Wednesday 25 October 2023

Hunting For NDBs In CLE279

Another month has zoomed by and it's CLE time once again. This is a challenge for all newcomers to NDB listening and the ultimate test of your medium frequency receiving capabilities. Can you meet the challenge?

'CLE's are 'Co-ordinated  Listening Events, and NDB DXers around the world focus their listening time on one small slice of  the NDB spectrum.
With the number of targets slowly being decommissioned, the hunting grounds have been slightly widened ... this month the frequency range is for the NDBs whose published frequencies are between 335.0 - 349.9 kHz

When tuning for NDBs, put your receiver in the CW mode and listen for the NDB's CW identifier, repeated every few seconds. Listen for U.S. NDB identifiers approximately 1 kHz higher or lower than the published transmitted frequency since these beacons are modulated with a 1020 Hz tone approximately.

For example, 'AA' near Fargo, ND, transmitted on 365 kHz and its upper sideband CW identifier was tuned at 366.025 kHz while its lower sideband CW ident could be tuned at 363.946 kHz. Its USB tone was actually 1025 Hz while its LSB tone was 1054 Hz.

Often, one sideband will be much stronger than the other so if you don't hear the first one, try listening on the other sideband.

Canadian NDBs normally have an USB tone only, usually very close to 400 Hz. They also have a long dash (keydown) following the CW identifier.

All NDBs heard in North America will be listed in the RNA database (updated daily) while those heard in Europe may be found in the REU database. Beacons heard outside of these regions will be found in the RWW database.

From CLE organizers comes the following info:

Hello all

Here are the full details for this weekend's co-ordinated listening event.
It is open to everyone including CLE new-comers:

    Days:       Friday 27 Oct. - Monday 30 Oct.

    Times:     Start and end at midday, LOCAL time at the receiver.

          NB:   Most of us are changing our clocks by one hour this weekend.

                   However UTC time (as shown in our logs) continues unaffected.   

    Range:     335.0 - 349.9 kHz

Wherever you are, please join us and log the NDBs that you can positively
identify that are listed in this busy frequency range (it includes 335.0 kHz
but not 350 kHz), plus any UNIDs that you come across there.

Short and long logs are welcome (in-between ones are good too!)

    Send your CLE log to the List, preferably as a plain text email
    (not in an attachment) with ‘CLE297 FINAL’ in its subject line.

    Please show on EVERY LINE of your log:
       #  The date (e.g. '2023-10-27' or just the day no. '27') and UTC
           (the day changes at 00:00 UTC).
       #  kHz  (
The beacon's nominal published frequency)

              If you don’t know it, please visit

              where you will find all the details.
       #  The Call Ident.

Show those main items FIRST on each line, before other optional 
details such as Location, Distance, etc.  If you send any interim logs during the event, please also send your 'FINAL', complete, log.

Always make your log interesting to everyone by giving details of your listening location (the 6-character Locator) and brief details of the receiver, aerial(s), etc., that you were using.

We will send the usual 'Any More Logs?' email at about 19:00 UTC
on Tuesday so that you can check that your log has been found OK.
Do make sure that your log has arrived on the List at the very latest
by 08:00 UTC on Wednesday 1 November.  We will then hope to 
complete making the combined results within a day or two.

You can find full information about current and past CLEs from the

CLE page

You can also find your relevant seeklists made from REU/RNA/RWW by visiting

Good listening


   Brian and Joachim

   (CLE Coordinators)

(Reminder:  You could use any ONE remote receiver for your loggings, stating its location and owner - with their permission if required. A remote listener may NOT also use another receiver, whether local or remote, to obtain further loggings for the same CLE)


CLE's provide several purposes. They:

• determine, worldwide, which beacons are actually in service and on-the-air so the newly-re-vamped Rxx online database can be kept up-to-date

• determine, worldwide, which beacons are out-of-service or have gone silent since the last CLE covering this range

• will indicate the state of propagation conditions at the various participant locations

• will give you an indication of how well your LF/MF receiving system is working

• give participants a fun yet challenging activity to keep their listening skills honed

Final details can be found at the NDB List website, and worldwide results, for every participant, will be posted there a few days after the event.

The NDB List Group is a great place to learn more about the 'Art of NDB DXing' or to meet other DXers in your region. There is a lot of good information available there and new members are always very welcome. As well, you can follow the results of other CLE participants from night to night as propagation is always an active topic of discussion.

You need not be an NDB List member to participate in the CLEs and all reports, no matter how small, are of much value to the organizers.

Remember - 'First-time' logs are always VERY welcome!

Reports may be sent to the NDB List Group or e-mailed to CLE co-ordinator, Brian Keyte (G3SIA), whose address appears above. If you are a member of the group, all final results will also be e-mailed and posted there.

Please ... give the CLE a try ... then let us know what NDB's can be heard from your location! Your report can then be added to the worldwide database to help keep it up-to-date.

Have fun and good hunting!