Graham Hartlett, ZS6GJH

SARL and HMO to work on joint beacon project

The South African Radio League and the Hermanus Magnetic Observatory (HMO) have agreed to work on a joint beacon and propagation research project which will involve participation by many SARL members.

The project was announced by SARL President Graham Hartlett, ZS6GJH, during last Sunday's President's net and will be known as the SARL 40 Metre Beacon Project.

The beacon service will be of great value in confirming actual propagation conditions in real time for research and prediction of the ionosphere. The Space Physics Group of the HMO includes an active ionospheric component, and provides ionospheric data for the purpose of Space Weather predictions, which includes HF propagation prediction.

The HMO has recently become the Space Weather Regional Warning Centre for Africa, which includes amongst other parameters the provision of HF propagation predictions. Therefore, the current Space Weather provider and the HMO will now be working together to provide one Space Weather Centre for Africa.

The HMO will collect data from participating Radio Amateurs and Educational Institutions detailing the actual propagation paths between different areas in the country. This information will then be correlated with the HF propagation predictions that have been made for the given paths. In this way a validation procedure can be implemented and confidence levels placed on the predictions given out by the Space Weather Centre.

In addition, using information collected from the beacon service, student projects will be developed within the Space Physics group to improve the HF predictions over the South African region.

A number of volunteer Radio Amateurs will host beacons at their stations. A centralized database will be maintained that contains a record of each beacon, its host Amateur and its time slot.

Dr Bert von Rahden ZS6LP will coordinate the volunteer Amateurs and maintain the central beacon database, while John Williscroft ZS6EF will provide essential technical design and consideration and supply the 40 m beacons.

The 40 m beacon system has been modelled on the International Beacon Programme. Volunteer Amateur Radio Stations situated in all areas of South Africa will be provided with a 40 mW automatic beacon that will transmit within a prescribed time slot. This time slot is unique to each transmitter. The transmission period will be 55 seconds.

The 40 mW level has been determined by on the air experiments between a station in the Division 6 area (ZS6LP) and a station in the Division 2 area (ZS2VJJ). This level has been found to give the best dynamic range of varying propagation conditions.

The 40 meter beacon, which will transmit in the CW mode for a short period, will send out the following message; "ZSXXXX", Locator data followed by a 6 second tuning period, giving the division that the station is located in. The repeat period is every 30 minutes for stage #1, with each beacon transmitting in turn to a maximum of 30 beacons.

Each beacon will be internally clock synchronised before shipping to the stations. In addition provision has been made for a stage #2 mode with 60 beacons transmitting in a 60 minute period. The stations receiving on the designated frequency will hear a sequence of beacons from around the country. A list of beacons and their times of transmissions will be published so that stations not heard can be identified.

It is expected that the first 30 beacons will switch on in early October.

More details will be posted on www.sarl.org.za.