I got tired of monitoring FT8 signals on the 28 MHz band so I switched over to WSPR for a change. While I was listening during the morning, I heard an unusual signal on SSB.
It sounds like a slightly rough tone that lasts for about 7 seconds, stops for 1 second and then restarts as a different tone for another 10 seconds.
It then turns off for a second and the cycle starts again. The whole process seems to last for about 2-3 minutes.
The waterfall display above from the WSJT-X programme shows that the tones are in fact composed of several distinct frequencies.
It is not an amateur radio signal and I am assuming that it might be some sort of military OTHR (Over The Horizon Radar) signal but I have no idea about it's source?
Others must have heard this signal, anyone have any idea about its source???
Update: It looks as if this is Over The Horizon Radar (OTHR) from Iran.
"Ghadir, is an Iranian over the horizon radar Ghadir is a 360°, 3D-radar, with a ceiling of 300 km, and a maximum range of 1,100 km. You can hear a high and a low tone, corresponding to the sweep rates of 870 and 307 sweeps/sec. sent in two separated bursts."
This video from YouTube from IZ0KBA shows what it sounds like...
From the URE, the national body for radio amateurs in Spain..."New Radar OTH (Over The Horizon) in the 10-meter #radioamateur band. Received since the last week of October 2021. QRG: 28,000 kHz CF. AMOP. BW ca 45 kHz. 307 and 870 sps, alternately. IRN
This radar comes in addition to the Iranian one that broadcasts daily on 28,860 kHz CF, with the same bandwidth, but with a scan rate of 150 and 313 sps, alternatively.
The RADAR Over The Horizon Radar (OTH Radar, Radar beyond the horizon), is a type of radar system with the ability to detect targets at very long distances, typically hundreds to thousands of kilometers, beyond the radar horizon, which is the range limit for ordinary radar. Various OTH radar systems were deployed beginning in the 1950s and 1960s as part of early warning radar systems, but these have generally been replaced by airborne early warning systems.
The use of OTH Radars has receded nowadays, as the need for accurate long-term monitoring becomes less important with the end of the Cold War, and less expensive ground-based radars are once again being considered for functions such as maritime reconnaissance and surveillance of drug trafficking. However, old facilities are still in use and we are witnessing the creation of new ones.
Signal captured by the URE listening service, IARUMS URE (IARU Monitoring System, URE)."
Monday 1st Nov 2021: It was a case of Deja Vu as conditions on the 28 MHz band were almost identical to the previous day. A total of 981 stations in 65 DXCC countries were heard on FT8.
Beacons: During a short break, I had a listen around the beacon portion of the band and there was a Sporadic-E opening in full swing. The familiar beacons from Belgium and the Netherlands were coming through which meant the skip distance went as short as 1000kms.
EI7GL 28188.0 OE3XAC/B 13:04 01 Nov IO51TU<ES>JN78SB Austria EI7GL 28207.1 ON0RY/B 13:03 01 Nov IO51TU<ES>JO20CK Belgium EI7GL 28210.7 DB0FKS/B 13:02 01 Nov IO51TU<ES>JN49IT Fed. Rep. of Germany EI7GL 28214.5 FR1GZ/B 13:00 01 Nov IO51TU<F2>LG79RC Reunion Island EI7GL 28270.4 PY4MAB/B 12:59 01 Nov IO51TU<F2>GG68RE Brazil EI7GL 28273.0 DB0BER/B 12:55 01 Nov IO51TU<ES>JO62QL Fed. Rep. of Germany EI7GL 28301.8 PI7ETE/B 12:53 01 Nov IO51TU<ES>JO22QD Netherlands EI7GL 28279.0 DB0UM/B 12:51 01 Nov IO51TU<ES>JO73CE Fed. Rep. of Germany EI7GL 28265.0 DB0ANN/B 12:50 01 Nov IO51TU<ES>JN59PL Fed. Rep. of Germany EI7GL 28245.2 DB0TEN/B 12:49 01 Nov IO51TU<ES>JO42UV Fed. Rep. of Germany EI7GL 28225.0 YM7TEN/B 12:48 01 Nov IO51TU<F2>KN91RB Asiatic Turkey
It was nice to see some F2 signals (in bold) in there as well from Brazil and Turkey. The pick of the lot though was the FR1GZ/B beacon on Reunion Island in the Indian Ocean.
It's fine for my PC to decode a FT8 signal that may be buried in the noise but it's nice to actually listen to a CW signal coming though from an exotic location so far away.
Sunday 31st October 2021: I have no idea what is was like on the lower HF bands but conditions were really good on the 28 MHz band on Sunday.
I recorded a total of 1164 stations in 78 DXCC countries on FT8 which is really good. It seems to have been mainly due to a very good Sporadic-E opening to Western Europe as well as a very good F2 layer opening to the eastern half of the USA, South America and the eastern part of Europe. It probably helped that it was a Sunday and many people were off.
I had a quick listen to the SSB portion of the band and there were plenty of signals. It was nice to hear some CW beacons just below 28.3 MHz coming in from the USA for a change.
Friday 29th October 2021: I switched back to FT8 for this day to check for the aftereffects of the solar flare of Thursday on the HF bands. It looks as if the 28 MHz band has fully recovered although that might change on Sunday once the material from the flare hits the earth.
On the 29th of Oct, there was a nice opening to China and Australia. A total of 8 stations from Australia were heard on FT8 which is always nice on the 28 MHz band. I wouldn't be too bothered if this was on the lower HF bands.
Thursday 28th October 2021: I spent most of the day listening for WSPR signals on the 28 MHz but it was pretty poor mainly due to a lack of WSPR signals.
The big surprise during the day was the large burst of solar noise on the band in the afternoon. This sounded like a loud hissing sound and it was spread across the band.
Solar noise has a softer kind of sound as compared to electrical interference and it rises and falls in amplitude whereas electrical noise tends to be on/off.
The solar noise got up as high as S8 at one stage which is way above my usual noise floor of S1-2. It was so pronounced that I wrote down the time... 15:28 UTC.
I checked the X-Ray flux later in the day and sure enough, a big X1 flare had gone off on the sun at the same time I heard the solar noise.
You will notice from the image at the top of the post that the flare is pointing right at Earth. It's likely that the material ejected from the sun will reach the Earth this weekend resulting in possible auroral conditions and making a mess of the HF bands in general.
Update: The material is likely to impact the Earth after 21:00 UTC on the Saturday the 30th of October which will be almost in the middle of the CQWW SSB contest. The overall impact will be dependent on the magnetic polarity of the incoming material.
Video: Space weather physicist Dr. Tamitha Skov has a lot more detail about the event below...
Wednesday 27th October 2021: For a change, I decided to monitor the 28 MHz band for WSPR signals even though I knew the level of activity would be dramatically lower than FT8.
FT8 is a really good mode for monitoring band conditions and seeing what part of the world the 28 MHz band is open to. The problem for me is that when things start getting too easy and every days looks the same then I get bored.
The same happens in April of every year. I start off looking for the start of the Sporadic-E season with FT8 and seeing how it progresses. Once the season gets underway and there are hundreds of stations heard on FT8, I get bored and move to WSPR.
On the 28th of October, I heard just 28 stations on WSPR as compared to the usual several hundred on FT8. Despite the low number, it was enough to make it interesting.
The longest reception reports are shown below but it was nice to see VK2DVM near Sydney and the German Antarctic station DP0GVN make it through.
WSPR is far from perfect though. I heard nothing from North or South America and this was more due to a lack of stations rather than a lack of propagation.
Most of the WSPR signals heard were due to a Sporadic-E opening to Europe.
Tuesday 26th October 2021: As the solar flux jumped up to 109, it was another good day on the 28 MHz band with 538 stations heard on FT8 in 49 DXCC countries.
The band looked pretty similar to previous day although what stood out for me was the opening to China and Australia. These are some of the more interesting signals heard on the day...
Skip Zone: I'm sure a lot of radio amateurs monitoring the band have no idea what type of propagation is responsible for what they are hearing and some won't care. However some of the newer operators on the band may be curious.
In this post, I'm not going to get into what Sporadic-E and F2 layer propagation is as this is explained on many other websites.
I will however have a quick look at what the actual difference means on the 28 MHz band by looking at the map below from the 26th of October 2021.
Sporadic-E signals come off a layer in the atmosphere that is about 110kms up and the maximum range for signals is in the region of 2200kms. This is shown by the YELLOW line above. Even though the main Sporadic-E season is in the Summer months, we can still have plenty of Sporadic-E in October which is strong enough to support 28 MHz signals.
F2 layer signals come off a layer that is about 400kms up and as a result, the signals have a much greater range. F2 layer signals on 28 MHz are due to radiation from the sun and are getting better as we start heading back up towards the sunspot maximum in a few years. The GREEN line shows the minimum distance for F2 layer signals which for me is about the 2800km mark. Anything shorter and the angle is too high. Anything longer and it's probably ok out to a maximum one-hop range of 4000kms.
The map shows the skip zone for me on 28 MHz on the 26th of October 2021. If you are on 28 MHz then you will probably have a similar skip zone.
Just check the PSK Reporter website and see what you have heard in the last 24 hours. See if there is a gap out around 2200-2800kms.
Sunday 24th October 2021: This was a pretty good day on the 28 MHz band with 681 stations in 51 DXCC countries heard on FT8. In terms of numbers, that's about the same as a very good day at the peak of the Sporadic-E season during the Summer.
In this case however, it's a mix a some Sporadic-E to Europe and some F2 propagation to the rest of the world.
As always, it's the East-West propagation that is interesting. What I noted were...
b) RA9 stations from Asiatic Russia coming through. When I heard UA9/RA9 stations on 28 MHz then it's a good sign.
c) K7SP from Arizona.
d) Skip zones... If you look at the map, you'll notice a zone going through Bulgaria, Romania, the far west of Ukraine and European Russia. This is where the Sporadic-E stops (max distance) and the F2 propagation starts (min distance).
What's missing are stations from Japan and the west coast of the USA. As we get further up the solar cycle, those paths will be possible to stations with very modest antennas.
Saturday 23rd October 2021:This was a pretty big day on the 28 MHz band with 439 stations in 46 DXCC countries heard with the FT8 mode. The bulk of these were due to a Sporadic-E opening to Europe and a very good F2 opening to Ukraine & Russia.
The signals that caught my interest though were the three stations from Australia.
It was very unusual to hear VK4ZC near Brisbane on the east coast. As you can see, nothing else was heard along that northerly path. I have no proof but I suspect the path may have been skewed with the signals staying closer to the equator.
Friday 22nd October 2021: Compared to some of the recent openings on the 28 MHz, the day wasn't all that exceptional with 204 stations in 44 countries heard on FT8.
However, it's always nice to hear Australia on the 10-metre band. VK6JJJ in Perth is just over 15,000kms from my location.
Friday 15th October 2021: It wasn't a great day for propagation on 28 MHz but it was interesting all the same to see Australia coming through on FT8.
VK8NSB10mFT814315 km10:03:44
Everything is relative I suppose, it's down on other recent days but way ahead of the poor conditions at the bottom of the sunspot cycle two years ago.
There was some Sporadic-E from Spain and a reasonable F2 opening to Greece, Turkey, Ukraine and southern Russia.
A total of 151 stations were heard in 37 countries. The solar flux was 83.
Wednesday 13th October 2021: The big openings to the USA on 28 MHz seemed to have eased back a bit in the last few days and no two days seem to be the same. The 13th of October was a bit like that with an F2 opening to the east but very little to the west.
A total of 200 FT8 signals from 39 countries were heard on the day but most of these were due to a Sporadic-E opening to Europe. In truth, there weren't that many F2 signals in comparison to some of the openings of late.
The ones I found of interest were the signals from China which I think were the first for me this season. On 28 MHz, it's not always the stations that are furthest away that are the most interesting but it can be those East-West signals with the most northerly path.
Sunday 10th October 2021: I got a bit tired of listening for FT8 signals on the 28 MHz band so I decided to go back to WSPR instead. As I had expected, the amount of activity on this digital beacon mode was drastically lower.
I had the radio on from about noon on and as you can see from the map above, it's a bit sparse. I know that if this had been FT8, there would have been lots of stations heard.
The BIG surprise however was the German research station DP0GVN in Antarctica! Wow!
It's always interesting to see Antarctica coming through but it's really nice on 28 MHz. According to their WSPR page, they run 5-watts on WSPR.
The signal however was very weak here. According to the log, I had one single decode at -26dB which is well below what is audible by the human ear.
Looking at the map, there is other evidence of F2 propagation as well. During the Summer months, I used to hear VE1VDM in Nova Scotia via multi-hop Sporadic-E. On the 10th of October, it was very likely due to a single F2 hop as the solar conditions improve.
The solar flux on the day was at 85.
Addendum...
Related to 10m info on https://ei7gl.blogspot.com/ I would like to add, that yesterday, during Makrothen RTTY contest, there was interesting and excellent 10m opening towards USA. This is extract from S53M log.
Friday 8th Oct 2021: This was a really good day on the 28 MHz band with a total of 553 stations in 52 DXCC countries heard on the band.
The high number of stations was due mainly to two factors...
1) An extensive Sporadic-E opening to Europe which shows that even though we are in early October, there can still be Sp-E openings. It's not confined totally to the Summer months.
2) Good F2 layer opening especially to the eastern part of the USA.
As always, it's the East-West propagation that it the most interesting rather than what rare stations popped up. If the maximum usable frequency (MUF) was struggling to reach 28 MHz then all of the propagation would be North-South. The fact that I'm hearing stations in the USA and Russia on 28 MHz probably means that the MUF to the south for me was up above 30 MHz and into the low VHF spectrum.
It's interesting to note the sharp cut-off of the stations in the USA at about 6500 kms. This was likely due to the limit of two F2 hops and there wasn't a third hop to go further.
For me, the most interesting station was AB6A in Oregon. Not so much because of the distance but because of the northerly path.
The solar flux on the day was at 93 which is on the way back up again.
FT8 / SSB... I know all of these reports are for FT8 signals but it just happens to be the easiest way to monitor band conditions. If you operate on SSB only then get ready for the CQWW SSB contest at the end of the month. I expect the 28 MHz band then to be excellent.
Wednesday 6th October 2021: After a few modest days, there was a good opening on 28 MHz again with plenty of East-West propagation. Quite a number of FT8 from the USA were heard but the pick of the crop was W6IBU in California.
That makes California interesting is not so much the distance but the fact that the path was well to the north.
It was also interesting to see Mexico coming through as well as 3B9FR on Rodriguez Island in the Indian Ocean.
Between the extensive worldwide F2 opening and the Sporadic-E to Europe, a total of 488 stations in 54 DXCC countries were heard.
The solar flux on the day was 85.
Here are the maps for the previous few days but didn't really warrant an individual post.
Saturday 2nd October 2021: It looks like the 28 MHz band is on a bit of a roll at the moment with plenty of DX signals coming in from across the world every day. No two days are the same and the defining feature is how good the East-West propagation is.
On the 2nd, there was a very good F2 opening to the East but the multi-hop to SE Asia wasn't as good as the previous day. On the other hand, there was a good opening to the USA.
From my location in Ireland on the NW of Europe, the first and best F2 openings on 28 MHz are usually to the SE of the USA as this is the most southerly path. This turned out to be the case on the 2nd with a lot of stations from Florida making it through.
The most unusual signals were from Texas which required a more northerly path. This was another first for this season as these are the first signals that I have heard from the Lone Star state.
The Solar Flux on the 2nd was 87 and dropping. A total of 243 stations were heard on FT8 including 12 alone from South Africa.
The CQ WW SSB contest is coming up at the end of the month and I suspect all of the HF bands will be in great shape for it.
Friday 1st October 2021: The map above shows the 206 stations that I heard on 28 MHz during the day and it shows signals coming in from all over the world.
Considering I'm only listening with a simple half-wave vertical antenna, it shows that the band is really begin to open up as we climb out of the sunspot minimum.
There wasn't much in the way of Sporadic-E propagation to Europe and the main mode was F2 as the solar flux is at 91.
For some areas of the world, it seemed that the limitation what the number of stations that were active rather than how good the propagation was. Here are some of signals...
VK8NSB from the north of Australia, the first VK this season. There is always something special about an opening to VK from Europe on the 10m band.
49 stations from Indonesia, 13 from Israel and 10 from South Africa.
D60AC from the Comoros Islands, FR4OO from Reunion, VU3RGB from India and 4S7AVR from Sri Lanka.
5H1FF in Tanzania, 9G5FIin Ghana, V51MA in Namibia and 5T5PA in Mauritania.
It wasn't a great day towards the west with only one lone signal coming through from New Hampshire in the USA.
Thursday 30th September 2021: This was a mixed day in terms of propagation. On the one hand, a total of just 61 stations were heard on FT8 and there was a very little Sporadic-E propagation. The usual F2 opening to South America was subdued.
On the other hand, the was some interesting East-West propagation with stations further north in Russia and the USA coming through. It was also the first time I heard someone from Canada this season.
I have seen reports of plenty of DX on the lower bands where things are much easier in terms of propagation but I don't really have much interest in the lower HF bands.
Wednesday 29th September 2021: This day was a little bit more subdued than the 28th of Sept but there was still a nice mixture of Sporadic-E and F2 signals on the 28 MHz band.
What was of interest to me was the small opening to the USA which is a sign of the more elusive East-West propagation. It certainly wasn't huge as I only heard four US stations signals on FT8.
Overall, a total of 99 stations were heard with the solar flux jumping up to 102 from 89.
