Friday, July 31, 2020

4000km plus opening on 144 MHz & 432 MHz from Cape Verde to NW Europe - 30th July 2020

30th July 2020 - There was another impressive 4000 km plus opening on the VHF & UHF today from Cape Verde Islands off the west coast of Africa to the north-west of Europe.

The map above from PSKReporter shows the FT8 signals being sent and received by D4VHF in Cape Verde. The mode of propagation was the usual marine duct but it was unusual to see the conditions extend into the midlands in England.

One of the most unusual reception reports was from PB0AHX in the Netherlands for two reasons.

1) The distance at 4680 kms is just 100kms short of the IARU Region-1 tropo record which was from D4VHF to the Isle of Skye in January of 2020.

2) The path from the Netherlands was over a lot of France and parts of Spain raising the possibility that perhaps there was another mode of propagation at work for the northern part of the path such as Sporadic-E or Meteor Scatter?

These are the FT8 reports on 144 MHz in order of distance for NW Europe...

Txmtr Rcvr Band Mode Distance Time (UTC)
D4VHF PB0AHX 2m FT8 4680 km 12:50:44
D4VHF M0CTP 2m FT8 4622 km 15:58:14
D4VHF G4BNM 2m FT8 4582 km 15:47:42
D4VHF GM3SEK 2m FT8 4562 km 14:29:44
D4VHF GD3YEO 2m FT8 4503 km 13:07:14
D4VHF G4CLA 2m FT8 4473 km 09:24:44
D4VHF G8VHI 2m FT8 4466 km 12:08:41
D4VHF G4KWQ 2m FT8 4462 km 16:36:11
G0CUZ D4VHF 2m FT8 4440 km 10:43:27
MW1CFN D4VHF 2m FT8 4438 km 11:04:57
G8TIC D4VHF 2m FT8 4411 km 12:15:27
D4VHF GW4SHF 2m FT8 4404 km 15:41:14
D4VHF M0BUL 2m FT8 4388 km 15:32:14
M0BUL D4VHF 2m FT8 4388 km 15:32:57
D4VHF G0JCC 2m FT8 4362 km 16:40:41
D4VHF GW7SMV 2m FT8 4317 km 16:52:44
D4VHF GW4HDF 2m FT8 4312 km 18:48:14
D4VHF GW4VXE 2m FT8 4280 km 09:55:41
D4VHF GW0KZG 2m FT8 4276 km 16:54:14
D4VHF GW1JFV 2m FT8 4264 km 10:16:41
D4VHF EI8KN 2m FT8 4230 km 13:29:11
D4VHF G4RRA 2m FT8 4211 km 16:44:14
D4VHF EI2FG 2m FT8 4182 km 19:11:41
D4VHF M0BKV 2m FT8 4181 km 18:49:44
D4VHF EI3KD 2m FT8 4170 km 19:26:14
G4ALY D4VHF 2m FT8 4160 km 12:07:57
D4VHF G8IXN 2m FT8 4110 km 13:30:44
D4VHF G4LOH 2m FT8 4098 km 19:43:14
M0AFJ D4VHF 2m FT8 4094 km 18:43:57
D4VHF G3NJV 2m FT8 4090 km 14:02:44
D4VHF G7RAU 2m FT8 4086 km 19:33:41
D4VHF F6DBI 2m FT8 4020 km 16:54:44
D4VHF F6KHM 2m FT8 3966 km 10:23:44
D4VHF F8DBF 2m FT8 3963 km 19:38:14

The tropo prediction map below from Pascal, F5LEN shows the sea path from Cape Verde... 

70cms... The sea path was also open at 432 MHz.

Rcvr Band Mode Distance Time (UTC)
EI3KD 70cm FT8 4170 km 10:12:14
G3NJV 70cm FT8 4090 km 13:03:14
G7RAU 70cm FT8 4086 km 19:16:11
F8DBF 70cm FT8 3963 km 22:08:44
EA1FBU 70cm FT8 3224 km 18:56:44
EA1YV 70cm FT8 3201 km 19:04:14
EA7SL 70cm FT8 2885 km 19:38:44
EA8CSB 70cm FT8 1562 km 19:15:14
EA8AR 70cm FT8 1546 km 11:12:11
EA8RH 70cm FT8 1512 km 20:45:11

It's always amazing to see a 4000 km plus path at 432 MHz.

Canary Islands... It's also worth mentioning that the sea path was also open from the Canary Islands to NW Europe...

G7RAU 432174.0 EA8CSB 18:15 30 Jul IN79JX IL18TL cq, gl Canary Islands
G7RAU 144485.0 ED8ZAA/B 17:48 30 Jul IN79JX IL18UM 599+10 Canary Islands
G7RAU 144320.0 EA8BPX 17:46 30 Jul IN79JX IL18SK 59++ gl Canary Islands
GM4FVM 144174.0 EA8CSB 17:39 30 Jul IO85WU IL18TL Hrd CQ -11dB Canary Islands
MM0CEZ 144174.0 EA8CSB 17:01 30 Jul io75xu IL18 FT8 -19 dB tnx Canary Islands
M1GSM 144174.0 EA8CSB 16:50 30 Jul IO94DR IL18TL RX -20 GL Canary Islands
G4RRA 144174.0 EA8CSB 16:02 30 Jul IO80BS IL18TL Canary Islands
F6FGQ 144485.0 ED8ZAA/B 10:52 30 Jul 529 stable in IN78QJ Canary Islands
G4ALY 144485.0 ED8ZAA/B 10:44 30 Jul IL18UM(TR)IO70VL 549 Canary Islands
EI3KD 144485.4 ED8ZAA/B 05:45 30 Jul IO51VW IL18UM 599+ Canary Islands

Let's have a look at the PSKReporter map for EA8CSB on 144 MHz for the 30th of July 2020...

Note that many of these paths are in excess of 3000kms,,,

Txmtr Rcvr Band Mode Distance Time (UTC)
EA8CSB GM0HBK 2m FT8 3287 km 15:50:14
EA8CSB GM4FVM 2m FT8 3248 km 19:01:41
EA8CSB MM0CEZ 2m FT8 3197 km 17:19:14
MM0CEZ EA8CSB 2m FT8 3197 km 17:17:29
EA8CSB 2M0ETJ 2m FT8 3135 km 17:58:44
2M0ETJ EA8CSB 2m FT8 3135 km 17:17:59
EA8CSB GM3SEK 2m FT8 3073 km 17:04:44
GM3SEK EA8CSB 2m FT8 3073 km 16:04:59
EA8CSB GI4SNA 2m FT8 3013 km 17:35:44
EA8CSB GI6ATZ 2m FT8 3002 km 17:56:41
EA8CSB G0SYP 2m FT8 3001 km 17:20:41

It's always worth remembering that the distance across the North Atlantic from Ireland to Newfoundland is about 3000 kms.

1) F5LEN Tropo Prediction

Wednesday, July 29, 2020

Article on using FT8 for Moonbounce on 1296 MHz...

Bacn in May of 2020, I had a post up about the first Moonbounce /EME (Earth-Moon-Earth) contact on 432 MHz by using the FT8 digital mode.

I recently came across another detailed article by KA1GT on using FT8 for Moonbounce on 1296 MHz.

Besides the very weak signals, one of the problems that FT8 has to deal with is the time delay of about 2.4 to 2.8 seconds for the signal to go from the Earth to the Moon and back to the Earth again. Signals on the HF bands by comparison are almost instantaneous.

As you can see from the waterfall display above, the signal from the Moon is delayed and falls outside the usual 15 second window for decoding.

The article covers how this delay is dealt with and concludes that the FT8 digital mode is suitable for strong signals on 1296 MHz and allow a contact to be completed up to four times faster than using the more usual JT65C mode.

You can view the article HERE

Monday, July 27, 2020

Videos about VDSL Broadband interference

VDSL (Very-high-bit-rate Digital Subscriber Line) is currently the main way to deliver broadband to  residential customers in the UK. A similar ADSL system is used in Ireland.

VDSL uses the existing twisted-pair traditional telephone cables to carry high speed broadband data signals between the network provider’s “cabinet” (typically an above ground street-furniture box) and the customers premises.

The frequencies used in the UK are shown below...

The problem however is that the existing telephone cables were only supposed to carry a simple telephone signal in the audio spectrum up to several kHz and not signals of several MHz. As a result, VDSL broadband signals can cause widespread interference as seen in the plot below...

VDSL interference to the 7 MHz (40m) & 10 MHz (30m) bands
Videos... Two videos featuring presentations by John Rogers, M0JAV have been uploaded to YouTube recently.

The first one on the Mid-Ulster Amateur Radio Club account outlines what VDSL is and ways to deal with interference...

The second one on the Radio Society of Great Britain (RSGB) account describes VDSL and how people in the UK can complain to OFCOM, the UK regulator...

For further reading, RSGB have provided some additional information...

RSGB Frequently Asked Questions about interference

VDSL Interference Reporting

VDSL Interference Advice Leaflet

Saturday, July 25, 2020

144 MHz Weak Signal Ionosphere Scatter

One of the more unusual propagation modes on the VHF bands is Ionosphere Scatter or 'Ionoscatter' for short.

To establish contact, both stations at either end of a link usually run very power into very large antenna systems with a lot of gain and beam at a common point in the D layer of the ionosphere which is about 85 kms above the earth.

It is similar in many ways to troposcatter except the greater height allows a much greater range. With troposcatter, the scatter point in the troposphere may be in the region of several kms above the earth e.g. 9kms for a 500 km path.

For ionoscatter, the radio signal is scattered forward by small changes in the ionization density in the ionosphere at a height of about 100kms or below with a peak at 85 kms. This gives a typical range of about 800 kms to 2000 kms with a peak around 1300 kms.

Ionoscatter works best at the low VHF part of the spectrum (30-50 MHz) although under the right conditions, it can be used at 144 MHz as well.

RSGB Video... Traditionally, ionoscatter contacts were the preserve of stations running very high power to large antenna arrays and using CW.

Now with the advent of new digital modes, the entry level for this mode of propagation is lower and it's possible that many people have already made ionoscatter contacts and were not even aware of it.

At the 2019 RSGB Convention, Richard, G4CDN gave a talk titled "2m Weak Signal Ionosphere Scatter". In it, he gives an outline of his experience of ionoscatter and advocates the use of the QRA64 digital mode.

Additional info...
1) Ionoscatter lecture from 2002 by OZ1RH

Thursday, July 23, 2020

4000km VHF opens up from NW Europe to Cape Verde Islands - 22nd July 2020

Over the last few days, there have been another opening from the north-west of Europe on the VHF and UHF bands to Cape Verde Islands off the west coast of Africa. The map above shows the opening on 144 MHz on the 22nd of July 2020 with many of the FT8 signals from D4VHF around the 4000 km mark.

xmtr Rcvr Band Mode Distance Time (UTC)
D4VHF GW4VXE 2m FT8 4280 km 19:01:11
D4VHF GW1JFV 2m FT8 4264 km 21:31:14
D4VHF GW6TEO 2m FT8 4249 km 20:44:14
D4VHF EI8KN 2m FT8 4230 km 20:57:11
D4VHF EI2FG 2m FT8 4182 km 19:51:41
D4VHF M0BKV 2m FT8 4181 km 22:49:14
D4VHF EI3KD 2m FT8 4170 km 22:22:14
D4VHF G4LOH 2m FT8 4098 km 23:26:14
M0AFJ D4VHF 2m FT8 4094 km 19:52:26
D4VHF G3NJV 2m FT8 4090 km 21:34:14
D4VHF G7RAU 2m FT8 4086 km 23:25:11
D4VHF F6KHM 2m FT8 3966 km 22:25:14
D4VHF F8DBF 2m FT8 3963 km 22:39:14
F6DRO D4VHF 2m FT8 3870 km 15:30:26

The path was also open on 432 MHz...

As with previous openings of this type, the path is marine ducting. There seems to be almost a permanent 3000 km path from Cape Verde to Spain & Portugal at certain times of the year and this pushes northwards towards the UK and Ireland from time to time.

Just to give an idea of how good this opening was, Tim GW4VXE in the far SW of Wales reports hearing D4VHF on 70cms with a vertical!

It would be really interesting to see if this path extends up into the microwave bands, especially on 1296 MHz.

Wednesday, July 22, 2020

Articles about using Ferrite Cores as RF chokes

Ferrite cores are used everywhere in radio from RF transformers to filters to chokes. They are often made from different materials that will have different properties at different frequencies and they are often seen as a bit of a Black art.

I came across some recent articles on using ferrite cores as RF chokes and I'm posting the links here so I don't lose them.

1) QRM GURU : The truth about ferrites... This website looks at a selection of ferrite cores and how they can be use to prevent interference at HF & VHF.

2) K9YC ... This website has a detailed PDF on using ferrite cores as RF chokes.

Monday, July 20, 2020

Australian authorities turn down request for 70 MHz allocation

There was a news item on the Internet recently about how the Australian regulator was not considering an allocation at 70 MHz for radio amateurs.

“We note the continued interest in this band from the amateur community. The ACMA will not be further investigating this matter at this time.

The ACMA considers that operating amateur services in this frequency range is not feasible as it would be inconsistent with ITU Radio Regulations and existing services are already operating in the frequency range. 

This frequency range is used by a variety of fixed and land mobile services as supported under the VHF mid band (70–87.5 MHz). Class licensed devices authorised under the LIPD Class Licence operate in the frequency range 70–70.24375 MHz.”

This was the reply to a submission to an earlier submission by the Wireless Institute of Australia (WIA) to the ACMA which essentially consisted of a single sentence... "10. The WIA still has an interest in an allocation at 70 MHz."

ITU Region 3... As can be seen from the map below, Australia is in ITU Region 3 while nearly all of the 70 MHz allocations are in Region 1 countries.

It's a pity that something like a 4m beacon couldn't be established in Australia or even a or a few experimental licences for the band.

It would be interesting to see if say someone in Perth on the west coast (VK6) could investigate if there is a multi-hop Sporadic-E path across the Indian Ocean to South Africa or up to the Middle East.

What would be good is for one of the smaller countries in Region 3 to give a small allocation for the 4m band which would then set a precedent. Even a 200 kHz wide segment of spectrum dedicated to weak signal modes would satisfy most requirements.

Saturday, July 18, 2020

Video: Transceiver performance for the HF - VHF - UHF operator... by NC0B

The Sutton and Cheam Radio Society recently uploaded a video on YouTube titled Transceiver performance for the HF - VHF - UHF operator.

No matter what bells and whistles a radio has, the most important parameter is how it performs on the air in terms of reception and transmission of signals.

The presentation is given by Rob Sherwood, NC0B and it goes into quite a bit of technical detail on how to judge the RF performance of a transceiver on the HF or VHF bands.

Some key points...

  • Sensitivity isn't the most important parameter on HF
  • Low signal performance is often determined in modern times by urban noise
  • While a dynamic range of 100dB is common on HF, it's usually a lot worse on 2-metres and above
  • 2m & 70cms tranceivers are 10-25 years behind HF versions

If you are serious about getting the most from your station then it's well worth watching.

Fast forward to 2:45 for the start of the presentation...


Friday, July 17, 2020

What is the IARU??

The IARU is the International Amateur Radio Union and it represents the interests of radio amateurs worldwide at international conferences and with national regulators through the various national societies.

A 3-minute promo video outlining their work can be seen HERE

The national society for radio amateurs in Ireland is the IRTS - the Irish Radio Transmitters Society.

Thursday, July 16, 2020

Unusual Sporadic-E opening on 144 MHz in N Europe hints at possibility of Trans-Atlantic contact

In this post, we'll look at a recent Sporadic-E opening on 144 MHz in northern Europe and what it might mean for a trans-Atlantic contact on 2 metres.

First, the opening...

There was an extensive opening on 144 MHz on the evening of Monday the 13th of July 2020 as can be seen from the graphic above from DXMAPS.COM

Sporadic-E openings on 144 MHz are reasonably common in Europe but they are usually much further south. Radio amateurs in say the UK or Ireland are likely to catch several openings to say Spain or Italy during the months of May, June and July every year.

It is very unusual to have a Sporadic-E in northern Europe and it is rare for the radio amateurs in the UK or Ireland to hear the likes of Finland or the Baltic states on 144 MHz via Sporadic-E.

While the graphic above gives an illustration of the extent of the opening, let's have a look at some specific examples. The maps below generated by FT8 reports on the PSKReporter website are useful for examining the extent of the opening.

EI2FG on the south coast of Ireland was one of the most westerly stations listening on the FT8 frequency on 144 MHz for the opening.

The longest path was to UA1ALD at 2416 kms and the signal was +9dB which was certainly strong enough for an SSB contact. Note the beam heading... 55 degrees. OH6KTL was up at 44 degrees.

Note also that the path was open only to the northern part of Estonia, there was nothing further south.

UA1ALD... This is the FT8 sent/receive map for UA1ALD.

Note how concentrated the footprint is in the UK. There is no-one from the south-east of England shown.

ES4RM... Note how the results for ES4RM in the north of Estonia are pretty much the same with nothing from the south-east of England.

OH2FQV... This is the map for OH2FQV in the south-east of Finland.

Note the difference in the footprint in the UK compared to UA1ALD. This time, there are a lot more stations in the south-east of England except for an area south of London.

This suggests that the Sporadic-E cloud responsible for the 144 MHz opening was probably somewhere over the north of Denmark. What each station worked or heard was dependent on where they were relative to this Sporadic-E hot spot.

It's also amazing to see just how many stations in England are using FT8 on 144 MHz!

GI6ATZ... This is the map from GI6ATZ in the north-east of Ireland.

The more northerly location of GI6ATZ results in stations in Lithuania and Latvia being heard.

G7RAU... The send/receive map for G7RAU in the south-west corner of England shows that there was a 2445 km path open to OH6CT in the north of Finland, just three degrees or so south of the Arctic Circle.

Again, note the beam heading from G7RAU to OH6CT which was 35 degrees. The signal was -2dB which would have been enough for a CW contact.

OH6CT... From OH6CT's viewpoint, he was hearing the south-east of England this time and the rest of the UK and Ireland was missing.

Trans-Atlantic on 144 MHz??? .....First of all, lets recap.

a) Both G7RAU and EI2FG heard or were heard by stations on FT8 in Finland at beam headings of 35 and 44 degrees respectively i.e. very far to the north.

b) Both G7RAU and EI2FG heard or were heard at -2dB and +9dB respectively at a distance of about 2400 kms. Note that this is about the maximum distance for one hop Sporadic-E.

Now lets look at the path from St.John's in Newfoundland to the south-west of Ireland and the north-west of Spain.

First off, the beam headings of 68 and 80 degrees are a lot further south than the beam headings experienced by EI2FG and G7RAU. If there is a Sporadic-E opening on 144 MHz in the north of Europe then why wouldn't it also happen out over the North Atlantic?

I know some might argue that Newfoundland is closer to the geomagnetic pole and that might impact on Sporadic-E formation but Newfoundland is also further south than Ireland.

While the one hop of 2400 kms ends up in the Atlantic, the remaining distance to span isn't huge. Just another 800 kms or so would reach the south-west of Ireland. Just another 1000 kms would reach Spain. Both of these distances could be easily bridged by a tropo duct forming over the ocean to the west of Ireland or Spain.

Surely there must be times when there are Sporadic-E openings on 144 MHz to the east of Newfoundland? And there must be times when these openings coincide with tropo over the eastern part of the Atlantic? I would argue that there must be times when the path across the North Atlantic on 144 MHz is open although I would acknowledge that these openings are pretty rare.

I'd suggest that one of the biggest problems is the lack of activity on the western end. I don't believe there is anyone in Newfoundland transmitting or listening on 2-metres for signals across the Atlantic. For all we know, some of the trans-Atlantic CW beacons in Ireland, England or France may well have made it across the ocean to Newfoundland but there was nobody there listening to report it.

Look at the distance from Newfoundland to the Azores (CU). That's within Sporadic-E or meteor scatter distance and yet as far as I am aware, there has never been a contact on 144 MHz from Newfoundland to the Azores.

Solution... The most obvious one to me is the establishment of a station on Newfoundland that can be operated remotely, just like D4VHF on the Cape Verde Islands. Something like two stacked 5-element Yagi antennas beaming at 70 degrees with 100 watts?

Digital modes like FT8 could be used to see if the path was viable by transmitting and receiving on the 2-metre frequency of 144.174 MHz.

It is of course easy to say how it might happen, it's another thing for a group to implement it.

Monday, July 13, 2020

IC7300 online jigsaw

This might be one for when the bands are closed 😊

There is an online jigsaw for the ICOM IC-7300 at this LINK

Sunday, July 12, 2020

3000km plus contact on 144 MHz from St.Helena to South Africa - 4th June 2020

There are several areas around the world where there are some amazing propagation paths on VHF due to ducts forming over the ocean. One of these seems to happen occasionally in the South Atlantic off the coast of South Africa.

On the 4th of June 2020, there was a successful FT8 contact on 144 MHz between ZS1FC near Cape Town in South Africa and ZD7GWM on St.Helena.

The distance was in the region of 3,040 kms which about the same distance as from Ireland to Newfoundland across the North Atlantic.

Back in November of 2018, ZD7GWM managed to work some ZS3 stations who were further north on the coast and the distance was about 2,700 kms. This new contact with ZS1FC is about 300 kms further.

Friday, July 10, 2020

IARU Region-1 to discuss possibility of 40 MHz & 60 MHz allocation

Every few years, the member societies of the International Amateur Radio Union (IARU) meet up to discuss various proposals and plans. Due to the COVID-19 pandemic, there will be a virtual meeting online of the IARU Region-1 (Europe, Middle East & Africa) in October of 2020.

One of the proposals for the meeting is to discuss the possibility of a 600 kHz wide allocation at 40 MHz and 60 MHz.

1) Conference website
2) Documents

Thursday, July 9, 2020

ESA: How to get pictures from the International Space Station via amateur radio

The European Space Agency have just released a video on YouTube explaining how to receive Slow Scan TV pictures via amateur radio.

The first video is about how to find the International Space Station...

There are plenty of videos about SSTV but this one is aimed at the general public who might never have heard of amateur radio before. The video instructs viewers how to receive pictures using a web based SDR in the SW of England.

This second video shows what software to use to decode the SSTV signals from an online SDR. This one is for those that use the Windows 10 operating system on their PC..

There are similar videos for users of other operating systems.

See the links below...
Windows 7...
Mac OSX...
Rasberry Pi OS...

Tuesday, July 7, 2020

COMREG release Radio Frequency Plan for Ireland - July 2020

The Irish communications licencing authority COMREG have just released a document titled 'Radio Frequency for Ireland'.

You can download it HERE

Sunday, July 5, 2020

Upgrade of the D4VHF station VHF & Microwave antenna systems

Over the last few years, the D4VHF station in the Cape Verde Islands has made some amazing contacts on the 144 MHz & 432 MHz bands across the Atlantic to the Caribbean and also well into Europe. Most of these VHF and UHF contacts are in the region of 3000 to 6000 kms.

They recently made some major changes to their antenna system for 2-metres, 23cms and 12 cms.

2-metres... Up to recently, the D4VHF team were using a single 12 element Yagi on 144 MHz. They have now installed three crossed 5-element Yagis.

The photo above shows the three new 144 MHz crossed Yagis marked A, B and C. As can be seen, the three crossed Yagis are stacked vertically.

This second photo above shows the stacked Yagis from a different angle. Each individual crossed Yagi is made of two 5-element beams in a X configuration. These two beams are  fed 90 degrees out of phase relative to each other and this achieves Right Handed Circular Polisation (RHCP).

Comparison - Old 12 element Yagi V New Stack of three 5-element RHCP Yagis... How do the two antenna systems compare? Here are some rough calculations...

Gain... The old 12 element Yagi which was horizontally polarised probably had a free space gain of about 13dBd.

As for the new stack? Let's take the gain of 5 element beam to be 9dBd. There is a stack of three so lets add 5dB giving a gain of 14dBd. Lets assume that there is some loss stacking as they will probably not get the full three times power so we'll subtract 0.5dB giving 13.5dBd. There is also a 3dB loss due to the fact that it is using circular polarization and we're down to about 10.5dBd.

So we have an estimated 13dBd for the old 12 element and 10.5dBd for the new antenna system, a drop of about 2.5dB.

Linear Vs Circular Polazation... When both the receive and transmit antennas are horizontally polarized at either end of a propagation path and nothing changes then everything is fine. However when the path is several thousand kms in length, will it always stay the same? If there happens to be a Sporadic-E hop involved then the polarization of the signal is constantly changing.

If say a horizontally polarized antenna receives a horizontally polarized signal then there is no loss i.e. 0dB. If however a signal gets twisted and arrives at more than 45 degrees relative to the receive antenna, then the losses can be anything from -3dB up to -20dB.

With very weak FT8 signals buried in the noise and with 15 second transmissions, this polarization fading can mean incomplete contacts or at the very least, it slows things right down resulting in fewer contacts during say a Sporadic-E opening.

With a circularly polarized antenna, the loss is never more than -3dB. So even though the gain of the new antenna stack is slightly less, the lower loss due to polarization changes should result in more completed contacts.

Beamwidth... The other change between the new and old systems is the beamwidth.

The beamwidth of a beam is measured by its -3dB points i.e. where the gain of the antenna has dropped by 3dB.

For the old 12 element antenna with a gain of about 13dBd, the beamwidth was about 32 degrees.

With the new antenna array, the vertical stacking will compress the radiation in the vertical plant and direct more of it down towards the horizon. For the radiation in the horizontal plane i.e. left/right, it should have pretty much the same beamwidth as a single 5 element which is about 54 degrees.

This map shows the beam headings from Cape Verde to Europe...

With the old 12 element pointing at 35 degrees, the 32 degree beamwidth covered about 19 to 51 degrees.... roughly from Wales to the south of Italy.

With the new array for the same 35 degree example, the 54 degree beamwidth will extend from 08 to 62 degrees. This means that there is more power heading towards say Ireland, Scotland and the Azores.

It also allows more power to head towards the Eastern Mediterranean. It seems unlikely that someone from say Greece or Israel could work D4VHF on 144 MHz as there is a lot more land and less sea for a marine duct. But that's not to say its impossible, especially at this more southerly latitude.

Microwave Bands.... They also made some improvements to their set up for the microwave bands of 23cms and 13 cms.

The photo above shows the 1-metre homemade dish for 1296 MHz and 2300 MHz. The gain on 23cms is approx 19dBd while the gain on 13 cms is about 24dBd. They will be adding an elevation motor so that it can be used for moonbounce.

This is another view of the same dish but it also shows the 80cm dish on the right for accessing the QO100 satellite in geostationary orbit (2.4 GHz up, 10 GHz down).

In conclusion... As you can see, the D4VHF team are constantly improving their station on Cape Verde and are opening up new paths that we didn't even know existed.

If you would like to support their work then they have a PayPal link HERE

Friday, July 3, 2020

5000km plus opening on 144 MHz from Cape Verde Islands to Italy, Slovenia & Croatia - 2nd July 2020

On Thursday the 2nd of July 2020, there was another remarkable opening on 144 MHz between Cape Verde Islands off the west coast of Africa and Italy, Slovenia & Croatia.

This isn't the first time that this has happened but any terrestrial opening on 144 MHz which reaches 5000kms or more is always special.

This edited list shows the stations that heard by D4VHF in Cape Verde. It also lists those hearing D4VHF on FT8 but not weren't heard by them (in order of distance)...

Txmtr Rcvr Band Mode Distance Time (UTC)
D4VHF S51ZO 2m FT8 5028 km 19:09:59
9A5BWW D4VHF 2m FT8 5013 km 19:02:42
D4VHF 9A6NA 2m FT8 5013 km 18:51:56
D4VHF S50TA 2m FT8 4885 km 19:17:44
D4VHF S57A 2m FT8 4809 km 18:41:59
D4VHF IV3/HB9CAT 2m FT8 4798 km 18:27:59
D4VHF IV3GTH 2m FT8 4792 km 18:41:56
9A5CW D4VHF 2m FT8 4790 km 19:17:57
D4VHF IV3GBO 2m FT8 4786 km 19:11:44
9A3CX D4VHF 2m FT8 4776 km 19:03:12
D4VHF IV3BLQ 2m FT8 4776 km 19:17:41
D4VHF 9A5CW 2m FT8 4774 km 19:17:14
D4VHF 9A3K 2m FT8 4774 km 19:15:44
D4VHF 9A1UN 2m FT8 4766 km 19:04:29
9A2RD D4VHF 2m FT8 4766 km 19:01:41
IK3VZO D4VHF 2m FT8 4643 km 18:35:12
D4VHF IW3GJF 2m FT8 4639 km 18:35:29
IZ3NOC D4VHF 2m FT8 4636 km 18:32:11
D4VHF IK4DRY 2m FT8 4624 km 18:59:29
D4VHF IK4FMT 2m FT8 4596 km 18:59:26
D4VHF IW4AZY 2m FT8 4548 km 19:11:15
D4VHF IK2MKS 2m FT8 4528 km 15:51:44
IK2LHP D4VHF 2m FT8 4517 km 15:57:56
IK0SMG D4VHF 2m FT8 4506 km 16:44:56
D4VHF IW0FFK 2m FT8 4505 km 16:46:44
D4VHF IZ2MHO 2m FT8 4480 km 15:52:11
D4VHF G7RAU 2m FT8 4086 km 16:02:14

FT8 screenshot from D4VHF
This is a list of the 20 stations in Italy, Slovenia & Croatia that D4VHF actually completed a contact with on FT8...

2020-07-02 15:49:15 IZ2MHO JN45 144.175900 FT8 +03,-06 
2020-07-02 16:30:30 IK0SMG JN61 144.175900 FT8 -03 -11 
2020-07-02 18:25:00 IK3VZO JN55 144.174900 FT8 -19 -01 
2020-07-02 18:28:00 S50TA 144.174900 FT8 +08 +01 
2020-07-02 18:28:30 IZ3NOC 144.174900 FT8 -03 -12 
2020-07-02 18:33:00 IV3NDC 144.174900 FT8 -06 -06 
2020-07-02 18:34:30 IW3GJF 144.174900 FT8 -12 -06 
2020-07-02 18:36:45 IV3GTH JN65 144.174900 FT8 -17 -11 
2020-07-02 18:37:45 IZ3QFG 144.174900 FT8 -05 
2020-07-02 18:42:30 S57A JN65 144.174900 FT8 +02 -06 
2020-07-02 18:44:00 IK4FMT JN54,144.174900 FT8 -15 -21 
2020-07-02 18:46:45 IK4DRY 144.174900 FT8 -11 -07 
2020-07-02 18:52:00 9A3CX JN65 144.174900 FT8 +00 -01 
2020-07-02 18:57:30 9A3K JN65 144.174900 FT8 +05 +01 
2020-07-02 18:58:15 9A6NA JN86 144.174900 FT8 -12 -19 
2020-07-02 19:02:00 9A2RD JN65 144.174900 FT8 +13 -09 
2020-07-02 19:02:45 9A5BWW JN86,144.174900 FT8 -05 -16 
2020-07-02 19:04:30 9A1UN JN65 144.174900 FT8 -10 -07 
2020-07-02 19:05:45 IV3GBO JN66 144.174900 FT8 +17 -07 
2020-07-02 19:12:30 9A5CW JN65 144.174900 FT8 -06 -13 

Another screenshot from D4VHF
Mode of Propagation... How exactly did these 5000km signals travel so far on 144 MHz? It seems likely that it was via a combination of a marine duct from Cape Verde up as far as Morocco and via Sporadic-E from there to Italy.

The tropo prediction map from Pascal, F5LEN shows some tropo in the Mediterranean Sea so that can't be discounted either. However, there must surely been at least one Sporadic-E hop in there somewhere.

Full D4VHF log including the EA & EA8 stations shown below...