The 30m band runs from 10100-10150 kHz.

Australia is one of the only countries that permits SSB operation on 30m.

The existing band plan has SSB operation between 10125-10135 kHz, whilst digital uses 10130-10150 kHz.

This overlap is causing QRM between SSB and digital operators, particularly for the most popular digital mode, FT8 - which uses 10131 and 10136 kHz.

The only solution is to shift SSB operation down 5 kHz: 10120-130 kHz (10120-10127 dial/carrier frequency) - this alleviates the QRM whilst still leaving sufficient space for CW operation.

We wrote to the WIA on June 23 and August 14 to ensure a joint approach to the review.

We have discussed the issue with the WIA TAC coordinator, John VK3KM.  John has written the following amendment to the 30m plan (below).

Thanks to John and WIA President Grey Kelly for their cooperation.

 

TAC NOTES

30 Metres

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 it is 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. There are now three FT8 frequencies in use, 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 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