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30 Metres: Proposed AU Band-Plan Change

30 Metres: Proposed AU Band-Plan Change

The “NEWS”: The WIA Technical Advisory committee (TAC) proposal is to change the preferred (core) SSB segment to 10.120 – 10.130 MHz.

Background: As FT8 activity continues to increase, there is not much room to move on 30 metres.

Back in 2017 the 30 metre band plan was modified to address an interference issue between CW and SSB operators. It was recommended that whenever possible, SSB activity should be within the segment 10.125 – 10.135 MHz.

In other words, whenever possible – and bearing in mind the time of day – preference should be given to filling this segment before spreading down into the CW segment, or up into the digital modes segment.

This has been working moderately well, but the issue has arisen again due to a further increase in FT8 activity.

The “WHY”: There are now three FT8 frequencies in use internationally, and the lowest of these is 10.131 MHz.

Unfortunately this clashes with the recommended SSB segment extending up to 10.135 MHz. To keep the two modes apart, it will be necessary for SSB stations whenever possible to keep clear of frequencies above 10.130 MHz.

For USB operation, this means a dial (suppressed carrier) frequency no higher than 10.127 MHz.

So the proposal is to change the preferred (core) SSB segment to 10.120 – 10.130 MHz.

This is not a “silver bullet” solution as it is inconvenient for SSB stations, and for CW operators who also have to share the remaining band space with SSB.

But there is no real alternative. The frequencies used for FT8 are internationally co-ordinated, so we cannot tell the rest of the world to move. The only way to avoid QRM is to avoid the frequencies where it is happening.

John Martin VK3KM, TAC Coordinator
tac@wia.org.au

Note: Operators are requested to conform to this proposal from now prior to its formal ratification by the WIA TAC, subsequent update to the national band-plan and its submission for inclusion in the IARU-R3 band-plan.

About the WIA TAC: http://www.wia.org.au/members/tac/about/

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