Mr. Chris Worley
Spectrum Planning Section
Australian Communications and Media Authority
Via on line submission
Dear Mr. Worley,
CONSULTATION PAPER – POSSIBLE USE OF 5351.5-5366.5 BY THE AMATEUR SERVICE
Thank you for the opportunity to comment on the above consultation paper. The Radio Amateur Society of Australia (RASA) offers the following comments.
Upper band limit
We agree that the number of stations and their wide geographic dispersal on the 5366.5 kHz allocation would preclude any sharing with amateur services on the eastern seaboard.
For this reason, it is proposed that the upper end of the band be restricted to 5365 kHz.
Sharing with commercial services
Data from the ACMA RADCOM database as presented in your paper indicates that the remainder of the band below 5365 kHz is allocated to commercial services in remote and very remote locations.
ACMA Frequency assignment practice guideline number 8 defines an indicative communication distance of approximately 300 km at 5 MHz during daylight hours, based on a typical transmitter power of 100W.
The 15W EIRP limit granted to amateurs and the remote locations of the incumbent services means that there is minimal potential for interference.
The only channel that is located relatively close to population centres – 5356.5 kHz at Dubbo NSW – has been shared with WICEN for more than ten years, with no reports of interference. Moreover, WICEN operate under a land mobile licence, which allows 100W transmit power.
Although the public RADCOM database does not list all Defence allocations, Defence does not normally directly share channels/segments with commercial land mobile services.
Proposed way ahead – Option 3
We understand why there would be reticence to giving amateurs immediate unrestricted access to what is a commercial land mobile segment.
Other administrations have taken a graduated approach to the introduction of the 5 MHz amateur band, and we suggest that this strategy would be appropriate for Australia.
A channelised arrangement has been used in many other countries to introduce the 5 MHz amateur band – notably, UK, Europe, the USA and New Zealand. These countries all have high commercial utilisation of 5 MHz and much shorter distances between amateurs and commercial users than Australia.
Allowing unfettered access to the segment would make any sharing issues very difficult to resolve, as amateurs may not be operating directly on commercial frequencies.
Accordingly, we propose that amateur voice operation be restricted to spot frequencies on the existing commercial allocations, using USB mode only with a maximum 2.8 kHz bandwidth and 15W ERP.
Additionally, we propose a trial of narrow band modes in two vacant sub-segments, one of which lines up with a very popular world-wide amateur digital mode frequency (FT8 mode).
Amateur licence class
In view of the small size of the allocation and the technical requirements, it is proposed that the band be available to Advanced class licencees only.
The proposed allocations are detailed in the table at Annex A
16 June 2020
ANNEX A – PROPOSED AMATEUR ALLOCATIONS AT 5 MHZ
|Freq (note 1)||Use|
|5351||Voice (notes 2 and 3)|
|5355||Voice (note 3)|
|5358-60||Narrow band modes (note 4)|
|5360||Voice (note 3)|
|5363-65||Narrow band modes (notes 4 and 5)|
- Voice frequencies expressed as suppressed carrier; narrow band sub bands expressed as occupied frequencies. Maximum power output 15W ERP for all modes.
- It is noted that this frequency is 500Hz below the lower band limit, however this is proposed as a trade-off for the proposed reduction of 1.5 kHz at the top of the band to mitigate against interference to a very large Queensland allocation.
- Voice channels are fixed frequency, 2.8 kHz bandwidth, USB mode only
- Maximum bandwidth 100Hz
- There is only one Queensland allocation on 5364 kHz (tx and rx, suppressed carrier), located in a very remote area – Normanton in the Gulf of Carpentaria.