As part of a challenge for 2024, I've decided to see how many QRSS signals I could capture on the 28 MHz band during the year.
QRSS are very slow morse code transmissions where the dots and dashes are several seconds long and the signals are decoded by looking at a waterfall display on a screen rather than listening to the signal.
The QRSS signals are usually just below the WSPR signals on the amateur radio bands. This means it's possible to have your PC decoding WSPR signals up around 1500 Hz while you look at the QRSS signals about 500 Hz or so lower in the audio spectrum at the same time.
2024 #8 - OH5KUY... The 8th QRSS signal that I managed to capture this year was Ari, OH5KUY in Finland. Ari reports that he is running 1.5-watts into a C610 vertical antenna. His locator square is KP41DB.
The distance is from OH5KUY to my location is about 2437kms, an ideal distance for F2 layer propagation when the 28 MHz opens up to these northern latitudes.
Ari's signal was actually very strong for a QRSS signal and I had to adjust the volume settings on the radio because it was too strong compared to the rest. Most QRSS signals are buried in the noise and you get to see them only on a screen. Ari's signal by contrast was up to S4 here and it was a loud clear signal.
This is the signal in more detail. As you can see, something happened at Ari's location at about 13:52 to cause a slight rise in frequency. It's only about 4Hz but it can be seen.
That's the beauty of QRSS, you can actually 'see' the signal. You can see the frequency drift , you can see how the strength of the signal changes over time and you can see any unusual propagation effects.
With digital modes like FT8 and WSPR, you either get a decode or you didn't and if there isn't a decode, you're often not sure why. With SSB or CW, you're listening to an audio signal but it's what's happening here and now. You're missing those visual clues of QRSS which add so much more information.
The one that got away... It looks as if there was Sporadic-E on the band as well on the 17th. TF3HZ in Iceland popped out of the noise and I was all ready to get a nice screengrab but I lost it when I changed some settings on the SpectrumLab software. Lesson... screengrab first, adjustments later. Another day...
In summary... That brings the QRSS tally so far for 2024 up to 8-callsigns & 5 DXCC.
1) 08 Jan 2024: VE1VDM - DXCC #1 2) 10 Jan 2024: VA1VM 3) 15th Jan 2024: G0MBA - DXCC #2 4) 15th Jan 2024: G0PKT 5) 15th Jan 2024: AE0V - DXCC #3 6) 16th Jan 2024: RD4HU - DXCC #4 7) 16th Jan 2024: W1BW
As part of a challenge for 2024, I've decided to see how many QRSS signals I could capture on the 28 MHz band during the year.
QRSS are very slow morse code transmissions where the dots and dashes are several seconds long and the signals are decoded by looking at a waterfall display on a screen rather than listening to the signal.
The QRSS signals are usually just below the WSPR signals on the amateur radio bands. This means it's possible to have your PC decoding WSPR signals up around 1500 Hz while you look at the QRSS signals about 500 Hz or so lower in the audio spectrum at the same time.
2024 #6 - RD4HU... Most QRSS signals take the form of very slow morse code transmissions but sometimes, other modes are used. The screen capture above shows the slow-Hellschreiber mode which is more often referred to as "slow Hell".
RD4HU is located in the city of Samara on the Volga River in European Russia and was using 5-watts as far as I know. His signal was strong as can be seen by the clear trace.
The distance to my location on the south coast of Ireland is about 3855 kms which is ideal for one F2 layer hop, hence the strong signal.
2024 #7 - W1BW... Another method of sending a signal is as a symbol or character. This is where some degree of artistic flair comes into play.
Bruce, W1BW in Boston has a flying 'W' that he uses for QRSS. W1BW is running 200mW from a Hermes Lite 2 and the antenna is a random dipole about 25m long on the rooftop of a condominium building in the city of Boston, about 25m AGL and 2m above roof level..
W1BW is located just over 4700kms from my location and the mode of propagation was probably two hops from the F2 layer of the ionosphere.
In summary... That brings the QRSS tally so far for 2024 up to 7-callsigns & 4 DXCC.
1) 08 Jan 2024: VE1VDM - DXCC #1 2) 10 Jan 2024: VA1VM 3) 15th Jan 2024: G0MBA - DXCC #2
As part of a challenge for 2024, I've decided to see how many QRSS signals I could capture on the 28 MHz band during the year.
QRSS are very slow morse code transmissions where the dots and dashes are several seconds long and the signals are decoded by looking at a waterfall display on a screen rather than listening to the signal.
The QRSS signals are usually just below the WSPR signals on the amateur radio bands. This means it's possible to have your PC decoding WSPR signals up around 1500 Hz while you look at the QRSS signals about 500 Hz or so lower in the audio spectrum at the same time.
2024 #3 & #4 - G0MBA & G0PKT... The QRSS signals shown above were captured at about 10:40 UTC and it shows the QRSS trace from G0MBA and G0PKT who are 650kms to the east of my location in Essex, England. From what I know, I think both are running 0.2-watts into vertical antennas.
You'll notice that the signals have a slight 'fuzz' as opposed to a clean tone. I hear/see these two stations practically every day and I think the signals are F2 layer backscatter. If I was to try again during the Sporadic-E season during the summer, both signals would be nice and clean.
At 650kms, both signals from G0MBA & G0PKT are way too far for ground wave and too close for normal F2. The signals are probably being propagated off the F2 layer, being reflected in some distant region and then returning to my location.
2024 #5 - AE0V...In the afternoon, I got a capture of the QRSS signal of AE0V in Minnesota (EN34FU) in the USA who is about 6,000kms from my location.
Ned, AE0V reports using a solar powered transmitter with no battery storage running 100mW into a 1/4 wave stainless whip about 8m above the ground.
The signal from the USA is easily explained as it's via multi-hop F2 layer propagation.
In summary... That brings the QRSS tally so far for 2024 up to 5-callsigns & 3 DXCC.
1) 08 Jan 2024: VE1VDM - DXCC #1 2) 10 Jan 2024: VA1VM 3) 15th Jan 2024: G0MBA - DXCC #2
The highest HF band used for broadcasting is the 11-metre band which runs from 25.6 MHz to 26.1 MHz. It's an unusual band and many of the smaller receivers don't even go that high in frequency. Even in the golden days of short-wave broadcasting, very few stations used it.
As we're near the peak of the sunspot cycle, I went looking to see what exactly is on the band and who is using it.
As far as I know, there are three transmitters using the band and these are shown above.
This is the schedule for January to March 2024....
Frequency (kHz) - Station - Times in UTC - Transmitter
25800 kHz - World Music Radio - 24-hours - Denmark - 0.060 kilowatts
25900 kHz - BBC World Service (French) - 12:00 to 12:30 - Madagascar - 250 kilowatts
25900 kHz - BBC World Service (English) - 16:00 to 18:00 - England - 125 kilowatts
Report & information...
1)World Music Radio transmits from Aarhus in Denmark with just 60-watts on 25.8 MHz. In terms of broadcasting on AM, this would be considered very low power.
The antenna is likely to be very modest but it does seem to be on top of a very high tower as shown above.
Back in the summer of 2021, I had a post on the blog about how I had heard it via Sporadic-E propagation. I tried listening for it today at around midday on the 11th of January 2024 and I could make out a weak carrier on CW.
It was way too weak to resolve on AM today but it's highly likely that it was the World Music Radio transmitter I was receiving. I did notice the carrier was inclined to drift a bit (~5-10 Hz) but that doesn't make any difference for an AM signal.
2) The BBC World Service transmits to Africa in French on 25.9 MHz from a 250-kilowatt transmitter at Talata-volonondry on the island of Madagascar. Considering the transmission only lasted 30 minutes, I presume this is a commercial site where broadcasters rent time on it.
The signal was S9 when I listened to it and I think anyone in Europe should hear it as it's a north-south path.
3) The final transmitter was the BBC World Service in English which broadcasts to Central and West Africa on 25.9 MHz. The 125-kilowatt transmitter is located in Woofferton in the east of England and this transmission lasted two hours.
This transmitter is 390 kms from my location on the south coast of Ireland so I am well inside what is considered to be the F2-layer skip zone. Just after 16:00 UTC, the signal was about S4 on CW. On AM, I knew someone was speaking English but it was very difficult to hear.
Propagation Modes???... The signal from Madagascar is easy enough, it's multi-hop F2 with possibly some TEP in there as well.
As for the 60-watt signal from Denmark? At 1300kms, it was probably a bit too close for F2 layer. Maybe F2 layer backscatter or ionoscatter?
For the signal from England, it was stronger at 16:00 as compared to 18:00 UTC so it wasn't ground wave or some sort of tropo. The ionosphere was certainly involved. Again, either F2-layer backscatter or forward ionoscatter.
In conclusion... It was interesting to see some activity on the 11-metre broadcast band. I suspect though it may be on borrowed time. Two broadcasters seem to be using it for the peak of this sunspot cycle but will anyone be using it at the peak of the next one in eleven years time?
As part of a challenge for 2024, I've decided to see how many QRSS signals I could capture on the 28 MHz band during the year.
QRSS are very slow morse code transmissions where the dots and dashes are several seconds long and the signals are decoded by looking at a waterfall display on a screen rather than listening to the signal.
The QRSS signals are usually just below the WSPR signals on the amateur radio bands. This means it's possible to have your PC decoding WSPR signals up around 1500 Hz while you look at the QRSS signals about 500 Hz or so lower in the audio spectrum at the same time.
2024 #2 - VA1VM... The first signal I captured in 2024 was from Vernon, VE1VDM in Nova Scotia, Canada back on the 8th of January. This is outlined in this previous post.
Conditions on the 28 MHz band were better on the 10th of January and the 'VDM' QRSS signal was in again but stronger as can be seen above. For this beacon, Vernon was using a QrpLabs U3S with low pass-filter into a QrpLabs power amplifier delivering 1-watt on 10m. The antenna was ground mounted Hustler 6BTV vertical.
In the last 24-hours, Vernon has put a second QRSS transmitter on the air with the callsign VA1VM. You can see this as a weaker signal in the image above.
The VA1VM signal is from a 150 milliwatt transmitter into a Hustler 10m 1/4 wave resonator mounted on a 1.37-metre long Hustler mast extender. It really is amazing that a 0.15 watt signal can make it across the Atlantic.
Both beacons are located in the town of Truro in Nova Scotia and are just a few kms apart. The antenna on my side was a simple CB type half-wave vertical.
The map above shows the location of the transmitter and receiver. The distance is about 4000kms which is ideal for 1-hop of F2 layer propagation.
Even though it's the same person, it's a second QRSS signal. That brings the QRSS tally so far for 2024 up to 2-callsigns & 1 DXCC.
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.
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.
As part of a challenge for 2024, I've decided to see how many QRSS signals I could capture on the 28 MHz band during the year.
QRSS are very slow morse code transmissions where the dots and dashes are several seconds long and the signals are decoded by looking at a waterfall display on a screen rather than listening to the signal.
The QRSS signals are usually just below the WSPR signals on the amateur radio bands. This means it's possible to have your PC decoding WSPR signals up around 1500 Hz while you look at the QRSS signals about 500 Hz or so lower in the audio spectrum at the same time.
2024 #1 - VE1VDM... The first signal I captured in 2024 was from Vernon, VE1VDM in Nova Scotia, Canada.
Vernon was using a QrpLabs U3S with low pass-filter into a QrpLabs power amplifier delivering 1-watt on 10m. The antenna was ground mounted Hustler 6BTV vertical.
The antenna on my side was a simple CB type half-wave vertical.
The map above shows the location of the transmitter and receiver. The distance is about 4000kms which is ideal for 1-hop of F2 layer propagation.
So that's the QRSS tally so far for 2024... 1-callsign & 1 DXCC.
Back in December, I carried out an experiment to find and record the peak of the Geminids meteor shower by listening to the GB3MBA 50 MHz beacon which is 500kms from my location. See post HERE
On the afternoon of 4th of January 2024, there was the peak of the Quadrantids meteor shower which tends to be very narrow but intense. This time, I just took some screenshots of the meteor reflections.
Introduction... Back in 2022, a new radio beacon called GB3MBA was put on air on the 50 MHz band and its primary purpose was carrying out meteor scatter experiments. Located near the town of Mansfield in the centre of England, the beacon runs 75-watts into a small Moxon antenna which beams straight up.
Unlike most amateur radio beacons, this one is basically a carrier that is on nearly all of the time which is exactly what is needed for meteor scatter experiments. The main coverage area is the UK itself but as I'm 502 kms from the beacon, I'm close enough for it to be of use.
For the Quadrantids meteor shower, I was using a Yaesu FT817 on USB as a receiver and the antenna was a 2-element Yagi in the attic of my house. The antenna was beaming about 120 degrees which is about 45 degrees off the beam heading for the beacon (The choice of beam heading is determined by the space in the attic and I wasn't trying to beam away from the beacon).
Quadrantids screen shots...
The image above shows the composite collection of seven different screenshots. As can be seen, there was plenty of evidence of pings and bursts from the GB3MBA beacon.
The images on the blog are quite small and a link to a larger version of the image is on Facebook HERE.
I'll use the more detailed example above to explain what you are looking at. The time is moving from right to left and you will notice the 30-second timestamps. As my receiver isn't GPS locked, I'm probably around 5 Hz off frequency which is ok.
If I was hearing the beacon directly, it would show up as a solid yellow line going across the centre of the screen. Instead, you are looking at the signal reflecting / refracting off the trail of electrons left behind by the meteor as it burnt up. As these electrons are in motion in different layers of the upper atmosphere, there is some doppler shift on the signal.
In the example above, the 50 MHz signal lasted for about 90-seconds.
The signal on the far right of the image above is one of my favourites. This is called an 'epsilon' echo as it twirls around. What causes such a complex pattern as opposed to the other 'smudges'?
Thanks to short wave listener Bill Smith, W1-7897 for sending on his reception report for December 2023.
Bill who is located near Douglas in Massachusetts in the United States is using a Yaesu FT-847 as a receiver on the 40 MHz (8m) band with a 5-element beam for the 50 MHz band.
Bill reports slim pickings on the 40 MHz band of late but did manage to log Jack, LX5JX in Luxembourg on the 27th of December 2023 calling CQ from 13:34 to 13:39 UTC. Bill reports that the FT8 signal strength was from -9dB to -17dB on 40.680 MHz.
As can be seen from the map above, the path was about 5,800 kms and was most likely two F2 layer hops.
Before we get too far into 2024, I had a quick look back at the traffic to the blog in 2023. As can be seen from the chart above, the average number of pageviews in 2023 was about 20,000 per month.
I should note that pageviews doesn't mean the actual number of people. If you were to visit the site every day then you'd generate 365 pageviews for the year. I'd guess very few people visit every day and 20,000 is still a significant amount of traffic for a blog about amateur radio and radio technology in general.
The volume of traffic during the year fluctuated quite a lot during the year and that is reflected in the number of times I posted...
2023 (110) December (14) November (12) October (5) September (1) June (1) May (3) April (3) March (15) February (23) January (33)
I put up posts nearly every day back in January and February, once every two days in March and then I hardly posted anything for months. This had an obvious impact on the level of traffic to the blog.
When I post every few days, the blog gets about 600-800 pageviews per day. If I don't post anything then the daily traffic drops to about 200-300 pageviews per day.
The thing is that the blog is just a hobby for me. It's not a job and if the site gets a lot of hits then great but it's not my reason for posting. I generally blog about things I find of interest regardless of how popular it might be to others.
Each post could take about two hours to prepare and sometimes longer. If I don't find the subject of interest then I don't bother.
How it works... The process for generating a blog post works like this...
I see something that is of interest to me. I can see that the news item isn't reaching a large audience / should get more publicity / wasn't fully explained.
I then generate a blog post about the news item of interest and include maps, diagrams and an explanation if necessary.
The blog post can take around 2 hours to generate, sometimes longer.
Links to the blog post then go out on social media so more people can notice it.
Missing posts... As for the lack of posts from April to October...
I get distracted! 😂 I'm off doing other things with my time.
Staying in the loop of the usual news sources takes time and it can take a while to even get back into the routine again.
Traffic Sources... I guess it would be natural to assume that most of the traffic to the site comes from Ireland but that's not the case. These are the largest countries by traffic by country during the year...
United States 63.1K
United Kingdom 13.9K
Germany 13K
Netherlands 10.6K
Ireland 8.37K
Italy 6.36K
France 4.75K
Canada 2.37K
The chart above shows the number of posts per year on the blog. 2022 and 2023 were pretty modest with about 110 posts each for the year. Still though, the traffic for 2023 seems pretty healthy compared to previous years despite the lower number of posts.
Social Media... As for the social media channels...
The EI7GL Facebook page now has 551 followers.
The Twitter / X account has 1429 followers.
The Instagram account has 310 followers.
In conclusion... It would be easy to make a New Year's resolution and say I'll post more this year but I know it will be harder once the evenings get longer. I have a few plans for the blog which I'll cover in a separate post which might change things a bit. I know whatever I do, I'll have to find it interesting to keep my focus.
The American Radio Relay League (ARRL) is the national society for radio amateurs in the USA and is one of the largest if not the largest such organisation in the world. They also produce the QST magazine which is one of the largest amateur radio magazines in the world.
Back in July of 2023, they announced that they would be increasing their membership fees by between 20% to 71% at the start of 2024. In this post, I'll look at some of the changes.
Membership - US Members...
US members of the ARRL paid $49 per annum up to and including 2023. For that fee, they were able to receive the QST magazine by standard post. As of the 1st of January 2024, that membership fee now increases by 20% to $59 and for this, they will have access to only the online digital version of QST.
If US members wish to keep receiving QST by standard mail then they will have to pay $84, a 71% increase on their old subscription of $49.
US members who were getting QST by first class mail will see their subscription increase by 37.5% from $96 to $132.
Three year membership fees follow much the same pattern... 3-year membership with QST mailed out goes from $140 to $174 for membership and digital QST only, a jump of 24%. To keep getting QST by mail for 3-years, members will have to pay $249 instead of $140, a 71% jump.
Membership - International Members... As non-US members, it's probably fair to say that most international members have joined to get access to the QST magazine.
International members who currently get the digital version of QST will see their fees go up by 20% from $49 to $59. The 3-year option goes up by 24% from $140 to $174.
International members who currently get QST by standard mail will see their fees increase by 25% from $76 to $95. The 3-year option goes up by 30% from $217 to $282.
Big changes as numbers fall... The last increase in membership fees was 8-years ago in 2016 so some may feel that an increase is inevitable. I suspect the size of the jump this time though will be too much for some.
In 2022, the ARRL saw an unexpected 4% drop in membership numbers as can be seen above. This I presume was due to the cost of living crisis and inflation and for some, ARRL membership was something they could do without. This suggests that ARRL membership is sensitive to price and all of this happened well before the price increase at the start of 2024.
The ARRL membership numbers since 2001 are shown above. You can see the strong growth up until 2015 and then the drop once the membership fee was increased from $39 to $49.
In 2016, the membership fees were increased when the numbers were at a peak. That is in marked contrast to now when membership seems to be in decline. They have yet to announce the 2023 membership numbers and there may well be a mini-surge as people avail of the lower prices before the prices go up.
However, the latest stats from the FCC shows that the number of radio amateurs in the USA has dropped about 2% in 2022 and is back down to roughly what they were in 2018. It seems that a large recovery in ARRL membership in 2023 is unlikely.
Does the ARRL represent radio amateurs in the USA??... At the end of 2022, there were just over 769,000 amateur radio callsigns in the United States. The ARRL membership at the end of 2022 was 151,840. This means that just 19.7% of radio amateurs in the United States are members of the ARRL. Back in 2015, that figure was 23.2%.
This seems to me to be a very low figure and it does raise the question about how any organisation can claim to be a national organisation when they can only attract less than 20% of the total number of radio amateurs in their country.
If we were to look at the UK, there are about 101,000 licences on issue. Due to multiple licences, this in reality means that there are almost 70,000 licensed operators. The RSGB has about 21,200 members which is about 30% of the amateur radio population in the UK. This is in marked contrast to the figure for the ARRL.
UK members of the RSGB receive the RadCom magazine and have to pay £65 per annum ($83) which is similar to the new ARRL fee. Why does membership of the ARRL in the USA seem so poor compared to the RSGB in the UK?
Looking ahead???... With membership falling and a hike in membership, it seems likely that the next few years will be turbulent ones for the ARRL. It currently represents less than 20% of radio amateurs in the USA and that figure seems likely to keep dropping.
If the membership numbers drop a significant amount then that's going to put pressure on the finances of the organisation and it's likely a review of costs will be needed. It's obvious that a full colour printed magazine that is posted out to members is going to be increasingly more expensive and difficult in the future.
As for a solution?... There are a multitude of posts online with people complaining about the ARRL but there seem to be very few solutions. Increasing the membership fees seems like a short term fix but I suspect it's only delaying the inevitable. Sooner or later, they're going to have to look at costs and make cuts.
From my own perspective, I used to be an overseas member of the ARRL in the late 1990's and early 2000's. At the time, information about amateur radio was at a premium and the QST magazine was very informative.
Fast forward to today and we have a multitude of websites, blogs, podcasts, social media, YouTube, etc. The ARRL as a content creator now has to compete with all of these other sources which are mostly free. It's already hard enough to keep up with all of the information that's available online for free without having to pay to look at what's behind a paywall.
Video... In this video, ARRL Director of Marketing and Innovation Bob Inderbitzen, NQ1R, chats with Kevin Thomas, W1DED, host of W1DED WW Ham Radio on YouTube, about the recent survey of members where 20,000 members responded and about the ARRL itself.
In summary... It's in no-ones interest to have a weak ARRL. As can be seen at the recent ITU conference in Doha, some amateur radio bands are under threat and the International Amateur Radio Union (IARU) needs strong member societies to support its work.
I suspect the next few years will be difficult ones for the ARRL as their membership seems likely to drop. They have an increasingly elderly membership base that wants things to stay the same in a world that is rapidly moving to digital.
It seems to me that that the next decade is likely to be a difficult one for the ARRL as they will have to make major changes to stay relevant.
Salvadaor, EA5Y near Madrid in Spain recently carried out some interesting tests on the 21 MHz (15m) band at the start of December 2023 and heard his own signal go twice around the world for a total path length of 80,000 kms.
First of all, let's set out the conditions. It's the 5th of December 2023 and the time is 08:30 UTC. Sunrise in Madrid is at 07:22 UTC which was about an hour earlier.
EA5Y is transmitting on 21.022 MHz using 1-kilowatt into a 4-element Yagi beaming at 240 degrees. He is sending a series of single dots and is listening for echoes.
The view from the antenna is shown above and 240 degrees is to the left of 'WEST' and should be close to 'VK2 long path'. There are mountains in the distance but they are some way off and EA5Y probably has a nice low angle of radiation from this antenna at this height.
Echoes... This is the audio plot from Salvador...
Going from the left...
1) He has a backscatter signal at 25-milliseconds which is too short for the human ear to separate from the initial dot.
2) The signal travels around the world and arrives back in Spain 40,000kms later.
3) The signal continues and goes around the globe a second time and arrives back 80,000kms after initially setting off.
Here are some interesting observations....
a) Salvador tried beaming to the north-east in the opposite direction and the echoes were much weaker. He wonders if the path was skewed? i.e. it's not as simple as the map at the top of the post would suggest.
b) He also tried listening to an online receiver based in New Zealand on the 2nd of December and this was 40kms from his antipodal point. You can hear the audio below...
You can clearly hear the signal reaching New Zealand for the first time at 20,000 kms and then going around the globe again to arrive back in New Zealand again at about 60,000 kms.
No doubt there is some antipodal focusing going on here and multiple paths and options appear for the signal instead of the usual short path / long path options.
As for the propagation mode, it's obvious via the F2 layer but there is probably some chordal hop involved with the signal going between different points of the ionosphere without needing a reflection off the ground.
We often see reports of long path echoes but it's interesting to see a report of a signal going around the world twice.
Further tests??? ... The obvious question is just how many times does the signal travel around the world? Are there times of the day when the signal is ever present going around the world multiple times before conditions change and the path breaks?
I wonder if it would be possible to decode some of the 2nd, 3rd, 4th, etc echoes with a digital signal? Something like the MSK144 meteor scatter mode using fast decode? Some other mode?
Is there some weak signal mode that is capable of decoding your own weak echoes without relying on looking at ticks on an audio plot?
Maybe there isn't but I'm just putting it out there in case someone wants to investigate.
