As beacons are often heard at very low signal levels, together with spurious signals, it is important the message is simple, unambiguous and repeated frequently. It is also necessary to have a period without information (“carrier”) for frequency checking purposes and signal strength measurement; and also to make it easy to distinguish the frequency when using F1A.
- For a coordinated beacon, the only essential information in the beacon message is the callsign.
The locator or other information is not essential
- The callsign should be sent in plain CW at least once per minute, not exceeding 60 characters per minute
- Beacons should include a period of plain carrier of approximately 20-30s, sufficient for frequency checking purposes.
- For mixed mode beacons, the MGM mode should start on the even minute, whilst the odd minute includes the plain carrier period. Effort should be made to ensure good timing accuracy of the even/odd minutes.
- It may be helpful to indicate a forthcoming change of mode by a short CW symbol (such as an ‘S’ or ‘X’)
- For beacons that are MGM only (which should only be exceptions to the other
recommendations) then the message should be MGM at the start, followed by the CW ID within a minute period.
Examples of these (with approximate message lengths) are illustrated below:- Simple 30 & 60 second
- Operation should be 24 hour continuous.
- If beacons change parameters during the transmission this must be reflected in the message transmitted.
- IARU Region-1 encourages best practice for both timing/frequency accuracy and phase noise to enhance general performance for the benefit of all.
- That development of new modes optimised for beacons are encouraged, which may either enhance DX reception or permit more efficient equipment (and thus lower electricity costs) to enhance sustainability
- That National Societies and IARU-R1 coordinators be kept updated on such developments.
Should MGM be implemented on a beacon, a standard 1kHz tuning offset should be adopted as per the example in the diagram. In any given frequency band, the specific MGM selection should have regard to the beacon frequency
spacing and MGM bandwidth
It is important that the operational parameters and the status of each beacon are widely known. The information should be sent to the IARU Region 1 VHF beacon coordinator via the local beacon.
Source: IARU-R1 VHF Handbook Version 8.01 November 2017 Page 97ff