Hunting For Daytime NDBs In CLE 220

AP-378 Mayne Island, BC

It's hard to believe but this coming weekend will see another CLE challenge!

No need however, to stay up until the wee hours for this one, as CLE220 is a mid-day affair ... just log what you are able to hear during the day from your location. The entire band is fair-game as well, from 190 - 1740kHz.

Everyone is encouraged to send their logs (see below) so the RNA / REU NDB databases can be kept as up-to-date as possible.

I know that I won't have any trouble hearing AP-378 shown above since it's only about 3/4 mile from my antenna! I'm always curious just how far it can be heard during the day and would encourage listeners on the west coast to have a good listen for it and please let me know if you can hear it.

For those unfamiliar with this monthly activity, a 'CLE' is a 'Co-ordinated Listening Event', as NDB DXers around the world focus their listening time  usually on one small slice of the NDB spectrum.

When tuning for NDBs, put your receiver in the CW mode and listen for the NDB's CW identifier, repeated every few seconds. With your receiver in the CW mode, listen for U.S. NDB identifiers approximately 1 kHz higher or lower than the published transmitted frequency since these beacons are tone-modulated with a 1020 Hz tone approximately.
For example, 'AA' near Fargo, ND, transmits on 365 kHz and its upper sideband CW identifier is tuned at 366.025 kHz while its lower sideband CW ident can be tuned at 363.946 kHz. Its USB tone is actually 1025 Hz while its LSB tone is 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 organizer Brian Keyte, G3SIA, comes the usual 'heads-up':

Hi all


How many normal NDBs can you log around midday?

In this event we can probably cheat the QRN and hardly hear any (but if
you do have a midday storm coming overhead, disconnect and switch off
immediately of course)

Listening around midday is a good way to check our listening stations and
to find out if changes really have made improvements in reception.
Or maybe you could try the CLE listening from a 'field' location instead of
(please, NOT as well as) from home?

Days: Fri. 23 June - Mon. 26 June
Times: Within 2 hours of ‘real’ Midday (see below)
QRG: 190 - 1740 kHz
NDBs Normal NDBs only, plus any UNIDs
(not DGPS, NAVTEX or Amateur)

### IMPORTANT ## If your house clocks have moved one hour
forward for 'summer time' (or 'daylight saving'), your listening
times each day will be BETWEEN 11 IN THE MORNING
and 3 IN THE AFTERNOON (15:00) on your LOCAL clocks.

If your clocks were NOT changed, maybe in Arizona (?), or
in the Southern Hemisphere where it is now mid-winter,
your times each day will be from 10 a.m. to 2 p.m. LOCAL.

(The above matches our agreed definition for daytime listening)
Of course, all our logs will show UTC times, as always.

Our usual simple log-making 'rules' apply:
Post your CLE log to the List in a plain text email if possible please,
with CLE220 at the start of its title, showing on each log line:

# The Day No.(e.g. ‘23’) or the full date (e.g. ‘2017-06-23’)
and UTC (the day changes at 00:00 UTC).
# kHz - the nominal published frequency, if known.
# The Call Ident.

Please show those main log items FIRST, with any other details such as
location and distance LATER in the same line.

Don't forget to give your own location and brief details of your equipment.
It also makes good reading if you add your thoughts on the CLE and any
amusing events that happened during it.

I will send the usual 'Any More Logs?' email at about 17:00 UTC on Tuesday
so you can check that your log has been found OK. Do make sure that your
log has arrived on the list by 08:00 UTC on Wednesday 28th June at the
very latest.
I’m so grateful to Joachim who will again be making the combined results for

As usual, you can get further helpful information about this and past CLEs
via Alan's CLE Information Section,
CLE107 was our last CLE rather like this one - way back in July 2008!

Good listening
From: Brian Keyte G3SIA [email protected]
Location: Surrey, SE England (CLE coordinator)

(Reminder: If you wish you can use a remote receiver for your loggings,
stating its location and owner - with their permission if required.
NB: THAT RECEIVER must be located within 2 hours of ‘real’ midday.
A remote listener may NOT also use another receiver, whether local or
remote, to obtain further loggings for the same CLE).

These listening events serve several purposes. They:
  • determine, worldwide, which beacons are actually in service and on-the-air so the 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. If you are a member of the ndblist Group, results will also be e-mailed and posted there.

The very active Yahoo ndblist Group is a great place to learn more about the 'Art of NDB DXing' or to meet other listeners in your region. It's also a good place to submit your CLE log! 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.

If you are contemplating getting started on 630m, listening for NDBs  is an excellent way to test out your receive capabilities as there are several NDBs located near this part of the spectrum.

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

'First-time' logs are always VERY welcome!

Reports may be sent to the ndblist or e-mailed to either myself or CLE co-ordinator, Brian Keyte (G3SIA), whose address appears above.

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.

Good hunting!

Steve McDonald, VE7SL, is a regular contributor to and writes from British Columbia, Canada. Contact him at [email protected].

2 Responses to “Hunting For Daytime NDBs In CLE 220”

  • Gary Pearce KN4AQ:

    Hmmm, I guess not everyone will be doing Field Day! I wondered what a CLE was, but you explained it soon enough. I’m confused about listening on SSB, though. I thought the NDB’s were all AM. Maybe SSB gives you more selectivity? I can usually hear three or four in the Raleigh NC area in the daytime, up to 30 miles away. Using an ICOM 756PROIII with a 150′ long dipole at 60′. But I won’t be able to play this weekend – I’ll be doing the Field Day thing.

  • Steve VE7SL:

    Hi Gary… You had me worried for a minute as I thought that I may have messed up. As indicated above, tune with your receiver in the CW mode (not in SSB modes), while looking for the CW signal identifier. They are AM modulated with a 1020 Hz tone so you can hear the tone on the carrier’s upper and lower sidebands. Keeping your receiver in the CW mode allows you to directly (and correctly) read the frequency as well as letting you use your narrow filters.

    The 756PRO III is a superb performer on LF and MF, as is the R-75. So many of the newer transceivers have dismal perormance below the broadcast band but you have one of the better ones.

    You can also listen on Friday or Monday around noon but I suspect that you will be at work like most folks!

    Good luck in the FD and hopefully the weather co-operates for you.

Leave a Comment

Subscribe FREE to's
Amateur Radio Newsletter
News, Opinion, Giveaways & More!

Join over 7,000 subscribers!
We never share your e-mail address.

Also available via RSS feed, Twitter, and Facebook.

Subscribe FREE to's
Amateur Radio Newsletter

We never share your e-mail address.

Do you like to write?
Interesting project to share?
Helpful tips and ideas for other hams?

Submit an article and we will review it for publication on!

Have a ham radio product or service?
Consider advertising on our site.

Are you a reporter covering ham radio?
Find ham radio experts for your story.

How to Set Up a Ham Radio Blog
Get started in less than 15 minutes!

  • Matt W1MST, Managing Editor

Sign up for our free
Amateur Radio Newsletter

Enter your e-mail address: