Tracking a high altitude balloon over Ireland on the 70cms band - 9th Jan 2024

 

Thanks to Robbie, EI2IP putting a post up on Facebook, I noticed that a high altitude balloon was crossing over Ireland due to the easterly winds over the country and it was transmitting on the 432-440 MHz 70cms band.

I remembered that I had managed to decode RTTY signals from a balloon over the UK a few years ago and I found it fascinating. It was always something on my 'to do list' to try again but I forgot all about it. When I checked today, that reception report was back in in July of 2018!

So there was no time like the present, I followed the links and started reading about it. 

Part 1 of 2... The high altitude with the amateur radio payload was named Flybag-2 and had been launched from Maastricht in the Netherlands. It was transmitting on two frequencies on the 70cms band with data on it's location, height and internal temperature.

The payload was transmitting using the Horus Binary (v1/v2) modulation format which is a digital signal that is way superior to the old RTTY mode.

I downloaded the software to decode the Horus Binary signals, starting to mess about with the various settings, tuned the radio to 437.600 MHz USB and listened....silence. 

The balloon had just cross over the east coast of Ireland and was heading west. I was using a homemade vertical colinear in the attic of my house which wasn't the best for listening for weak signals from a tiny transmitter 120kms away.

I also had the WSJT-X software running as well and I could make out weak traces in the waterfall. I tuned the radio down about 500 Hz to 437.5995 MHz. Eventually I could hear the signal weakly but still no decodes. Time to read the instructions.

The instructions said the audio level needed to be near -5dB. I had the volume well down and the software said it was 'good'? I tried turning the volume of the radio way up and success!

The stats show that I managed to get 20 decodes in total which is 20 more than I thought I'd get. The attic antenna is really blocked a lot in that direction so I was delighted to get anything.

Part 2 of 2... A few hours after Flybag-2, another balloon named Flybag-4FSK crossed to the south of Ireland. I had a lot more success with this one getting 71 decodes in total with my attic antenna.

The first decode was when the balloon was about 300kms away over the Bristol Channel and just below the horizon. My view to the east is pretty good and this resulted in a lot of decodes.

It was interesting to note that the signal was reasonably consistent up to about 00:24 UTC and then it dropped suddenly and the last decode was at 00:40.

This is the location of the balloon relative to my location. The balloon is slowly moving to the left (left).

This is the horizon from my location. The balloon from my point of view would have been moving slowly from roughly east to the south of me and then to the south west.

When the balloon was to the south-east, I was getting a lot of decodes as my horizon is close to 0-degrees in that direction. Once it got to 00:24 UTC, the local hill had an elevation of 1-degree. Beyond that, the signal dropped as the elevation of the hill got higher. 

After 00:40, the local hill had an elevation of about 3.5-degrees and it was now blocking the signal.

I knew my take-off in that direction was poor but it was interesting to see conformation of it.

High altitude balloon... There are generally two types of balloons. The one I heard back in 2018 was like a weather balloon, it went up to an altitude of about 20kms and then the balloon burst.

This time, the balloon reached a height of about 4kms where it levelled off. Unless the hydrogen/helium gas escapes or it hits rough weather, it should stay up for quite some time.

STEM... It also strikes me that this would make a great STEM project. Schools and colleges can't afford microsats but a low budget balloon could teach a lot about tracking, propagation, layers in the atmosphere, weather, etc. 

For more information, go to https://amateur.sondehub.org/

4853km TEP opening at 432 MHz reported from Curacao to Argentina - 5th Feb 2023

Brett, PJ2BR in Curacao in the Caribbean reports that on the 5th of February 2023 (01:18 UTC), his 432 MHz signal were heard by Javi, LU5FF in Argentina by Trans-Equatorial Propagation (TEP). The distance was 4853 kms!

This really is ground breaking news (*). It was only on the 4th of February that I put up a post about what was up to then the only 432 MHz reception report via TEP in South America and that was from 1978. I tagged PJ2BR on Twitter about the post and a few hours later, we have a second 70cms TEP report!

The Green exchange is for 144 MHz while the Yellow is for 432 MHz (*).

Proof of Concept (*)... For this TEP opening on 432 MHz, PJ2BR was using the Q65b weak signal mode. This is significant because it means that modern digital weak signal modes can be used for TEP openings at 70cms. It's not a case of there being too much doppler or spreading of the signal that only CW can be used. This would likely require a much stronger signal for a contact to be made.

For the record, here is a screen grab off the PSK Reporter website before it disappears.

Let's hope that this news will encourage more stations in the Caribbean and in South America to try to make a TEP contact on the 432 MHz.

(*) = Caveat... Someone raised the question if the reports on 432 MHz are genuine? They do after all follow some Q65 reports on 144 MHz and they wonder if it's the software generating these 70cms reports?

It's a bit like conducting a science experiment and we have one data point, not exactly the five-sigma required for a definitive conclusion. What we need are more stations in South America and the Caribbean to test the TEP path on 432 MHz. If there are no more reception reports then it raises some question mark over this new report. If there are more reports then it means this report was probably ok.

Addendum: 6th February 2023... There was another TEP 'reception report' on 432 MHz on the 6th of February 2023. This time it was from WP4KJJ in Puerto Rico to LU9FVS in Argentina.

I believe the stations involved have concerns about the software generating incorrect reports after the band has been changed.

I suspect what is required is the reception of a good old fashioned CW signal to eliminate any software issues.

5100km TEP opening on 432 MHz from Argentina to Venezuela - February 1978

While openings via TEP (Trans-Equatorial Propagation) on the 144 MHz band seem to be relatively common in South America, it's a different story on the higher frequencies.

While there have been verified TEP openings at 432 MHz in Africa in the past, any reports of TEP openings on the 70cms band seem to be extremely rare.

Back on the 13th of February 1978, YV5ZZ in Venezuela reported hearing LU3AAT in Argentina on '432.1 MHz'. The distance was approximately 5,100kms.

I'm not sure of the exact locations of either stations but Buenos Aires to Caracas is about 5,100kms and seems to be the right distance.

I found two accounts about this remarkable reception reports.

Article 1) The first one appeared in the Amateur Communications column, Electronics Today International from May 1978.

"Evening-type TEP extended to 432 MHz?

Recent record-breakng contacts on the 144 MHz band apparently supported by evening-type (or Class II) trans-equatorial propagation between Australia and Japan, Puerto Rico and South America, have been hot news in amateur circles amongst those who are keen on VHF/UHF DX.

However, no sooner was the upper frequency limit of Class II TEP extended to 144 MHz, previously established as being in the 100 MHz region, than evidence of the possible extension of this ionospheric propagation mode even higher in frequency - to 432 MHz - has come to hand.

YV5ZZ, located in Venezuala, is reported to have heard an Argentinian station, LU3AAT on 432.1 MHz in February during an opening when Argentinian stations were heard working Caribbean stations and stations in the northern countries of South America.

However, two way contact was not established, but this seems only a matter of time."

Article 2) The second one appeared in an article titled 'A Newly Discovered Mode of VHF Propagation [1978]' from the QST magazine dated October 1978.

"On February 13, 1978, YV5ZZ heard weak but identifiable signals from LU3AAT, on 432.1 MHz. Two-meter and 432 propagation far exceeds the capability of the TE mode YV5ZZ was using his satellite antenna system, which is steerable in azimuth and elevation. In the direction of LU3AAT, his horizon is obstructed by a range of mountains. The lowest elevation angle which allows for clearance of the mountain range is 8 degrees. 

On February 16, 1978, YV6ASU heard LU3AAT on 432 MHz, with his antenna at about the same angle of elevation. On yet another occasion, KV4FZ heard LU3AAT on 145.1 MHz. He reported that a peak in signal strength occurred when the antenna elevation angle was 8-10 degrees. This geometry suggests that single-hop F-layer reflection isn’t involved. The angle also seems high for the tilt associated with TE."

Analysis... In preparing this post, I did a search for the first 432 MHz contact with Trans-Equatorial Propagation (TEP) in South America and much to my surprise, I couldn't find anything. Despite the 1978 article saying that a 70cms contact would only be a 'matter of time', it looks as if it never happened and has yet to happen.

This raises the point that I have made in previous TEP related posts... Is there anyone in South America trying to make TEP contacts on 432 MHz??

I see many reports of TEP contacts at 144 MHz made by LU, PY, CX & ZP stations in South America and that's fine. But I think radio amateurs should also be experimenting to see what is possible, to try something new and to push the limits.

The chart about shows the progression of sunspot numbers since 1965. In 1978, the levels aren't that much higher than they are now in the Spring of 2023 and 1978 was also about two years before the peak of solar cycle 21.

Doppler... TEP propagation is well known for it's distortion of the signal due to some spreading. The higher the frequency, the higher the distortion.

I'm assuming that the distortion at 432 MHz will mean that modes like FT8, FT4 and Q65b cannot be used? But is that a correct assumption?

If nothing else, the use of modern weak signal modes will allow a weak signal to be seen on a screen even if it can't be decoded. A sign that a CW contact might be possible if only the signal was a bit stronger.

In conclusion... If anyone has any information about previous TEP contacts on 432 MHz from South America then  please let me know. If not, perhaps someone would like to try for the first 432 MHz TEP contact from South America?

Acknowledgement... Thanks to Carlos, LU7MC for sending on the Electronics Today International article. If your first language is Spanish and you're reading this post via Google Translate then send your information to LU7FC if it's easier.

Link...
1) For examples of TEP contacts on 2m, see my 144 MHz page.
2) For examples of other long distance contacts on 70cms, see my 432 MHz page.

Antenna upgrade for the GB3NGI 432 MHz beacon

The GB3NGI beacon transmits on 432.482 MHz on the 70cms band and it is located on the summit of Slieve Annora in County Antrim in the north-east of Ireland. The site is 500-metres above sea level and it's locator square is IO65VB.

It has as far as I know been operational since 2014 and beams to the south-east towards London.

The beacon keeper Gordon, GI6ATZ reports that the antenna system has now been updated...

GB3NGI 70cms Beacon: - The single 70cms yagi was replaced today (22nd Nov 2022) by a pair of Antenna- Amplifiers 9 ele yagis beaming NE and SE

This should improve the coverage quite significantly up to the NE and whilst in theory it should be at least a 3dB reduction in power to the SE my initial test here show a significant increase in signal strength - but then I am relatively close to the beacon!

The old antenna had suffered quite a bit of damage and I suspect the driven element assembly was full of water. 

Would appreciate signal reports with the new antenna system particularly from the NE but also from the SE to see if people notice any improvement/reduction in signal strength. 

The map above shows the location of the beacon and the new beam headings of 45 degrees (north-east) and 135 degrees (south-east). 

In the past, areas like Glasgow and Edinburgh were on the side of the old beam so the new system should result in a much stronger system.

The beacon has an RF output power of 20 watts and transmits JT65b on the even minutes and CW on the odd minutes in the following sequence: -

00:01 – 00:51 GB3NGI IO65VB in JT65b mode
00:52 – 01:00 GB3NGI IO65VB in CW
01:01 – 01:29 Plain Carrier
01:30 – 01:40 GB3NGI IO65VB in CW
01:41 – 02:00 Plain Carrier
The sequence then repeats

To decode the JT65b, tune the carrier to obtain a tone of 1500Hz with the receiver set to USB, and the dial frequency reading 432.4805. The JT65b will then be tuned in correctly.

The antennas used for the 432 MHz beacon are a pair of 9-element Antennas-Amplifiers Yagis designed and built by Goran YU1CF :- https://antennas-amplifiers.com/product/70cm-antenna/70cm-rear-mount-wideband-strong-yagi/

Additional information...

1) GB3NGI website

700km+ D-STAR contact made on the 70cms UHF band across the Caribbean - Apr 2021

I came across details of this QSO recently which I thought was interesting. While long distance contacts in the region of 700kms on the 70cms UHF band are probably not that unusual in the Caribbean, this one was of interest as it was via D-STAR, a digital voice mode.

On the 18th of April 2021, Brett PJ2BR on Curacao completed a successful contact with Jose WP4KJJ on Puerto Rico on 432 MHz using D-STAR. See video below.

It's very easy to find videos or information about D-STAR being used for working through local digital repeaters or local contacts but it's unusual to see it being used for a long distance contact on the 70cms UHF band.

When you think you’ve done it all...Opening on 70cm to Puerto Rico. @WP4KJJ and I had a short DV/Dstar QSO on 70cm!! I am ecstatic! Distance 736Km, DV. Breaks the Covid lockdown routine 😁 One for the books. pic.twitter.com/iEVKESi2Re

— Brett Ruiz (@pj2br) April 17, 2021

3000km plus contact made on 433 MHz from St.Helena to South Africa - 16th Oct 2020

On the 16th of October 2020, there was a remarkable 3000+ km contact made on the 70cms band between South Africa and St.Helena in the South Atlantic.

The contact at 433 MHz was made between Garry, ZD7GWM on St.Helena Island and Tom, ZS1TA in South Africa. The distance was approximately 3136 kms and what was even more amazing was that the contact was made on FM!

The power used for the contact was a modest 35 watts into a vertical antenna. This was a new distance record for a contact between South Africa and St.Helena on the 70cms band.

The mode of propagation was probably a marine duct as shown by this tropo forecast map from Pascal, F5LEN.

This 3000km+ tropo path between South Africa and St.Helena opens up on a reasonably regular basis. Back in November of 2018, there was an opening on 144 MHz as outlined in this previous post.

In June of 2020, the 2m path opened up again and the most recent opening on 2-metres was on the 23rd of September 2020 when ZD7GWM was worked by no fewer than five ZS stations... ZS1TA, ZS3CVB, ZS1CF, ZS3JPY and ZS1FC.

To put these remarkable contacts on 144 MHz and 433 MHz into context, the 3136 km distance is equivalent to the path across the North Atlantic between Newfoundland and Ireland.

Link...

1) Cape Town Amateur Radio Centre: ZS1TA & ZD7GWM Set New 70cm Distance Record - 16 Oct '20

New 70cms repeater in the west of Ireland to improve coverage of the Southern Ireland Repeater Network

The Southern Ireland Repeater Network is made of seven interlinked repeaters on 2-metres and 70-cms and covers the southern half of Ireland. The coverage map as of June 2020 is shown below...

There are now plans to fit a new 70-cms repeater on the summit of Mahera in Co.Clare in the west of Ireland. This is an excellent site in terms of coverage and is one of the main transmission sites used by the state broadcaster RTE for radio and TV.

An approximate coverage map of the new proposed 433 MHz repeater is shown below....

The most significant change is that it will add Galway City to the Southern Ireland Repeater Network which is a welcome development.

The eastern part of Limerick City should also be covered although Woodcock Hill will screen signals to the western part of the city.

The coverage map also suggests very good coverage of the main road from Limerick to Galway as well as the eastern part of Co.Galway and the part of the midlands.

From my understanding, the new repeater will be installed once the travel restrictions for COVID-19 are eased.

Link...
1) Southern Ireland Repeater Network

World First FT8 Moonbounce contact completed on 432 MHz...

One of the niche areas of amateur radio and perhaps one of the most difficult is trying to make contacts by bouncing radio signals off the moon. 'Moonbounce' or EME (Earth-Moon-Earth) has its proponents who squeeze every last bit of improvement out of their antennas and equipment to overcomes the huge losses involved.

On a posting on the Moon-Net, Joe Taylor K1JT said he believed that the first moonbounce contact had taken place with the FT8 digital mode.

On the 21st of May 2020, an EME contact on 432 MHz had taken place between W2HRO in New Jersey and PA2V in the Netherlands.

While the weak signal FT8 mode is hugely popular on the HF and VHF bands, modes like JT65 are more popular for EME due to its better sensitivity.

Here is the posting from K1JT....

Some here will be interested to learn that earlier (21May20) today W2HRO and PA2V easily made (as far as I know) the first EME QSO using the FT8 mode.

Paul and Peter used WSJT-X 2.2.0-rc1, a beta-release candidate for version 2.2 of the program WSJT-X. Both stations have moderate 4-yagi setups on 432. Conditions today were not particularly good: degradation around 3 dB, and the Sun only 20 degrees from the Moon.

For terrestrial use the FT8 decoder searches over the range -2.5 to +2.4s for clock offset DT between transmitting and receiving stations. When "Decode after EME delay" is checked on the WSJT-X "Settings" screen, the accessible DT range becomes -0.5 to +4.4 s. Just right for EME.

FT8 uses 8-GFSK modulation with tones separated by 6.25 Hz. At the time of this QSO the expected Doppler spread on the W2HRO - PA2V EME path was 8 Hz, which causes some additional loss of sensitivity. Nevertheless, as you'll see in screenshots posted here, the copy was solid in both directions:

Why might you want to use FT8 instead of "Old Reliable JT65" for EME QSOs? FT8 is about 4 dB less sensitive than JT65, but with 15-second T/R sequences it's four times faster and it doesn't use Deep Search.

When I was active in EME contests on 144 MHz, I was always frustrated that even with reasonably strong (for EME) signals, one's maximum JT65 QSO rate is about 12 per hour. With FT8 you can do 40 per hour, as long as workable stations are available.

What about FT8 EME on 1296 MHz? It might sometimes work, but Doppler spread will probably make standard FT8 a problem. But if there were sufficient interest, we could make an "FT8B" or "FT8C" with wider tone spacing.

Please try FT8 for EME on any of the bands 144, 432, and 1296 MHz, and let us know your results.

-- 73, Joe, K1JT

For the FT8 moonbouce contact on 432 MHz, W2HRO was running 1KW into 4 x 15 el Yagis. PA2V was running 1KW into 4 x 27 el Yagis.

Historic first Trans-Atlantic contact made on 432 MHz - Tues 7th April 2020

On Tuesday the 7th of April 2020, a remarkable contact was made with the FT8 digital mode on 432 MHz between D4VHF on the Cape Verde Islands off the coast of Africa and FG8OJ in Guadeloupe in the Caribbean.

This was the first 70cms trans-Atlantic contact without using satellites or the moon. The most likely mode of propagation was marine ducting with the signal being trapped close to the ocean.

* * * * *

Update: Saturday 11th April 2020 - D4VHF in Cape Verde and WP3ND in Puerto Rico complete a contact with FT8 on 432 MHz. This extends the trans-Atlantic distance to approx 4,367 kms. Full info further down this post.

* * * * *

(Make sure to scroll down for updates)

432 MHz world tropo record extended even further to 4,644 kms - 1st Jan 2020

On Saturday the 28th of December 2019, Ian GM3SEK in the south-west of Scotland managed to work D41CV on 432 MHz to set a new world record for tropo on the band. The distance for this FT8 contact was an amazing 4,562 kms.

Considering the fact that it was on the 70cms band and that  the south-west coast of Scotland was one of the longest sea paths to Cape Verde Islands, it seemed as this might be a long term record.

It wasn't to be however as just a few days later on Wednesday the 1st of January 2020, Nick G4KUX in the county of Durham in the north of England managed to work D41CV also on FT8 on 432 MHz to push the record out a further 80kms or so to 4,644kms.

This is the screenshot of G4KUX having an FT8 contact with D41CV on 432 MHz.

Nick, G4KUX lives in an elevated location to the west of Bishop Auckland in County Durham in the north of England. His location is about 360 metres above sea level and he has a good take off for radio in all directions.

For the record breaking contact with D41CV, Nick was using 400 watts into a UHF Log-Periodic antenna as shown in the photo below. The suprising thing about this is that the gain of the Log-Periodic would be pretty modest and is probably no better than say a 3 or 4 element Yagi.

The gain of the Log is probably at least 10dB lower that say a box of four Yagi antennas like the ones Nick has for 144 MHz.

Mode of Propagation???... Looking at the path for the previous record contact on 432 MHz from Ian, GM3SEK in the SW of Scotland to D41CV on Cape Verde Islands then we can probably speculate that the mode of propagation was via a sea duct.

For G4KUX however, the signals had to cross over some hills and mountains in Wales and the north of England. Considering there were very good tropo conditions at the time across western Europe, it seems likely that there was an elevated duct for the most northerly part of the contact and this then coupled into a sea duct further south.

Record Limit... The map below shows the new limit of the 432 MHz tropo record.

Can the record be broken? Probably. We saw in 2019 several occasions during the year when a sea duct existed between Cape Verde Islands and the British and Irish Isles. If the only mode of propagation is via sea ducting then maybe the new record will be set from the western islands of Scotland.

What we saw in the last few days at the end of 2019 and the start of 2020 was the rarer occurrence of the sea ducting happening at the same time as an extensive tropo opening with elevated ducting. This will no doubt happen again but maybe not so often.

G4KUX contacts... This is a list of some contacts G4KUX made around the same time on FT8 on 432 MHz.

G4KUX IO94BP F6DBI IN88 FT8 -08 -15 20191229 105400  20191229 105500 70CM 432.174000  0
G4KUX IO94BP F5APQ JO00 FT8 -06 +03 20191231 153200  20191231 153400 70CM 432.174000  0
G4KUX IO94BP ON4QJ JO20 FT8 -12 -09 20191231 153500  20191231 153600 70CM 432.174000  0
G4KUX IO94BP F1ISM JN09 FT8 +03 +02 20191231 155300  20191231 155400 70CM 432.174000  0
G4KUX IO94BP ON4AOI JO21 FT8 -06 -14 20191231 160200  20191231 160400 70CM 432.174000  0 
G4KUX IO94BP F6KBF JN18 FT8 -03 -17 20191231 160500  20191231 160700 70CM 432.174000  0 
G4KUX IO94BP SP7CKH JO92 FT8 -13 -19 20200101 121100  20200101 121300 70CM 432.063000  0
G4KUX IO94BP SP2JYR JO92GP FT8 -15 -10 20200101 121400  20200101 121400 70CM 432.063000  0
G4KUX IO94BP DL1TRK JO63  FT8 -20 -14 20200101 121500  20200101 121500 70CM 432.063000  0 
G4KUX IO94BP HF1J JO73  FT8 -17 -21 20200101 151400  20200101 151700 70CM 432.063000  0 
G4KUX IO94BP DL1SUZ JO53 FT8 +00 +06 20200101 151700  20200101 151800 70CM 432.063000  0 
G4KUX IO94BP PH0TV JO32 FT8 -16 -11 20200101 152000  20200101 152100 70CM 432.063000  0 
G4KUX IO94BP D41CV HK76MU FT8 -15 -20 20200101 192900  20200101 201300 70CM 432.174000  0 

As you can see, Nick was able to work into France, Belgium, Poland, Germany and the Netherlands while there was high pressure and tropo ducting about.

All in all, an amazing week or so of propagation on the VHF and UHF bands.

Links...
a) F5LEN tropo forecasts

Australian 70cms digital record extended to 2,806 kms

Early on the morning of the 5th of December 2019, there was a remarkable tropo contact between Leigh, VK2KRR and Peter, VK6KXW on 70cms across the Australian continent. The distance was 2,806 kms and crossed over the Great Australian Bight, a part of the ocean well noted for tropospheric ducting.

This was a new Australian record for a digital contact on 432 MHz as both stations were using the FT8 mode. The previous record was 2,793 kms which was set back in December of 2016.

VK6KXW was running 75 watts from an IC9700 into a single yagi. VK2KRR was also running 75 watts from an IC9700 but his antenna was a box of four yagis.

VK2KRR's box of four yagis used for the contact. Source: VK2KRR on Facebook

The time of the contact was probably also a factor as tropo ducting is often at its best very early in the morning when the atmosphere has settled down and the sun hasn't risen yet.

The current non-digital record for the 70cms band in Australia is just a bit further at 2,862 kms. This was set between VK6KXW and VK7AC on the 17th of January 2019.

While examining both of these contacts, it can be difficult to relate to the distance of 2,806 kms and just how far it is. It might be useful for stations in Europe to remember that the distance from the west coast of Ireland to Newfoundland in Canada is 3,000kms, just an extra 200 kms.

Leigh VK2KRR has a nice website with plenty of VHF info, visit https://www.vk2krr.com/

New 432 MHz station on Cape Verde Islands raises possibility of new records being set

144 & 432 MHz Yagi antennas on Cape Verde

So far in 2019, the D4C contest team on Cape Verde Islands off the west coast of Africa have made some pretty amazing contacts on 144 MHz. Using the call D41CV, they have worked across the Atlantic to the Caribbean, up to the UK, France and Ireland via marine tropo ducting and into Germany, Italy and Slovenia with a combined Sporadic-E / marine ducting mode.

Many of these contacts were well in excess of 4000 kms in distance. See links to posts HERE.

The D4C team have recently announced that they are now active on 432 MHz (70cms).

"We are now capable to be active on #70cm #432Mhz #uhf using a 16 El yagi "Pinocchio" model (wooden boom) home made. Transverter connected to @FlexRadioSystem 6600M driving a solid state PA running 100W seems working as we have worked on SSB loc IM66 for 3000 km dx #hamradio"

As the tropo prediction map from F5LEN shows below, a marine duct off the west coast of Africa seems to exist for long periods of time during the Summer and Autumn months.

This should allow D41CV on the Cape Verde Islands to work up to coastal stations in Spain and Portugal on 432 MHz, a distance of roughly 2,900 kms.

Potential for new records???

Before we look at the potential of D41CV setting new records, we should probably look first at what the current IARU Region 1 record for tropo on 432 MHz is.

Back on the 9th of July 2015, G4LOH in the south-west of England worked D44TS on 432 MHz CW. This was a sea path of roughly 4070 kms, an amazing distance for 70 cms.

This contact was as a result of the marine duct extending much further north so that it managed to get as far as England.

Just to show how good conditions were that day, here is video clip showing G4LOH hearing the D4C/B beacon on 432 MHz...



One important point here is that G4LOH worked D44TS where as D41CV is actually on a different island. As you can seen from the map below, Cape Verde is spread out over several different islands...

You'll also notice that D41CV is further south than D44TS.

If we now look at how far 4070 kms is from D41CV then we get this map...

This means that if anyone in Ireland, Wales or England managed to work D41CV on 432 MHz then it would be a new IARU Region 1 tropo record.

I would suggest that as long as there is a 432 MHz capable station active on Cape Verde Islands then this is probably a case of 'when' rather than 'if '.

Trans-Atlantic on 432 MHz???

It's hard to imagine a 70cms signal getting across the Atlantic but it's something that can't be discounted.

Earlier in June of 2019, there was a tropo duct across the Atlantic from Cape Verde to the Caribbean which lasted several days and allowed the propagation of 144 MHz signals.

If 144 MHz signals lasted for several days, was there a shorter period of time when 432 MHz signals would have propagated inside the marine duct?

If it were possible then this is what the 4070 km distance from D41CV looks like...

If a 432 MHz signal can travel 4070 kms from Cape Verde Islands to England then perhaps trans-Atlantic is not impossible?

There should be some interesting times in the months and years ahead as these possibilities are explored.

Links...
1) Archive from G4LOH's blog
2) IARU Region 1 tropo records for 432 MHz
3) F5LEN Tropo Forecast

Video : High performance 70cms transverter by G4DDK

This video from the 2018 RSGB Convention shows Sam Jewell G4DDK describing his high performance 432 MHz transverter.



Description : G4DDK will be describes a 70cm transverter that can be built from scratch, with the support of a professional PCB, or from a kit. Sam describes the latest upgrades that mean that the receive converter side of the transverter has exceptional strong signal performance together with high sensitivity. The transmit converter side features high spectral purity and the ability to frequency lock the transverter for high stability makes it perfect for both digital and analogue operation.

Note that his website states that this transverter is no longer available. The video was only put up on the RSGB YouTube site on the 6th of June 2019 which is well after when the presentation was made.

G4DDK's website

EI8JK works Japan on 70cms Moonbounce for an EI first

Working Japan on any band from Ireland is pretty good but what about doing it on 432 MHz? That's exactly what Tony EI8JK did on Monday the 10th of September 2018 when he worked Toshia JA6AHB by bouncing 70 cms signals off the moon!

The pair have been trying to make the contact for several weeks with Tony making small incremental improvements to his system to squeeze out every fraction of a dB. In the end, they managed to complete the contact using the JT65 mode on Monday morning during a 2-hour window to make it an EI-JA first on the UHF band.

In terms of equipment, JA6AHB was using 500 watts into a 7 metre dish while Tony was using 4 x 21 element yagis with a medium powered amplifier. His antenna system is shown below.

Tony lives on the scenic Sheeps Head peninsula in West Cork and no doubt the remote location with low noise background really helps on the VHF and UHF bands. With his current set-up and more improvements on the way, he hopes to work many more stations off the moon on 432 MHz.

Hearing the Mt.Leinster 70cms repeater at 135kms on a handheld

While I was updating the code plug for my TYT MD-380 dual mode handheld, I decided to add the Mt.Leinster repeater EI7MLR on 430.950 MHz. Initially, I thought it might be interesting to see if I could hear it under lift conditions. Little did I realise that I can actually hear it all the time with the half-wave whip on the handheld just sitting next to an east facing window.

Mt.Leinster is 135kms or 84 miles from my location, quite a distance for a UHF signal. I have heard the repeater before on my main rig using a home made colinear in the attic but only under lift conditions.

The signal I am getting on the handheld is under flat conditions and it's steady... about a constant 4/1. Pretty amazing considering the distance.

The profile of the path is interesting...

Right in the middle of the path is the Comeragh Mountains at about 750m above sea level (asl). I can see these mountains from my house 40 miles away on a clear day and obviously the path from Mt.Leinster at about 780m asl to the Comeraghs is line of sight as well.

It does raise some interesting points.....

1) I tried using the handheld in the attic and I seem to hear Mt.Leinster just as well in the attic as I do at the upstairs window. I would have expected that the roof tiles would have attenuated the UHF signal more.

2) I am not hearing Mt.Leinster on my main rig with the home brew colinear in the attic. I think it might be worth trying to put up another 70cms antenna in the attic? Perhaps the colinear isn't working as well as I thought.

3) In the past, I would have considered any type of mountains as a bit of a show stopper. I found out a long time ago that if the mountains are far enough away, they are less of a problem on VHF and UHF.

New 70cms repeater in Co.Tipperary

A new 70cms repeater was installed on high ground near the town of Clonmel in Co.Tipperary on Sunday the 4th of December 2016.

Here are the basic details...

Repeater Callsign : EI7HXR
Output Frequency : 430.850 MHz
Input Frequency : 438.450 MHz
CTCSS code : 103.5 Hz
Power : 25 watts
Locator : IO62EH

The repeater is highly screened from the South by the Comeragh Mountains and Slievenamon casts a large shadow to the North.

This is the coverage to the East in more detail...

This is the coverage to the West....

Note that these maps are a guide only. If you are just outside the coverage area, you may be able to still hear it if you have a good antenna up high.

This repeater has been also linked to the Southern Ireland Repeater Network.

Reception reports to Hugh, EI2HI.

Additional info...
Tipperary Amateur Radio Group
Southern Ireland Repeater Network

GB3CM heard on 70cms

25th Nov 2016...There seems to be a reasonable lift on the VHF bands today as there is a high pressure weather system over the country. I noticed it first late last night when I heard the West Tyrone repeater GB3WT in the noise on 145.775 MHz.

This morning, the Limerick repeater on 145.725 MHz which is normally S3 on my indoor antenna was up to S8 and I was able to have a QSO with  MM0RJJ and MI0ADX on it with just 5 watts.

Looking North from here this morning, I could see the inversion layer with the high pressure keeping the air trapped near the ground. It can be seen as that dark band on the horizon which is usually slightly pink/purple in colour and is in marked contrast to the clear air above....a classic sign of air trapped near the surface.

This inversion layer means good VHF conditions and it ties in with this tropo propagation map for this morning...

The biggest suprise this morning was hearing the GB3CM repeater in Wales on 70cms. It was up to s'8' at times and that is with a home made colinear antenna in the attic. The distance is about 286 kms, well in excess of the usual range for that repeater.

GB3CM
70cm (FM) UHF Repeater
94.8Hz CTCSS tone and the 'time out' is set to three and a half minutes
Operating on 433.200MHz output 434.800MHz input
Power 20w

As I don't have the 70cms rig programmed for that CTCSS, I didn't try to work through it. I'll have to dig out the manual again :o)

Additional info...
GB3CM...Website for the GB3CM repeater.

Low Power Devices on 433 MHz

At the moment, I scan the 70cms band on a pretty regular basis and every so often, the radio will stop on  433.475 and 433.525 MHz. The signal sounds like a weak digital transmission and it's only there occasionally.

I thought perhaps it was due to an out of band signal and the receiver was being overloaded. Having said that, the Alinco 605E seems like a reasonable radio and the front end doesn't seem to be wide open like some of the handhelds.

After a bit of digging, I discovered that there is an allocation for low power device on the 70cms band. It's called LPD433... https://en.wikipedia.org/wiki/LPD433

This is the frequency chart which as you can see goes from 433 to 435 MHz.

I knew that some car key fobs and remote devices were using the band but I hadn't realised it was so extensive. Perhaps that is the reason behind the mystery signals?

What I didn't know was that in Europe, this allows licence free voice communications on 70cms.

"LPD hand-held radios are authorized for license-free voice communications use in most of Europe using analog frequency modulation (FM) as part of short range device regulations, with 25 kHz channel spacing, for a total of 69 channels."...from Wikipedia.

I noticed that Amazon are selling a dual 446 / 433 MHz radio as well...

Considering how easy it is to buy a radio, I wonder will there be more unlicenced operation on the 70cms band in future?