General access to the 630 m band in Canada

Since 2014 Canadian hams have access to the 630 m band, but until recently a special authorisation was required.
However on 28 July 2022 the Standards for the Operation of Radio Stations in the Amateur Radio Service (RBR-4) were adapted, giving all holders of a "B and 5", "B/H" or "B and A" operators qualification access to the band.

[Info: Joe, VO1NA]

Daily report published on NJDTechnologies.net will stop on January 31th

John, KB5NJD, reports that on January 31 the last daily report will be published on NJDTechnologies.net after nearly five and a half years of providing public content.
His web host is preparing to make software upgrades that will conflict with his site. Because there are nearly 2100 posts (about 40000 8.5 X 11 pages if you printed them all out), estimates suggest that it will cost multi-kilobucks to upgrade the site to functionality and a normal presentation after the upgrade is complete in February.

I believe I do speak on behalf on the LF / MF community and beyond by thanking John for the many years of "hard labour", producing 365 days a year his daily reports and maintaining his excellent LF / MF site. It will be missed by many!

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Austria on 472 kHz

On December 21 2020 Austrian hams holding a HAREC licence (Bewilligungsklasse 1) gained access to the 630 m band. The power is limited to 1 W EIRP, there are no particular mode or bandwidth restrictions.

Martin, OE3EMC, is already QRV and has been copied (and worked) in JT9.

2 new modes especially for use on LF and MF added to WSJT-X

WSJT-X version 2.3.0 offers two new modes designed especially for use on the LF and MF bands. FST4 is for 2-way QSOs and FST4W is for WSPR-like transmissions.

Both modes offer a range of options for T/R sequence lengths and threshold decoding sensitivities extending well into the -40 dB range. Early tests have shown these modes frequently spanning intercontinental distances on the 2200 m and 630 m bands. Further details and operating hints can be found in the Quick-Start Guide to FST4 and FST4W.
This version of WSJT-X can be downloaded from the WSJT-X homepage (scroll down to find version 2.3.0).

Be aware that the current version (2.3.0-rc1)  is a beta-quality release candidate.

W5EST 2019 630 meter yearbook now available for download

Jim Hollander, W5EST, has provided analysis and commentary on a number of topics related to amateur activity and on-air observations for 630 meters on my blog for several years now.
Multiple volumes have been available for download reflecting 2016 and 2017/2018 and now, a 2019 compilation is available for download. The 2019 table of contents, with links to the individual PDF chapters, can be found here:

The table of content for all of the volumes can be found here:


Congratulation to Jim for taking the time to sort through reams of data and "think outside of the box" in an effort to offer a better understanding of some of the things experienced and observed on the air. 

[info: John, KB5NJD]

Brazil on 472 kHz starting 30 november 2018

Marcus, PY2PLL, informed me that ANATEL (Brazil's telecom agency) Resolution 697 of 28 August 2018 (published 31 August 2018) includes the release of the 472-479 kHz range to the Amateur Service on a secondary base.

- Secondary service
- Power limit of 5 W EIRP
- No mode or bandwidth restrictions
- Only Class A licencees

The resoltion becomes effective 90 days after publication.

Antartica listening on 630 m WSPR (updated 12 March)

Stefan, DF7FC, informs that since a few weeks the German Antarctic research station Neumayer III is running a Red Pitaya on a wideband RX antenna to receive/decode/upload WSPR reports on up to 8 bands simultaneously. You may have noticed them already on the WSPR map on other bands. There are regular spots on 160 m from Europe.

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New digital mode for LF/MF

Three years ago ZL2AFP introduced a weak-signal QSO mode specifically for the LF/MF bands. The mode has now been updated and enhanced, and is capable of comfortable QSOs at down to -25 dB SNR, so almost as sensitive as WSPR.
However, the new WSQCall V1.00 is a QSO mode, and also has selective calling capability, plus automated responses and the ability to send and receive files. The protocol is the same as for FSQCall, so should be familiar to existing users.

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Argentina on 472 kHz starting 8 February 2018

Alejandro, LU8YD, informed me that in October 2017 the communications regulation authority of Argentina (ENACOM) approved a new regulation for the amateur radio service that will come into force on February 7, 2018. In the new regulation, the amateur radio service is authorized to use 472-479 kHz band. Also the authorization of the 137 kHz band is ratified.
Following restrictions apply for 630 m:

  • Power: maximum 5 W EIRP
  • Bandwidth: maximum 500 Hz
  • Modes: CW and digimodes
  • Licence classes: all (novice, general, superior and special)
A new kid on the block

The past days the new FT8 mode has shown up on 630 meter. From the operators side FT8 is pretty similar to the well known JT9 mode, but 4 times faster. With a 15 seconds transmision cycle a basic QSO can be completed within 1 minute. But there is no such thing as a free meal: the increased speed comes at the expense of a ± 6 dB loss in sensitivity and a 3 times larger bandwidth (compared to JT9).
But compared to CW FT8 is very competitive, in regard with speed as well as sensitivity (although the true CW operator might prefer the "gusto" of CW).

Some useful links: 
WSJT-X Version 1.8 download page 
WSJT-X User Guide
Tips for FT8 DXers

USA on 472 kHz (very soon)

On 15 September a FCC document "WRC–12 Implementation Report and Order" was published, announcing the immediate release of the 472-479 kHz band (and the 135.7-137.8 kHz band) for the amateur radio service.
However, the document also states that prior to commencement of operations amateur operators must notify the Utilities Telecom Council (UTC) of their intent to operate by submitting their call signs, intended band(s) of operation and the coordinates of their antenna’s fixed location. Amateur stations will be permitted to commence operations after a 30-day period unless UTC notifies the station that its fixed location is located within one kilometer of Power Line Carrier (PLC) systems operating on the same or overlapping frequencies.
This means that the first US station can be expected on 630 m in mid october, just in time for the winter season.

UPDATE 15 October: John, AE5X, just reports that the first approval notifications were received from UTC.

Weak signal modes pages

In the year 2000 I did write a 'Extreme narrow bandwidth techniques' page. At that time narrow bandwidth modes such as QRSS and DFCW where the only weak signal modes used on LF. But a lot has changed since then. Starting with WOLF, a number of FEC based weak signal modes were developed. Now modes as WSPR, Opera and JT9 are widely used on the 630 m band. In addition some real time weak signal modes, as WSQ appeared. So it was about time to write an updated version dedicated to all weak signal modes used today (and in the past), integrated in the 472kHz.org site.

Go to the Weak signal modes pages

Brazil on 472 kHz in fall 2017?

Franco, PY1EPU, informed me that ANATEL (Brazil's telecom agency) has scheduled the assignment of 472 - 479 kHz to the amateur service for october 2017.

Conditions to be expected:
- Secondary service
- Power limit of 5 W EIRP
- CW and digital modes
- Only Class A licencees

472 kHz in USA soon?

The Federal Communications Commission order FCC 17-33, dated March 29th 2017, adopts rules to implement certain radio frequency allocation decisions from the World Radiocommunication Conference (Geneva, 2012) (WRC-12) and conforms the rules to the WRC-12 Final Acts.
One of the items is to allocate the 472-479 kHz band to the amateur service on a secondary basis.

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Cellar-Dwellers on the go!

Around mid-last year VK5BUG's first multi-author volume, "MF Down Under" an edited VK-compendium of articles and projects for the 630 & 160 m bands was released: 344 x A4 pages, nine chapters, 44 articles from 15 authors.

Now Doc is pleased to advise you that its sequel and companion text "Cellar-Dwellers on the go!" an edited international compendium of resources, articles & projects for portable and transportable operation on the LF & MF amateur bands, is currently with the printer & is scheduled for launch/release at the 2017 Wireless Institute of Australia AGM on 20 May in Hahndorf, South Australia.

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The principle of forward error correction

Paul Nicholson wrote an excellent article explaining the fundamental principle behind forward error correction codes.
It does not discuss any particular coding scheme (Convolutional, Reed-Solomon, LDPC, and so on), rather, the intent is to home in on the underlying principle that all forward error correction schemes exploit. This is done so without using any mathematics at all, well perhaps just a little simple arithmetic.

Read the article.

Australia - Canada QSO on 630 meter

On September15th Roger, VK4YB, and Steve, VE7SL, successfully completed a two-way JT9 QSO after a few previous attempts. With a distance of 11802 km, this QSO is believed to be the longest two-way QSO ever completed under amateur service rules on 630 meter.

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IARU Regon I Interim Meeting 2016

At the IARU Region 1 Interim Meeting (Vienna, 16-17 April 2016) the Norwegian society NRRL introduced a proposal to introduce a beacon segment from 476 - 477 kHz.

This proposal was declined by a vast majority.

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Propagation page

Alan, G3NYK, did write a great article on medium wave propagation that I proudly added to the 472kHz.org website.

Have a look at it!