Amateur Radio on Longwave

(Updated 17 Jan. 2001-Further Revisions Soon)

Amateur radio was nearly synonymous with shortwave for many decades. In recent years, the 2m and 70cm bands have been representative of amateur radio. But longwave? Not since the very earliest years of radio, before commercial users began pushing amateurs ever higher in frequency. Of course, even as late as 1921, when the first amateur Transatlantic communication took place, 1350 kHz was considered shortwave. Still, the trend for amateur radio was clearly away from the part of the spectrum where radio was born.

Now, the tide is reversing somewhat. Europe has adopted a small amateur band at 136 kHz, and administrations in the South Pacific have been granting privileges in the 1750m band, which is presently used for low power, license-free experiments in the U.S. All this activity has again stirred interest in an LF band for North America.

With Canadian amateurs receiving special authority to use 136kHz this past year, the prospect of Transatlantic LF QSOs has inched closer to reality.

Within this page, you will find topics on:

  • The British 73 kHz band.
  • The new 136 kHz band in Europe.
  • Activity at 160-190 kHz in Australia, New Zealand and Papua New Guinea.
  • Progress toward allocations in the United States.
  • Activity involving BPSK and related digital modes.
  • Other amateur radio matters.

The British 73 kHz Band

In the spring of 1996, the UK Radiocommunications Authority allocated 71.6 to 76.4 kHz to holders of Class A amateur licenses in the British Isles. Operation is on an experimental, non-interference basis, and is conducted under individual Notices of Variation.

The band was activated, in part, as a stopgap while the rest of Europe debated possible allocations. After 136 kHz was agreed upon, the RA quit issuing NoV at the end of June, 1998, and operation on this band was supposed to cease two years later. In Spring of 2000, the RA agreed to allow extend the cutoff a year, until June 2001. No new Notices of Variation were to be issued, but future discussions about continued use of the band were not ruled out.

In the late summer of 2000 came word that existing NoVs were being renewed for three years...and in late autumn came word that some new NoVs are again being issued.

The amateur community's interest arose from a desire to investigate propagation through the ground by transmission from underground caves. Activity is not limited to caving, however. Basically, operating specifications are:

Frequency: 71.6kHz to 74.4kHz
ERP: 0dBW (1 Watt)
Modes: All that fit the bandwidth.
Location: At the main station address. Or, at a temporary
    location with 7 days prior notice. No mobile or maritime mobile.

The press release announcing the initial allocation is still available. Return here by using your browser's Back button.

Good ways to stay informed of activity on this band are through the RSGB Web site and the RSGB LF Group e-mail reflector. Please refer to the 136 kHz section below.

Return to List of Topics, above.

The 136 kHz Band in Europe

A major step has been taken toward realizing the long-standing dream of an amateur Transatlantic QSO on longwave. A crossband QSO between the United Kingdom and Canada was completed at 0008UTC on 10 September, 2000. David Bowman, GØMRF, was operating on 135.71 kHz and John Currie, VE1ZJ, was operating on 14,043 kHz. Here is a link to a partial digest of e-mail activity on the RSGB LF reflector about the big event. In addition to scores of congratulatory messages, you will find details of how the feat was accomplished.

More recently, Canadian signals have been heard in Europe--most recently, VE1ZZ. With winter propagation near its peak at this writing, prospects are about as good as they may get for a QSO this season.

A Brief History of the Band

Early discussions of an LF ham band in Europe apparently included possible allocations around 143 or 147 kHz, but consensus was eventually built for a band at 135.7 - 137.8 kHz. When a working group of the Conference of European Post and Telecommunications (CEPT) issued their report in early 1997, several administrations began rulemaking proceedings or issued special permits for use of the band.

The full CEPT recommendation was issued in September, 1997, followed by further action in several nations. On January 30, 1998, the United Kingdom opened the band within its borders, resulting in some of the most prolific activity to date.

Who Is On The Band

Here is a snapshot of European assignments, more or less up to date as of late 2000. All 135.7 - 137.8 kHz unless noted. If you have additional details for your country, please contact Thanks!

Mode=CW (A1A) only
Power=1W ERP/2000W TPO
Holders of HF licences can apply for a special permit.


Since 1 April 1997
All CEPT class 1 Amateurs
Power limit 100W TX output

1W ERP max.
Since Apr 21, 2000.

January 1999
Class 1 license holders
20 W PEP transmitter power
Max. mod. bandwith=800 Hz

Since Jan 1, 1998
By permit; see link.
100 W; 1A1 and J3E

Since March 26, 1998
1 W ERP; secondary basis
100 W; 1A1 and J3E

100 W TPO
Advanced and Extra Class

Details Pending

Details Pending

TPO=400 W Max ERP

Details Pending

August 2000; apparently
  by individual license.

Since July, 1998
TPO: 100 watts

Details Pending

August 2000; apparently
  by individual license.

Max. 1 Watt ERP

Since 1 Jan 1998
Max. 1 Watt ERP

Since 30 Jan 1998
All CEPT Class 1 Amateurs (Class A in UK)

For listings of active stations, and those potentially available for QSO schedules, please consult the
European Amateur LF Schedules list maintained by Chris Trayner G4OKW.

Internet Resources for the 136 kHz Band:

(European Hams! We would be grateful for any information on LF activity in your country. If your amateur radio organization has a Web page, we would be glad to list it here, especially if there is an LF ham assignment where you live. It is not necessary for the page to include English. You may send e-mail from here.)

Return to List of Topics, above.

Australia, New Zealand, Papua New Guinea

Amateurs in this region have been looking to longwave frequencies for some time. Hams in Papua New Guinea and New Zealand have had operating privileges on 160-190 kHz and 165-190 kHz, respectively, for several years. Australians have been able to operate by special permit. Contacts over distances of more than 150 miles have been made between ZL hams and experimental licensees in VK. One-way reception of ZL stations at 1100 km has also been reported in Australia.

There is now movement toward permanent status of a longwave ham band "down under." A liason tem involving the Wireless Institute of Australia and the Australian Communications Agency is working on a proposal for a ham band between 100 and 200 kHz.

In fact, WIA is asking for the entire 100 - 200 kHz octave to be allocated to amateurs, except for guard bands for certain services! Check out this excerpt from the online WIA News bulletin for January 1988 for some very interesting reading!

Principle amateur organizations in the region:

Individual and group pages:

Return to List of Topics, above.

Prospects for North America

Although U.S. LF ham privileges remain in limbo (see below), Canadians have lately been able to apply for special authorization for 136 kHz and are tantalizingly close to achieving Transatlantic QSOs. (See the European 136kHz section, above.) VE1JZ has been honored with the Peter Bobek Memorial Award for his part in the first cross-band HF/LF transoceanic QSO.

A new amateur licensing structure took effect in the United States on April 15, 2000, including only three basic license classes, and a 5 word per minute code requirement for all classes eligible for HF. We may hope that this will make the proposed U.S. LF ham bands (if or when they are approved) available to a higher percentage of the experimenters who presently use the 160-190 kHz no-license frequencies that may be incorporated into the ham bands. An ARRL petition for a band at 136 kHz and another at 160-190 kHz has been under consideration by the FCC for over two years.

The present occupants of the 1750m band have led the way in development of CCW, BPSK, and other advanced digital techniques, out of sheer necessity. Some of them feel--probably quite rightly--that a conventional amateur band here would spell the end of the opportunities and challenges that exist under the current no-license rules. On the other hand, there are serious-minded experimenters who see a need--again, probably quite rightly--for an LF amateur band where advancement of the radio art can be conducted with a little higher signal-to-noise ratio.

The rationale behind a 160 - 190 kHz assignment is, apparently, that little engineering study would be necessary to assess the impact upon present users of the spectrum. However, there are good arguments against the 1750 m band as an ideal place for LF amateur activity. Although there is no private maritime mobile operation in this segment (one allocation factor that favors it over, say, 130 - 160 kHz), there are other factors which might prevent its continent-wide use...such as aeronautical fixed services having primary status in Alaska and parts of Canada.

In addition, the 1750 m band is within the LW broadcast band in Region 1, thus eliminating any possibility of intercontinental DX. Allocations below 147.5 kHz would be needed to make that even a remote possibility.

Closure of the military's Groundwave Emergency Network (GWEN) packet system removed one of the last obstacles to using the lower half of the 1750 meter band, so ARRL's attorney filed a petition with the FCC on October 22, 1998. You can read the petition in one of the following formats:

It has been assigned Docket Number RM-9404, which will be used to track its progress through the rulemaking process.

In addition, the Amateur Radio Research and Development Corporation (AMRAD) applied for an Experimental Radio Service (Part 5) license to conduct tests on 136.750 kHz with 1W EIRP. This operation has now been underway for some time from different locations in Virginia. Their LF Page will keep us informed of developments, and also includes latest word on field tests attempting to copy European LF ham signals in North America.

Want to Become a Ham? Information and assistance on getting an amateur license in the U.S. is available from HamTest, sponsored by ADI.

Return to List of Topics, above.

Unique Digital Modes

BPSK, PSK31, and Related Techniques

Longwave experimenters in the U.S. and Canada, limited as they are to 1 watt transmitter input power and a 15 meter antenna, have long appreciated the benefits of advanced digital modes, and were active in the development of practical, inexpensive hardware and software for Binary Phase Shift Keying and Coherent CW, in particular. Those modes have since become popular with hams on HF too.

While BPSK and CCW require hefty amounts of precision at both ends of a communication circuit, there's a technique that substitutes time, and a convenient form of DSP at the receiving end, in place of more advanced modulation schemes. Very slow CW, with dot lengths on the order of seconds or even minutes, has proven successful on the noisy LF band in Europe. Only reasonable transmitter and receiver stability are required, and the message is read visually from a long-term FFT spectrum analyzer display.

We will eventually have an entirely separate page devoted to these topics. For now, you will still find useful information on CCW, BPSK and other useful modes, through the following links and resources:

  • Bill de Carle's Web site, the authoritative source for the COHERENT and AFRICA software for BPSK.
  • Lyle Koehler's Web site, with a good explanation of BPSK.
  • Ko Versteeg's Archive From PSK to Hellschreiber, and several popular weak-signal receiving programs.
  • The PSK31 Page Information on this spectrum-efficient mode, and how to subscribe to the PSK31 e-mail list.
  • Clint Turner KA7OEI PSK31 beacon based on a PIC.
  • 'BPSK Adventures' Article by Bill Cantrell from the K3PGP site, which also contains other LowFER-related information.

  • Slow CW Transmitting Software. Rik Strobbe's free Windows program for transmitting extremely slow CW (QRSs), a mode which has been used with much success on the noisy LF amateur band in Europe. Version 2.05 now includes support for Differential Frequency CW mode, also known as VCW (Visual CW). Read more about it and download the program by clicking here. You may find it useful to visit Mike Dennison's page describing the VCW mode in more detail.
  • R. S. Horne's Spectrogram FFT analyzer is available on the Web. Download at Excellent for analysis of natural-radio signals (whistlers, etc.), among other applications. For 32-bit Windows. Some earlier versions for Windows 3.1 are still available through the LWCA File Library.
  • A special radio-oriented version of Spectrogram includes a variable time scale and cursor frequency offset not included in the regular edition; especially desirable for very slow CW and other weak-signal modes. Download it here; approx. 170 KB zipped.