More information about the proposed Amateur TV experiments at 29.250 MHz & 51.7 MHz

In a previous post in August of 2021, I outlined how some radio amateurs in Europe plan to experiment with digital ATV (Amateur TV) on the 10-metre band in the Summer of 2022. That post generated quite a bit of interest.

On Monday the 6th of December 2021, the BATC streamed a YouTube presentation about current Amateur TV techniques and activity as part of the RSGB Tonight at 8 series.

While the video is about 75 minutes in length, the piece I found really interesting was about the proposed ATV experiments at 29.250 MHz and 51.7 MHz. They refer to these as the 'lower ATV bands'.

Amateur TV up to now has normally been used on the UHF and microwave bands. This new development at 29 MHz and 51 MHz will potentially allow ATV signals to be sent on frequencies which will achieve much greater distances via the ionosphere - i.e Sporadic-E and F2 layer.

I find it amazing that there is the potential of sending amateur TV signals between say Europe and  North America on the 10-metre band.

 The presentation with time guides are shown below...

Video guide...
03:35: Introduction starts
05:15: G8GTZ begins his presentation
06:55: What is ATV - Amateur TeleVision / Why amateur television? / ATV is going digital

12:00: Analogue V Digital ATV / Reduced bandwidth (RB-TV) / 80 kHz RBTV

16:30: UK ATV activity and repeaters
20:45: ATV on the air - 1 The lower ATV bands

22:45: ATV on the air - 2 Low cost 5.6 GHz FM ATV with example contact

29:45: ATV on the air 3 - DATV on QO100 (Geostationary satellite)

38:20 - DATV equipment / Getting started / Ryde DATV receiver / Portsdown DATV transceiver / DATV receive system / DATV transmit system / 

57:55: Info about British Amateur Television Club (BATC)

1:01:00 Q &A session

I am told that the numbers involved are likely to be small with perhaps something like 20-30 stations taking part. Special boards are being developed at present and no doubt, these will be be got ready for the Sporadic-E season next May.

It would be very interesting if some radio amateurs in North America got interested in this project.

Links...
1) BATC website... https://batc.org.uk/

Darwin beacon heard on 28 MHz - 7th Nov 2021

Sunday 7th November 2021: Over the last two weeks or so, I have 'heard' plenty of signals from Australia on the 28 MHz band... 'heard' as in my PC decoded FT8 and WSPR signals that may well have been buried in the noise.

I was pleasantly surprised this morning when I did a scan of the beacon portion of the 10m band and came across the VK8VF beacon near Darwin in the north of Australia.

As you can see from the image above, it is on 28.268 MHz and the signal was 419 at max with me. 

There is something special about listening to a CW signal from Australia on 28 MHz and knowing that my antenna is just a simple vertical half-wave.

The map above shows some of the stations that have spotted the VK8VF 10m beacon on the DX Cluster in the last 30 days using the proper locator format.

As can be seen, the distance is in the region of 14,000kms.

28 MHz gets quieter as the Solar Flux drops - 11th Dec 2020

 

In the last few days, I noticed a noticeable drop in the level of activity on 28 MHz as the Solar Flux drops. There is still evidence of F2 propagation as can be seen from the opening to the USA and Israel as shown in the map above but this is in marked contrast to say the 26th of November 2020 when I was hearing lots of stations from the United States.

Back in December 2019, the sunspot cycle was at its minimum when the solar flux was down around 70. In October of 2020, solar cycle 25 really woke up when the solar flux began to rise reaching a peak of 116 on the 29th of November 2020.

After that, there was a gradual decline and it was back down to 83 on the 11th of December 2020. Hence the drop in radio conditions on the HF bands including 28 MHz. 

The ARRL 10-metre contest is on this weekend and conditions for it are likely to be modest at best but not as good as it would have been two weeks earlier.

It'll be interesting to see what the flux is like around say the equinox in March 2021. We'll be a few more months into the new cycle and the sun might hopefully be a bit more active.

RSGB PSC 28 MHz Propagation Study - Nov 2020

 

In this months RADCOM magazine from the Radio Society of Great Britain (RSGB), there was an interesting news article about a new propagation study on the 10-metre amateur radio band. 

The RSGB Propagation Studies Committee are interested in looking at the modes of propagation responsible for signals in the 150km to 800km range.

For example, the map below shows some of the FT8 signals I heard on the 28 MHz band on the 17th of November 2020.

The signals from the Netherlands, Germany and Denmark (1000 kms plus) are easily explained as they were via Sporadic-E propagation. As the skip distance gets shorter however, it gets harder for the signal to return from the Sporadic-E layer.

Tropospheric propagation also happens at 28 MHz but it's a lot weaker than on the higher VHF bands. On the map above, the two stations about 100kms to the north of me and the station on the west coast of Wales who was about 200kms distant are probably via tropo.

The question then arises as to what is the propagation mode for the signals from England and Scotland in the 400km to 700km range? On the day, it seemed to be too close for Sporadic-E and too far for tropo.

This wasn't unique to just this particular day. It happens pretty much most of the time. Over the Summer months for example, I seem to hear G0OYQ near Hull (579 kms) on FT8 on 28 MHz practically every day.

Are these signals due to meteor scatter? Sp-E backscatter? Aircraft scatter? Tropo? The RSGB study hopes to address this.

The news article from RadCom is shown below...

* * * * *

RSGB's Propagation Studies Committee (PSC) has launched a new study to look at the mechanism behind long-distance inter-UK 10m propagation.

The study came about after PSC chairman Steve Nichols, G0KYA noticed that he was often seeing inter-UK 10m contacts on FT8 occurring between stations that were more than 100 miles apart.

"Normally you would expect 10 metres to give contacts out to about 30-50 miles at best," Steve said, "But these contacts, which are often fleeting, were over distances of about 150 miles. I also that they often appeared in the early mornings, but disappeared as the day progressed. We've had to wait for the Sporadic-E season to end to exclude Es as a possible propagation mode."

Steve said that the likely propagation mode was tropospheric, although aircraft scatter or ionospheric scattering can't be ruled out. Either way, it warrants closer examination.

To take part in the study, just log any UK stations heard via FT8 on 10 metres in excess of 100 miles, making a note of date, time, received SNR and the location of both you and the distant station. Please also include details of your antenna and any beam heading if applicable. Steve can then compare this with weather patterns and barometric information at the time.

PSKReporter.info and DXMaps.com can also be used to track contacts online. "We'd like to encourage new amateurs to take part as the reporting isn't too onerous, but the information you supply could be invaluable," Steve said. Steve can be contacted via email to psc DOT chairman AT rsgb DOT org DOT uk

Source: RadCom Nov 2020 Page 7

Bogus FT8 spots from DS3SHI on 28 MHz

Nearly anyone in Europe transmitting on FT8 on 28 MHz in 2020 will have been spotted by DS3SHI who is supposed to be in South Korea. This is the FT8 coverage for a station in the UK on 10-metres on the 18th of August 2020.

The first impression is that the UK station is being heard by other stations around Europe and by DS3SHI in South Korea. However, that is not the case and the DS3SHI spots are bogus.

A search on Google will show that other stations have been caught out by this and they believed that their FT8 signal on 28 MHz was reaching South Korea.

So where is this bogus DS3SHI station???

There was a very good Sporadic-E opening in Europe on the 29th of April 2020 and I made a record of the FT8 reception map for DS3SHI on 28 MHz. 

Notice how there are so many European stations and there is nothing in China, South Korea or Japan? Another tell-tale sign that this station was not in South Korea and was located in Europe.

If we take a closer look at the map for Europe then you'll notice a large cluster in the east of Germany.

I've added in Yellow shading slowing the 'skip' zone which is largely free of stations with a doughnut of stations beyond that. From this, we can deduce that DS3SHI is in the southern part of east Germany.

So we can zoom in a bit further and you can see the concentration of stations. The centre of this concentration is somewhere west of the city of Chemnitz.

Over the Summer months, I have checked the FT8 map on 28 MHz for DS3SHI and I kept a record of the stations that were heard at 0dB or stronger. The approximate location of these are shown below with the three highest signal levels shown as well.

The whole area seems to be quite hilly so it may be possible to be close to DS3SHI but be quite weak if there was a hill in the way. However, it seems likely that this DS3SHI station is located near the small city of Zwickau.

As for why? Why is someone in Germany using a callsign (DS3SHI) and locator (PM48si) for South Korea? Is it someone using an online SDR receiver? Is DS3SHI even a real call sign? 

The FT8 spots on 28 MHz that this person generates serve no useful purpose and just misleads people. As far as I can tell, this person is only listening on 28 MHz and is not transmitting.

Hopefully if people search Google for the DS3SHI call sign in future, they will find this blog post and discover that the FT8 reports from DS3SHI are bogus.

Update - 25th Aug 2020: Just after this post appeared, it was verified that the spots from DS3SHI were coming from an IP address in Germany. All spots from DS3DHI have now been blocked from the PSK Reporter site.

Illegal Fishing Buoy on the 28 MHz WSPR Frequency

Back in June of 2018, I had a post up about how I had noticed an illegal fishing buoy on the FT8 frequency of 28.074 MHz. Today, I noticed one on the WSPR frequency of 28.1246 MHz.

Truth be told, these things are all over the bottom of the 10-metre band and it's not hard to stumble across them.

The image above shows the fishing buoy on the waterfall display of the WSJT-X programme. It turns on as a carrier which rapidly drifts upwards, settles down and finally gives an ID in morse. The whole transmission lasts for about 10 seconds.

I was listening one day on 28.200 MHz for the International Beacon Project cluster of beacons and sure enough, there was one there as well.

From what I understand, they are used to mark the position of fishing nets at sea and are almost impossible to police or regulate.

First trans-Atlantic QRSS signal of 2020 on 28 MHz - Mon 25th May 2020

Monday 25th May 2020. For a change, I left the radio on the WSPR frequency of 28.1246 MHz this morning to see what could I hear. At the time, there seemed to be some unusual propagation in that I was hearing Iceland to the north-west.

Then I got two decodes of the WSPR signal from Vernon, VE1VDM in Nova Scotia, Canada!

Timestamp          Call MHz SNR Drift Grid Pwr Reporter RGrid km az
 2020-05-25 11:30 VE1VDM 28.126118  -24 -2 FN85ij 2 EI7GL  IO51tu  4001 59 
 2020-05-25 11:20 VE1VDM 28.126118 -22 -1 FN85ij 2 EI7GL  IO51tu 4001 59 

While 28.0008 MHz is the usual QRSS frequency on 10 metres, some stations transmit right next to the WSPR frequency of 28.1246 MHz so that receive stations can listen for both WSPR and QRSS signals without changing frequency.

It just so happened that I had the SpectrumLab audio analyzer programme running as I often use it to check the frequency of beacons on 28 MHz. When I looked, I could see the QRSS signal (very slow morse) from VE1VDM but it was slightly drawn out as I was using the 'QRSS 1' option. I switched to QRSS 3 and the screen grab is shown above.

I suspect the signal from Vernon may have been at its best when I was hearing the WSPR signals. I'd guess that the QRSS signal used to generate the plot shown above is certainly not stronger than the -22dB or -24dB WSPR signal.

VE1VDM was using a QRP Labs U3S and 5 watt PA combo sending 4 watts into a full size Windom hung as an inverted V at about 30' AGL at apex, I was using a vertical half-wave for 28 MHz about 4 metres above ground level.

Mode of Propagation???... How did this QRSS signal cross the North Atlantic?

A few days ago, VE1VDM had been heard on WSPR in Luxembourg and Germany, a distance of about 5000 kms. This was most probably triple hop Sporadic-E... i.e. 1700kms x 3 hops. The second hop signal that day was probably landing somewhere in the ocean about 600kms to the west of Ireland.

For the trans-Atlantic opening today, I think I was hearing VE1VDM via double hop Sporadic-E i.e. 2 x 2000km hops. It's likely that the signal may have reached only Ireland and the western part of the UK as that's close to the limit for two hops on 28 MHz.

For more information on QRSS activities, there is an active group HERE

276km Reception of Beacon in Wales on 28 MHz

During a Sporadic-E opening on the 20th of May 2020, I came across GW7HDS/B beacon in the south of Wales on 28.2215 MHz.

This is a very unusual beacon for me as it is 276 kms away and would normally be too far away for tropo and too close for Sporadic-E. When I heard it first, I thought it must have been some exceptionally short Sporadic-E.

I noticed however that the signal was pretty constant. After a few hours, it was still there and didn't behave like Sporadic-E.

By accident, I also noticed that the BBC Radio 4 signal on 104.9 MHz from Haverfordwest on the west coast of Wales was a big signal here. Even though it is some 140 kms distant, I was able to listen to it using just my mobile phone and the headset lead as an antenna.

Later in the evening, the GW7HDS beacon had gone and coincidentally, so had the signal on 104.9 MHz.

I often hear stations on the west coast of Wales on 10m on FT8 but it's hard to read any meaning into signals that are there in bursts and are infrequent. Are they tropo? Aircraft scatter? Back scatter?

Tropo conditions on the higher VHF bands like 2-metres and 70-cms are pretty common but not so much on the lower bands like 10-metres. Was it a tropo signal on 28 MHz? Possibly but I still suspect it might have been backscatter for Sporadic-E.

With the beacon frequency stored safely in a memory channel on the radio, I'll have to look out for it again in the future.

Japan & USA heard on 28 MHz - Fri 15th May 2020

Friday 15th May 2020. As we reach the middle of May, the multi-hop Sporadic-E paths on 28 MHz are really starting to open up.

Japan... The big suprise for me was the reception of JJ1RDX in Japan. I checked the spot and it's genuine. At 9,767 kms, this probably required in the region of 5 or 6 Sp-E hops to reach here.

USA... K9RX in South Carolina was heard at a distance of just over 6,000 kms. 

What is significant here is not so much the distance but the fact the opening was East-West. North-South openings are not so special as one hop to the south from N Europe and you're into an area where F2 and TEP is possible. It's the East-West openings that are special.

Sp-E... From just a European perspective, the opening to Europe wasn't great. Even though there are lots of dots on the map, the band was open for hours to just Spain and Portugal and no where else. I did several scans and heard just three CW beacons all day.

These are the FT8 stations heard over 2,500 kms...

Italian QRSS signals heard on 28 MHz - 11th May 2020

Conditions on 28 MHz on Monday the 11th of May 2020 were very good with some very strong FT8 and SSB signals heard on the band.

While the skip distance didn't get short enough for me to hear some of the UK QRSS stations (<600kms), I did hear two Italian QRSS beacons on 28.3216 MHz CW at about 22:00 UTC. See photo.

From the information that I have, I3GNQ/B runs 200mW into a vertical and uses the QRSS code 'GB'. IZ1KXQ/B runs 100mW into an inverted-V and uses the QRSS code 'SP'. As the image shows, there are about 143 Hz apart.

From what I can tell, these are the only two Italian QRSS signals on the 10m band.

I3GNQ beacon - 200 milliwatts (2N1711 transistor) into a 5/8 vertical antenna

Close up of the I3GNQ beacon

Thanks to Jack I3GNQ for the photo.

I3GNQ also mentions that this low power beacon will be turned off in July of 2020 as the property where the beacon is located has been sold.

Links...

1) QRSS Knights on Groups dot io

Illegal fishery buoy on the 28 MHz FT8 frequency

Anyone that uses 28 MHz on a regular basis will have heard illegal driftnet fishing buoys which give out a short carrier followed by an id in morse.

Over the last few days, I have heard one on the FT8 frequency of 28.074 MHz (USB). It is shown below in the waterfall plot as a short narrow carrier in amongst all the FT8 signals.

It is a solid carrier for about 10 seconds and is then followed by the letters E H in morse code. (Something like a 10 second dah followed by dit.....dit dit dit dit ). It transmits every 2m 30s.

I only noticed it in the last few days so I presume that it was only recently switched on.

As for the location, these are the FT8 signals I was hearing at the time....

I would guess either the western Med or out in the Atlantic but it's very difficult to know.

Links...
1) IARU Region 1 page on 28 MHz driftnet buoys

FT8 on 28 MHz... Tues 15th May 2018

There were plenty of FT8 signals on the 10 metre band on Tuesday the 15th of May 2018 although noticeably fewer than previous days.

This is what was heard from about 8am till about 7pm....

That pretty much represents what could have been heard anyway as the band was hardly open at 8am and it closed in the late afternoon. Other than some signals from South America, the only DX as such was a station in Western Sahara.

I think the spot from Liberia was bogus one as the callsign looked wrong. Almost as if something wasn't decoded properly.

There were fewer European stations as well with nothing coming from Scandinavia.

Overall, I heard 187 stations in 28 countries on Tues 15th of May.

I'll continue until I have a weeks worth of data and review it then.

FT8 on 28 MHz... Sun 13th May 2018

Another day with loads of activity on FT8 on 28 MHz. The map below shows what was heard in the 24 hours of the 13th of May 2018...

The 10 metre band opened in the morning and closed around 22:00 UTC. There was one short spell in the early afternoon where the band closed completely when there was no Sporadic-E propagation.

As can be seen from the map, there was plenty of signals from South America but not a whole lot going East-West. I suspect there would be a lot more spots from Africa if only there were stations active there.

The map below shows the activity from Europe. The most consistent signals all day were from the south to Spain and Portugal.

The Solar Flux was 69 today which is pretty low. Overall, I heard 445 different stations in 49 countries over the last 24 hours.

FT8 on 28 MHz... Fri 11th May 2018

Another interesting day listening to FT8 digital signals on the 28 MHz band. This is what I heard during the 24 hour period...

Signals from stations in China and Kazakhstan were heard at about 4:45 UTC which was dawn at my location. F2? Sp-E?

Several from South America including the Falkland Islands.

Cape Verde, Maderia and the Canaries in the Atlantic.

TR8CA in Gabon and the maritime mobile station off the coast of Angola again.

Again, plenty from Europe....

It still suprises me how many stations in the UK I can hear. They should normally be too close except for when the Sporadic-E conditions are pretty intense. As for today??? Direct Sporadic-E? Backscatter? Meteor or Aircraft scatter?

Interesting little group of stations out in Eastern Ukraine and in Russia. The band was also open to Germany at the same time so the eastern european signals were probably double hop Sporadic-E.

In total, I heard 387 different stations in 44 countries. Not as busy as the 10th of May but pretty good all the same.

FT8 on 28 MHz... Thurs 10th May 2018

I left the radio on 28 MHz all day today listening on the FT8 frequency. From what I could hear, the band seemed to be open from early morning until after midnight.

This is what was heard during the 24 hours of Thursday the 10th of May 2018...

Considering the solar flux levels are down at 70, it was pretty amazing what could be heard on 10 metres. Some of the notable signals heard were....

Five stations in Indonesia.
One in China as well as several in Kazakhstan and Uzbekistan.
One in South Africa and a maritime mobile station off the coast of Angola.
Brazil, Argentina and Chile in South America.
Two in Puerto Rico, two in the Dominican Republic and one in Dominica in the Caribeean.
And of course, plenty in Europe...

According to the PSK reporter website, I heard 865 stations in 59 countries in the last 24 hours.

It was interesting that because I was the only station in Ireland for most of the day, I was sometimes the only person hearing a distant station because of my westerly location.

At one stage, I had a look at the WSPR website. At that instant, there were 70 stations monitoring the 10 metre band on WSPR then where as there were 302 on FT8 at the same time. That's the thing that impresses me most about FT8, it seems to have the critical mass of people using it for it to be useful. I have noticed that on WSPR in the past, the band was obviously open to certain areas but there just wasn't anyone on from those locations.

Another advantage of just listening on this mode is that I don't actually have to be there. I was away from the radio for most of the day and the PC was doing all the work of decoding the signals and uploading the spots to the PSK reporter website.

This was only my second day listening on FT8 and I'd imagine I'll be using it now for the Summer for the Sporadic-E season.

FT8 on 28 MHz... Wed 9th May 2018

This morning, I noticed that the 28 MHz band was open but I couldn't hear one single CW beacon on the band. After hearing about the popularity of the latest digital mode FT8, I downloaded it and was listening on the band within an hour.

This is what I heard today on 28 MHz in Europe on FT8...

Most are about the right distance for Sporadic-E but there were a few suprises. The stations in the UK and Brittany were about the 500km mark...a bit short for Sporadic-E but not unknown. The ones in Bulgaria, Turkey and Russia are too long for one hop Sporadic and were probably multi-hop.

Outside of Europe, I heard these....

Like yesterday, I suspect that some Sporadic-E was helping out for the first hop to get down to lower latitudes where F2 propagation was possible. Still though, some interesting signals were heard. The one is Angola was a UW5EJX maritime mobile off the African coast.

In the 12 or so hours from 11:00 UTC to 22:00 UTC, I heard 104 different stations spread across 31 countries.

After just one day listening on the mode, I am very impressed at what I heard with a simple vertical antenna.

Links...
1) WSJT-X software suite
2) PSK reporter

F2 Opening on 28 MHz to Africa on Wed 1st March 2017

With the Solar Flux Index down around 75, the 10 metre band is more or less dead every day at the moment. It was a bit of a suprise on the 1st of March 2017 when signals from Africa appeared on the band.

The first signal I heard was TR8CA in Gabon on 28 MHz SSB and later on 29 MHz FM. This was followed soon after by S01WS in the Western Sahara who I worked on cw.

I could hear these stations working plenty of Europeans and Americans so it was obviously a good opening. When I saw TR8CA being spotted by LA and SM stations in Norway and Sweden, then I knew something really unusual was happening. I suspected some sort of pre-auroral enhancement and the RSGB news a few days later confirmed this...

We were pleased to get the HF propagation prediction pretty much spot on last week. While Monday and Tuesday were reasonably settled, Wednesday saw the effects of solar material from a large coronal hole as it hit the Earth. The K-index leapt to five around lunchtime and there were reports of HF openings up to 10 metres. This was probably a pre-auroral enhancement, but it didn’t last too long.

This is what the K index looked like just before and after the event...

As you can see, nice and low early on the 1st of March and then the K index climbs to 7.

As is common with these type of events, the HF bands were very poor in the following days with 18 MHz just about open. 21 MHz and 28 MHz were dead.

The map below shows TR8CA and S01WS in relation to my location.

S01WS in the Western Sahara was about 2,900kms and the ideal distance for one hop F2 propagation on 28 MHz. TR8CA at about 6000kms was probably 2 x F2 layer hops so it was an interesting one to hear.

The thing about the 10 metre band is that you can never be too sure when it will open. When the Solar Flux Index is down around 70-80, it should be closed but then events like this allow the band to open, especially on North-South paths.

Slim Jim Vertical Half-Wave for 27 MHz & 28 MHz

Another one from an old magazine article. This design is for a basic folded half-wave vertical for the 11m CB band on 27MHz but it can also be adapted very easily for 28Mhz or 29Mhz. For 10m operation, try reducing the half wave section to 5.10 metres and the quarter wave section to 2.53 metres.

It really is a case of experimenting and see how you get on. It's likely the biggest challenge will be the mechanical construction rather than adjusting the VSWR.

One particular advantage of this antenna is that the quarter wave tuning section effectively puts the radiating element higher above ground level. This fact alone can have a significant effect on the performance of the antenna as it begins to get clear of buildings, electricity wires and other clutter near ground level.

A lot of novice CBer's get fixated on 'advertised gain' and different types of antennas whereas they should be concentrating on getting a decent antenna up as high as possible.

While the Slim Jim won't be as good as say a Yagi beam up on a tower, it should still perform pretty well.

Opening to the Indian Ocean on 28 MHz...Wed 14th Dec 2016

Wednesday the 24th of December was another one of those days where the 28 MHz band seemed completely dead but early in the morning, I received 3 separate transmissions on WSPR from FR1GZ on Reunion Island in the Indian Ocean.

It's almost as if the North-South path is there on a lot of days but there just aren't any stations there to exploit it.

The Solar flux is down around 72 and the K index is a 1.

Three Eight Wave Ground Plane Antenna for 10 Metres

Over the years, I have collected many old magazine articles and it seems to be a waste to have them buried away in a folder. This one is for a 3/8 wave ground plane antenna for 28 MHz and hopefully it might encourage someone to experiment and build one.

The principle is pretty easy. A normal dipole in free space normally has a 72 Ohm feed point impedance. A quarter wave ground plane is half this...about 36 Ohms.

By extending the antenna from a quarter wave to a three-eight wave, the maximum current point moves from the base to further up the radiating element. This has the effect of lowering the angle of radiation which is a plus.

The longer three-eight wave antenna now has a reactive feed point (inductive) as it's too long. This is tuned out with a series capacitor and it should be able to get close to 50 Ohms.

This antenna would suit someone who can only put up a quarter wave ground plane for 10 metres and wants better performance.

The article from the March 1983 edition of Short Wave Magazine is shown below...