' radio station in Colombia on 93.1 MHz by CE3VRT in Chile

Propagation mode: TEP
Distance: Approx 5000kms

"TEP opening (trans-equatorial propagation) very strong and somewhat short. The station tuned is "La Mega" from Barranquilla, Colombia, reception in the southern zone of Santiago de Chile (~ 5000km) using an Airspy HF + dual port and a logarithmic directional antenna for TV / FM."

Reception on Wednesday, October 20, starting at 21:30 PM local time (Oct 21 - 00:30 UTC)

4800km+ opening on the Band 2 VHF band between Chile and Columbia - Sept 2021

In some recent posts, I noted how there was openings on 144 MHz between the Caribbean and Brazil via TEP - Trans-Equatorial Propagation. The distances were in the region of 4600kms.

As can be seen from the graphic above, there was also an interesting TEP opening further west with Band 2 FM signals at 102.7 MHz in the north of Columbia being heard in Chile in early September, a distance of just over 4800kms.

The recording below is from Felip, CE3SAD in Chile who is an avid FM DX-er.

FM radio station on the Azores (87.7 MHz) heard across the Atlantic in Ontario, Canada - 8th July 2021

Thurs 8th July 2021: I reported recently on how a FM radio station on 88.0 MHz in Iceland had been heard near Cape Cod on the NE coast of the USA, a distance of some 3900kms. I can now report that a FM radio station on the Azores was heard in Ontario, Canada on the same day.

At 10:39 UTC on the 8th of July, William Hepburn near Grimsby in Ontario, Canada managed to hear RTP Antena 3 on Ponta Delgada in the Azores on a frequency of 87.7 MHz.

The distance was approximately 4,520 kms which is very close to the limit for double hop Sporadic-E.

William writes... "It took some investigation, podcasts, and a mix-up with Azores vs. Portugal time zones, but I managed to confirm reception of 87.7 RTP-3 Ponta Delgada, Azores (Pico de Barrosa xmtr) here in Grimsby, ON at 6:38-6:40 p.m. EDT July 8th. Top-of-the-band skip to Newfoundland was in at the time."

You can find a recording of what was heard on William's blog post HERE

For this extraordinary catch, William was using an ICOM R-8600 with a CHANNEL MASTER CM-3671 antenna.

Analysis: This is yet another example that Sporadic-E regions with a high maximum usable frequency (MUF) up as far as Band 2 (88-108 MHz) can occur over the North Atlantic. It may be possible that at times, one of the two regions may have a MUF up as high as 144 MHz.

It's interesting to look at the 4500 km circle and seeing how it reaches the Caribbean. 

Is there anyone in the Caribbean listening for FM radio stations on the Azores and the Canary Islands?

Is there anyone on the Azores or the Canary Islands listening for FM radio stations in the Caribbean?

If a FM radio station on Band 2 (88-108 MHz) can be heard then perhaps a contact on 144 MHz might be possible?

Links...
1) My Band 2 page with examples of long distance reception reports.

FM radio station in Iceland on 88 MHz is heard in the USA (3900kms) - 8th July 2021

Thurs 8th July 2021: Over the last few weeks, there have been some remarkable openings on the FM band in the North Atlantic. Links to post HERE

On the 8th of July, there was yet another opening in the North Atlantic when a FM radio station on 88 MHz in Iceland was heard by four individuals in the USA. Three in the state of Massachusetts and one in New Jersey.

21:53 UTC 88.00 MHz RÚV Rás 1, Stykkishólmsbær/Stykkishólmur-símstöð (3,945 kms) 18kW (Bryce Foster (K4NBF), Mashpee, MA, USA)

22:06 UTC  88.00 MHz RÚV Rás 1, Stykkishólmsbær/Stykkishólmur-símstöð (3,921 kms) 18 kW (Jeff Lehmann, Rockland, MA, USA)

The individuals concerned were... Bryce Foster, K4NBF (MA), Jeff ?? (MA), Keith McGinnis (MA) and Nick Langan (NJ).

As can be seen above, the distance was just over 3,900 kms. The likely propagation mode was double hop Sporadic-E (1950 kms x 2). 

However, that part of the Mesosphere where Noctilucent Clouds are found has been shown to reflect radio signals and that can't be ruled out.

One hop Sporadic-E reception on Band 2 over southern latitudes for example in Europe or the USA is really nothing special. When we start getting up into the Arctic regions, it's less obvious what the cause is for long distance VHF signals and that's why these reports are of interest.

Second Spanish station identified on 95.8 MHz in Trans-Atlantic opening on the 21st of June 2021

As outlined in a previous post, Larry Horlick VO1FOG in Newfoundland heard a trans-Atlantic Spanish radio station on 88.8 MHz on the 21st of June 2021. Thanks to recordings that Larry has sent on to me, another Spanish radio station has now been identified.

This one was RNE Radio 3 on 95.8 MHz from the 100 kW transmitter at Navacerrada near Madrid.

The distance to Newfoundland is in the region of 3940 kms and it was very likely to have been due to double hop Sporadic-E as outlined in the previous post.

As well as the distance being 200 kms or so longer, it's interesting to note that the maximum usable frequency (MUF) for this double hop trans-Atlantic path was 7 MHz higher and well into the Band 2 broadcast band.

This is a recording of the signal on 95.8 MHz as it was heard in Newfoundland...

John, EI7GL · 2021 - Jun - 21 12 03 43 95point8

This matches the podcast for the RNE Radio 3 programme on the day. Link HERE

Credit: Thanks to FM DXer Paul Logan in the north of Ireland who helped identify this station and who also heard a FM radio station in Quebec during the same opening.

Sporadic-E footprint: It's interesting to see how the path from Madrid to Newfoundland is almost exactly in line with the other reception of the RNE R5 station on 88.8 MHz near Zamora. 

Sporadic-E openings on the 88-108 MHz band are often like this with the stations heard stretched out in a straight line.

In Conclusion: I have covered the likely propagation mode in the earlier post which is HERE. As well as the distance and frequency of this second report, I am also struck by it's symbolism. 

If a FM transmitter on 95.8 MHz serving Madrid, the capital of Spain can be heard across the North Atlantic in Newfoundland then what can FM Dxers and other radio enthusiasts in the Iberian Peninsula hear from North America?

And on a final note. Larry observes that there were MANY other radio stations in Spanish during this opening. We were able to identify just two from the audio recordings.

Mystery Station: There is a third and final recording but it's just a song. 

It is the song 'Black Velvet' from Alannah Myles and it was heard from 11:55 UTC to 11:59 UTC on 89.9 MHz. Station? Location?

* * *

Update - 27th June 2021: The mystery third station has now been identified as Los 40 Classic. A visitor to the blog (FinnDX) saw the comment above about the mystery station and then used this website to check back through the playlist of stations for the last week... https://onlineradiobox.com/

This is a composite of a screen capture that I took before it disappeared. The website seems to be showing what the time was in my location which is an hour ahead of UTC during the Summer months.

12:54 Irish time = 11:54 UTC.

This is a 2kW transmitter located at Segovia which is just to the north-west of Madrid.

Spanish radio station on 88.8 MHz heard across the Atlantic in Newfoundland, Canada - 21st June 2021

Back on the 21st of June 2021, Paul Logan in the north of Ireland confirmed that he had heard a FM radio station across the Atlantic near Quebec City in Canada on 90.7 MHz.

I can now confirm that Larry Horlick, VO1FOG in Newfoundland, Canada managed to hear RNE-R5 Todo Noticias in the north-west of Spain on 88.8 MHz on the same day!

This is I believe the very first reception of a European FM station station on the 88-108 MHz band in North America.

It looks as if the signal came from the 80 kW transmitter near Zamora in Spain and the distance was in the region of 3780 kms.

I have two recordings which Larry very kindly sent on. The first one is at 11:46 UTC...

John, EI7GL · 2021 - Jun - 21 11 46 12 88point8

In the above recording, the cities of Zamora, Segovia and Burgos are mentioned. It would seem as if this is from the Castilla y Léon regional news bulletin which runs from 13:10 to 14:00 Spanish time.

This is the second audio recording at 11:50 UTC...

John, EI7GL · 2021 - Jun - 21 11 50 26 88point8

This one is a bit more noisy but the distinctive little 'jingle' between the news items can be heard.

Credits: I must thank Paul Logan in Ireland and Jorge Garzon in Spain for confirming that these were  indeed recordings of the RNE-R5 Todo Noticias radio station and that the transmitter site was near Zamora. Both are very experienced FMDXers and it's great to have their expertise to call on to make sure there was no mistake.

Newfoundland: On the receive side, Larry Horlick was using an ICOM IC-R8500 receiver with a centre-fed vertical dipole at 18m above ground level, cut for the lower end of the VHF LO TV band (essentially, non-resonant on Band 2).

Larry has only been listening seriously on the 88-108 MHz bands for a few weeks and he has already managed an incredible reception report. As well as being in a relatively quiet location (FM wise), he does have the advantage of being at the most eastern pat of Canada. 

It also helps that anything that Larry hears on the 88-108 MHz band is likely to be in English or French so any other language really stands out.

Propagation Mode: It seems very likely that this was a case of double hop Sporadic-E at 88.8 MHz.

The above diagram shows the signals 'bouncing' off Sporadic-E clouds at about 110kms above ground level and being reflected off the ocean at the mid way point. It's possible that this was also chordal hop with the signal going directly between the two Sporadic-E clouds without hitting off the Earth.

Note that the angles and height of the Sp-E cloud in the above diagram are greatly exaggerated. In reality, the angles are very shallow and are probably just a few degrees above the horizon.

This is another diagram showing the suggested path and the two Sporadic-E regions.

Paul Logan in the north of Ireland reports that he was hearing FM radio station from the Azores Islands for about five hours that day which he says was highly unusual. The MUF went up as high as 104 MHz.

It's likely that the Sporadic-E region responsible for the Azores to Ireland path was also responsible for the eastern first hop of the trans-Atlantic path between Spain and Newfoundland.

It's seems as if this eastern Sp-E region was present for several hours and it just required one Sp-E path at the right spot on the western part of the path to complete the 2 x 1890 km circuit.

In Conclusion: This really is an amazing reception report and is part of radio history in that it is the first proven reception of a European FM station on Band 2 in North America.

It also raises some interesting questions...

1) If someone in Newfoundland can hear a FM radio station in Spain then why can't FM radio stations in Newfoundland, Nova Scotia, Quebec and Maine be heard in Spain and Partugal?

2) If a Sporadic-E cloud in the western part of Atlantic can support a signal at 88.8 MHz then can it reach 144 MHz at times? And if so, could it couple into a tropo duct of say 1500 kms to complete the path to Spain or Portugal?

A double hop Sporadic-E trans-Atlantic path at 144 MHz is highly unlikely but a mixed Sp-E / Tropo propagation mode is much more likely.

The best thing about this trans-Atlantic reception report is that it now 'opens the door' on what might be possible. My hope is that it now raises awareness and more people will now listen for trans-Atlantic signals on the 88-108 MHz and 144 MHz bands.

Larry, VO1FOG informs me that he is building a 10 el K6STI Yagi for 88-108 MHz so hopefully we will get to hear of some more trans-Atlantic signals.

Addendum: This is a photo of the vertical Band 1 dipole that was used for the reception.

Analysis of Paul Logan's Band 2 FMDX log for 2020: Pt 1 - Tropo

In this three part series of posts, I am going to look at the 2020 logs of a very active Band 2 DXer and what they might suggest about propagation on the 88 to 108 MHz FM band. The posts are broken up into three parts... 1) Tropospheric Propagation, 2) Sporadic-E & 3) Meteor Scatter.

First off, a big thank you to Paul Logan who very kindly shared his 2020 Band 2 logbook with me and answered numerous questions that I had. Outside of his usual 'local' FM radio stations which he can hear under flat conditions, he logged and identified roughly 5,500 long distance signals on Band 2 in the year 2020.

Profile of Paul Logan... Paul is a very active listener of Band 2 radio (88-108 MHz) signals and has been logging stations that he has heard for about 30 years. He lives in Lisnaskea in Co.Fermanagh in Ireland and his location is shown in the map below.

Paul's location is far from ideal for listening to distant VHF signals. He has some local hills to the east as well as the hills and mountains in Scotland, England and Wales as a further obstruction.  

Equipment... For the 2020 logs, Paul used an SDRPlay RSP1 & RSP1A.

In recent years, software defined receivers have transformed FMDX listening as signals can now be seen on a computer screen as well as being heard. This allows a user to visually check for any unusual signals and can then go investigate it. One of the most impressive features is the ability to record sections of the spectrum and a user can then go back later to listen for anything unusual.

For an antenna, Paul is using a Korner FM9 from Antennenland in Germany.

This antenna which is mounted 8 metres above ground level is highly regarded by many FMDXers in Europe.

2020 Tropo Log... During the year 2020, Paul heard and identified around 86 signals that were heard via tropospheric propagation. This mode of propagation occurs when signals are bent over the horizon by sharp changes between air layers with different temperatures and moisture content.

I have picked out 5 groups of signals of note which I have marked from A to E. Refer to the map below and then the horizon profile further down.

A - This group of signals from the north-west corner of Spain are in the region of 1200 to 1300 kms. The sea path from the south coast of Ireland to the north coast of Spain is very good for VHF propagation with marine ducting happening several times a year. These sea paths are usually the best for very long paths in excess of 500kms and sometimes the signals can be amazingly strong.

In the video below, Paul shows how he was able to hear a Spanish radio station on a small portable radio when the opening was at its strongest. With his main directional antenna, he was able to hear the Spanish signals for most of the day.

In the horizon plot below, you can see that the path to NW Spain at Paul's location is largely unobstructed with only a 1 degree elevation. This allows very low angle signals to arrive at his location.

B - This path to Brittany and Cornwall is similar in that the sea path helps and the hills on the horizon are quite low at about 1 degree elevation.

C - This interesting batch of signals came from Norfolk in the east of England, a distance of 600kms. These signals had a few obstacles to overcome including Paul's local hills as well as the Pennines running down the centre of England.

With the signals arriving at least 3.5 degrees above the horizon, the means of propagation may have been via an elevated duct in the region of 500m to 2000m above the earth's surface. While higher frequency VHF & UHF signals tend to propagate better inside of ducts, it went as low as 89.7 MHz in this example.

D - This cluster of signals from the Netherlands and Germany were interesting for a number of reasons. First off is the sheer distance... about 1000kms which is unusual for Band 2 tropo. I suspect that the sea path over the North Sea may have helped for a large part of the journey.

If you examine the horizon plot below, you'll notice that there is a gap in the hills due east (90 degrees) where the horizon has an elevation of about 2.5 degrees.

What's really interesting is that the paths from the four transmission sites fit exactly in the gap. The signal from the most northerly German transmitter is exactly at the left hand side of the gap. The signal from the most southerly Dutch transmitter is exactly at the right hand side of the gap. The four signals fit exactly like a glove which suggests that they are coming in just barely above 2.5 degrees above the horizon.

E - These signals from the Newcastle area were at a distance of about 370kms and again are coming in from an obstructed path. This one has the highest angle as it had to clear a local hill that was 4 degrees on the horizon.

Outside of the five examples shown above, most of the other signals were in the region of 150 to 300kms which is pretty typical for tropospheric propagation on Band 2.

What's also interesting are the signals that weren't heard. For example, there was no tropo from Scotland which Paul confirms is a very difficult direction for him. As can be seen from the horizon plot above, the local hill in that direction is 5 degrees and that has the effect of blocking tropo signals.

In conclusion... I hope this short analysis highlights the importance of having a low unobstructed horizon for hearing signals on Band 2 (88-108 MHz). 

Having obstructions under 1 degree is best, under 2 degrees is acceptable but beyond that, the signals and paths get rarer.

Any local hill that is at 5 degrees or above is a show stopper for VHF tropo propagation.

The examples above would also apply to say the VHF aircraft band (118-136 MHz), the 2-metre amateur band (144 MHz) and the VHF marine band (156 MHz). 

Normally the best advice is to have your antenna mounted as high as possible on the VHF bands so that the amount of obstruction on your horizon is reduced to a minimum. 

Band 2 is a bit of an paradox in that the higher you put your antenna, the 'local' signals get stronger which in turn can mask the DX signals. It's really a case of finding out what height works best for your location.

Links...

1) Paul Logan's Tropo log for 2020 on the FM List website.

2) Paul's YouTube Channel

3) Paul's radio website

4) Paul's AM/FM DX Twitter account