WHATEVER HAPPENED TO THE 11-METER BAND?

Radio Nederland QSL card for the reception of a broadcast on 25650 kHz via the 
Talata, Madagascar relay station in 1981. (from the author’s collection)

WHATEVER HAPPENED TO
THE 11-METER BAND?

(This post is an edited version of an article I wrote for "The World of Shortwave Listening" column of The Spectrum Monitor magazine - August 2019 issue. Further details on this excellent publication are available at www.thespectrummonitor.com)


Recently, I was sitting in the radio shack mulling over the lack of activity on the shortwave broadcast bands. Sure, the solar cycle is still bouncing around on the bottom of the curve with little sign of recovering anytime soon, resulting in some pretty ghastly radio wave propagation on occasions. Of course, many of the international broadcasters and domestic regional stations have permanently left the radio dial. I dwelled on all this vacant space that is still assigned and available for use by world broadcasters. However, it is highly unlikely that we will ever see the shortwave spectrum fully utilized like it was back in the 60s, 70s and 80s.

Some allocated bands are hardly used at the moment. The old 120-meter tropical band (2300-2495 kHz) is not currently put into service by any broadcaster in the world. The nearest we get is the Korean Central Broadcasting Station (KCBS), Pyongyang on the out-of-band frequency of 2850 kHz. The 90-meter band (3200-3400 kHz) has a handful of South American, Indonesian, Papua New Guinea and several U.S. outlets. The sliver of spectrum known as the 75-meter band (3900-4000 kHz) is mostly the domain of a few Asian stations and occasionally Europe. The 60-meter tropical band (4750-5060 kHz) is but a shadow of its former self with just a few remaining Latin American broadcasters (Peru, Bolivia, Brazil), Asian broadcasters (including China, India, Bangladesh), plus several African outlets, Solomon Islands and two Australian low-powered operators.

However, the regular international bands of 49, 41, 31, 25, 22, and 19-meter bands are still busy with plenty of opportunities for shortwave enthusiasts to enjoy some pleasant listening over the 24-hour period. With the solar cycle currently in the doldrums, the 16-meter band (17480-17900 kHz) and the 13-meter band (21450-21850 kHz) have quite a number of frequency registrations with the HFCC, but some signals are only break through in the summer months. The little known 15-meter band (18900-19020 kHz), which was allocated to international broadcasting at the ITU’s World Administrative Radio Conference in 1992 (known as WARC-92), has not been used by any broadcaster in the last few years.

That leaves the long-forgotten 11-meter band (25670-26100 kHz), which hasn’t been seriously considered by broadcasters in decades! Whatever happened to this band, and why is it no longer in use?


Relying on the Sun

At its very basic level, we know that the high-frequency end of the shortwave spectrum relies on intense ionization from the Sun for the Earth’s upper atmosphere (the Ionosphere) to successfully and reliably propagate radio waves across long distances. Moreover, we know that these ionized conditions take place across those parts of the globe that are in daylight. We also know that the highest states of ionization occur during times when the surface of the Sun is activated through increased disturbances and times of high sunspot numbers. We have been observing the 11-year sunspot cycle since 1755. So we have got pretty good at predicting when future cycles will occur. What we don’t know and cannot predict is the exact start and end of each cycle, nor the highest and lowest points of each cycle.

The 10.7cm Solar Flux Index (SFI), the measure of the level of solar microwave radiation, is a helpful indicator of the daily effects of the Sun on the Ionosphere. When the SFI is, say 190 or higher, we can expect good openings of 21 MHz and above. When the SFI falls below 100, we see poor performance in high-frequency propagation. As I write this month’s column, the SFI is bouncing around 67, and propagation above about 12 MHz is problematic (to say the least!) here in the depths of the Australian winter!


Some 11-Meter Band Research

I decided to look back over the last 60 years for an indication of how broadcasters utilized the 11-meter band. Cycle 19 is regarded as the biggest solar cycle, peaking in March 1959 and with the highest recorded smoothed sunspot number (SSN) of 285. Older ham radio operators recall being able to work anything anywhere in the world “on a wet piece of string”. 21 MHz and up were absolutely singing! However, the international broadcasters hadn’t quite hit their straps at that time, and it wasn’t until Cycle 20 that the big powerhouse broadcasters really jumped into the 11-meter band. Interestingly, cycle 20 was nowhere as big as 19, peaking in November 1968 and chalking up a much lower SSN of around 156.

Time plays tricks on one’s memory. Just how good were the “good ol’ days”? The best way to find out was to do some research back into the old DX club newsletters that flourished around that time. Here in Australia, the largest and most vibrant DX club was the Australian Radio DX Club (ARDXC). During the SWL hobby boom through the 70s and 80s, this organization grew at an exponential rate with memberships in the many hundreds across the nation and internationally. The club still operates today, although it is significantly smaller than during the boom era.

Radio RSA QSL card for the reception on 25790 kHz in 1979, 
showing Durban “The Holiday City”. (from the author’s collection)

Digging out old copies of the Australian DX News (ADXN), I was able to gauge an understanding of just how busy the 11-meter band was during cycle 20. From those old newsletters, I have compiled the following list of active channels and broadcasters from the period of January to April 1970 (times in UTC, frequencies in kHz):

25610  R. Nederland-Hilversum in Dutch on Sundays 1000
25620  VOA-Delano in Burmese and English at 0030-0200
25650  BBC-UK in English to Africa between 0900 and 1400
25670  BBC-UK in Swahili at 0945, and at 1230 to 1415
25710  BBC-UK in English to Australia 0900-1400
25730  R. Norway in Norwegian 0700-0830, 1100-1230, 1300-1430
25750  BBC-UK in a variety of Asian languages 0930-1345
25790  South African BC in English 0700-1500
25800  VOA-Greenville at 1100-2200 using single-sideband reduced carrier for transmissions to Africa!
25840  Vatican Radio 0715-1400 in Italian
25880  VOA-Tangier (Morocco) in English 1300-1600 to Asia
25900  R. Norway 0700-0830, 1100-1230 using just 10kW!
25920  VOA-Greenville at 1500-1700 to Africa/Europe
25950  VOA-Monrovia (Liberia) at 1000-1100 in Mandarin
25950  VOA-Greenville to Europe 1300-1800
25990  VOA-Dixon in English and Thai to East Asia 2300-0200
26000  VOA-Bethany from 1300 to 2200
26040  VOA-Greenville 1145-1400 to Africa
26040  VOA-Bethany in English 1400-2200
26095  VOA-Dixon in Mandarin 2200-0100

So, although cycle 20 peaked in November 1968, we can see that two years later the 11-meter band was still very much in demand by broadcasters, even though cycle 20 was coming well off its highs. Bear in mind that the above list is just from observations made by Australian DXers. There may well have been other frequencies in use during that year but only audible to northern hemisphere listeners. From that cycle, I have QSL cards from Radio Nederland 25620 kHz and Radio Norway 25730 kHz.

AFRTS QSL card for reception on 25615 kHz from
the Delano CA relay station in 1981 (from the author’s collection)

Solar Cycle 21 peaked in December 1979 and around that time we started to see other international broadcasters using this band: 25605 Kol Israel, 25615 AFRTS Delano CA, 25640 Kol Israel, 25690 R. Liberty, 25730 R. RSA (Sth Africa), 25820 and 25895 R. France International, and 26020 HCJB (Ecuador). Interestingly, Israel was also operating well outside the 11-meter band using the higher frequencies of 27790 and 29705 kHz in Russian at 1000-1030 UTC, probably in an effort to avoid Soviet jammers.

From Cycle 21, I have QSL cards from VOA-Greenville NC 26040 kHz, AFRTS-Delano CA 25615, VOA-Poro (Philippines relay) 26000, R. France International 25850, R. RSA 25790, BBC-Rampisham 25710, Swiss Radio International 25780, and Radio Algeria on 25680 kHz. The signal strengths from these stations could be variable at times. However, when the reception was good, it was great, arriving crisply and clearly at the listener’s receiver without all the atmospheric static that plagues the bands below 10 MHz. Additionally, although being considered essentially a daytime-only band, signals could often be heard well into the late evening hours. Perhaps this was due to some type of residual ionization effect.


When Solar Cycle 22 hit its maximum in November 1989, the 11-meter band was utilized by the following stations: 25645 kHz Belgische Radio TV, 25670 Voice of the UAE, 25730 R. Norway, 25740 Deutsche Welle and R. Norway, 25750 BBC Daventry, 25780 R. Moscow, 25790 R. RSA, 25795 R. Yugoslavia, 25820 R. Denmark and R. France International, 25850 R. Denmark, 25900 Voice of the UAE, 25945 Radio for Peace (Costa Rica), and 26050 Belgische Radio TV. A point to note here: After having transmitted on many channels in the 11-meter band during cycle 20 as shown above, VOA and BBC appeared to have deserted the band completely during the solar peak of cycle 22.

The solar maximum for cycle 23 peaked in November 2001. At that time, the 13-meter band was utilized by many stations, but as far as I can tell, the 11-meter band saw only two channels in operation: 25740 Deutsche Welle and 25820 R. France International! The more recent solar peak for cycle 24 occurred in April 2014. No international broadcaster bothered to use the 11-meter band at all during that year!

Out of all those stations operating on 11 meters between cycles 20 and 24, only six currently broadcast on ANY band across the entire shortwave spectrum - R. Liberty, VOA, BBC, Vatican Radio, R. France International, plus Deutsche Welle (on a significantly reduced schedule!). None of the remaining broadcasters use the 11-meter band and haven’t done so for years.


Any Future for 11 Meters?

The end of the current cycle is expected to be formally declared in the coming year. As in a business or market cycle, the bottom of the solar cycle is only ever discovered well after the fact! However, we already know that cycle 24 had the lowest SSN since cycle 14 back in 1906. Many are making early predictions that cycle 25 could likely be near the lows of cycle 24. So, broadcasters will possibly be discouraged again from using the 13 and 11-meter bands as we swing around to the new cycle over the next few years.

As mentioned earlier, there are now far fewer international broadcasters today than existed three decades ago. Of those remaining active on the shortwave bands, I suspect that no station actively maintains transmitter and antenna installations ready for use on the 11-meter band. So, it is clear that this band is not likely to be utilized for international broadcasting anytime soon. Could the 25670-26100 kHz part of the shortwave broadcast spectrum be rescinded and re-purposed for another broadcasting mode or technology? Quite probably! However, it was a fascinating band while it lasted!

73 and good DX to you all!

Rob Wagner VK3BVW

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