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BeaconSee for Automated Beacon Monitoring

The BeaconSee Program
A new PC computer program for automatically monitoring the NCDXF/IARU beacons has revolutionized my use of the beacons and can do the same for you. The program, called BeaconSee, was written by Bev Ewen-Smith, CT1EGC. (Bev has previously held calls G3URZ, VK5AES and, long ago, VP8LB.) It runs under Windows 95 and Windows 98. You can contact Bev by e-mail at

The Hardware Setup
BeaconSee requires you to connect the audio output of your radio to the input of a 16-bit SoundBlaster-compatible sound card on your computer. You must also have your computer clock set accurately. BeaconSee then displays a plot of the audio frequency out of your radio as a function of time in a way that makes it very easy to identify which beacons are being heard.

If your receiver's listening frequency can be computer controlled, BeaconSee will cycle your radio among the bands you specify so that you can monitor as many bands as you wish. Since it takes three minutes to listen for all the beacons on one band, if you monitor all five bands BeaconSee can listen for each beacon on each band once every fifteen minutes and will then display the results for the past two hours on its screen.

The BeaconSee Screen
BeaconSee is an incredibly powerful tool for understanding current band conditions. I leave the program running all the time, and whenever I come into the shack I have an immediate assessment of the current propagation situation.

A portion of a typical BeaconSee presentation is shown in the accompanying figure. The data area of the screen is showing two bands, 14 and 21 MHz. These are labeled on the right edge. The 14 MHz band occupies the top part of the presentation and the 21 MHz band occupies the lower part. On each band, the presentation covers receiver audio output frequencies between 900 Hz and 1100 Hz, as indicated.

The results for the eighteen beacons are arrayed across the presentation, left to right. The illustration here shows a little more than nine beacons. The beacons are labeled at the top of the screen. On each band, the results of the previous eight ten-second monitoring periods are shown, the most recent time being on the right. Each ten-second beacon sample is comprised of five two-second readings.

The strongest beacon shown here is LU4AA on 21 MHz. Since two bands are being monitored, each beacon is checked every six minutes and the information about LU4AA on 21 MHz represents eight ten-second samples covering the past forty-eight minutes.

BeaconSee Screen Shot

Interpreting the Output
The white pattern for each sample of LU4AA on 21 MHz is triangular because the beacon transmission reduces in power over the course of the transmission. A stronger signal will show up as covering a slightly wider frequency range. The white pattern does not last the entire ten seconds because there is a quiet time between transmissions. This triangular "footprint" of a strong beacon is quite distinctive. The footprint and the regular repetition rate of the signal gives one confidence that it is actually a beacon one is seeing and not some other signal.

There is a lot more information in this picture. Notice that on 14 MHz, the OH2B and LU4AA beacons are not transmitting on exactly the same frequency. This example shows about a 50 Hz difference in their frequencies. Also, one can detect a slight drift on some of the signals over the forty-eight minute period.

With a little practice, QRM is easily distinguished from a real beacon signal. A constant carrier will show up as a horizontal line. Static will show up as a speckling. A random thirty second transmission will show up on three or four successive beacons in the same place in the time versus frequency space.

Even very weak beacon signals seem to be easy to identify by the repetition pattern. Look at the weak signals on 14 MHz for ZS6DN and OA4B. There is no doubt that these blips are really these beacons. Bev believes that his program can detect signals that one cannot hear. I have not convinced myself that he is correct, but, on the other hand, I have never heard a signal with my ear that his program did not also detect, and that in itself is amazing to me.

Free Download
You can download a free version of BeaconSee that will let you do everything described above. Go to

If you register your copy of BeaconSee, which costs US$29 (plus 17% IVA tax), there are some other great features that are available. A registered version will allow you to capture the screen periodically and store it as a disk file. Also, a registered version will allow you to sample at a slower rate, perhaps once an hour, so a screen can cover a longer period of time.

(Review by N6EK)