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?
