Strapline: HF Communication
Headline: HF MOD delivering capability
Byline: Kym Bergmann
Australia has a long history of expertise in high frequency (HF) radio communication, going back to the early 1930s. This came about because of the country’s vast distances and sparse population – combined with the advantage that HF (which is between 3 and 30Mhz) has over frequencies further up the radio band: great range. This, in turn, is a consequence of atmospheric physics and the fact that the ionosphere surrounding the planet refracts HF signals.
The ionosphere is a shell of charged particles that varies in height above the earth’s surface from 80kms to about 1,000kms and is made up of a number of layers. It is in a state of constant flux, leading to a degree of unpredictability about exactly how radio signals are propagated. HF – or more colloquially short wave – broadcasts sometimes travel enormous distances because after refraction they bounce off the surface of the earth and are then refracted again – sometimes for multiple skips. On other occasions signals are curtailed because of adverse ionospheric conditions.
An early user of HF radio in Australia was the Royal Flying Doctor Service, which needed a form of long range communication able to cover the huge distances of the Outback. Pioneering work was conducted by Alfred Traeger, who developed the famous pedal radio – actually a pedal generator – able to transmit morse code messages and later voice traffic as well.
In the military domain a by-product of indigenous HF expertise was the development of the Jindalee over-the-horizon-radar, which is based on exactly the ionospheric properties described above. Work on Jindalee started in earnest in the early 1970s and today is an under-publicised success story, allowing the monitoring of vast amounts of air and sea traffic to the north east of Australia. The official indications of the range of the radar are likely to be an understatement given the signal skip or bounce phenomenon referred to earlier – which applies not only to signals being transmitted but also those being reflected back.
It is therefore no surprise that the ADF continues to make extensive use of HF communications under JP 2043 – better known as HF MOD. After several years of difficulty meeting all of the very ambitious contracted targets, prime contractor Boeing Australia – having signed the contract in 1997 – has delivered a system that will continue to support deployed forces for many years to come. At the time Defence needed to consolidate 11 different HF sites for three services into a single joint operation – able to fulfill requirements for beyond line-of-site strategic and tactical communications.
The system has nodes in Darwin, Townsville, the Riverina and at Northwest Cape. Control is exercised from a facility in the Canberra region at HMAS Harman with a back up site in the same general area. It has been fully operational from the middle of 2009, after the delivery of the “core” system in 2005. The scope of the project was technically ambitious because of the level of system automation that was required and was software intensive – always an area of risk.
This consolidation of HF communications has taken place despite the huge investment – which will eventually total billions of dollars – in satellite technology, especially via the mega-project JP 2008. Because satellite systems typically operate in the UHF band, they can handle vastly more data than lower bandwidth HF – giving them a tremendous advantage in the transmission of capacity-hungry things such as live video.
Asked to comment on whether HF MOD is in danger of becoming something of an anachronism in an age of satellites, a Defence spokesperson explained:
“JP2043 replaced aging and obsolete Navy and RAAF systems and introduced a modern, tri-service capability. High frequency systems provide an ability to communicate across large distances without the use of repeaters or satellites because of the various modes of propagation. This ability is a significant advantage for the Australian Defence Force as it enables reliable long-haul communications to be established where satellite coverage is not available or where denial of service is a threat. While there has been a significant increase in the use of satellite communications by the ADF, high frequency communications will continue to be a part of ADF communication infrastructure providing long distance strategic communications support to the war fighter. A number of other nations are now reconsidering their use of HF communications and have expressed interest in the JP2043 solution.”
That is not to say that HF MOD has been cheap – it has not. Though more limited in its scope than originally envisaged, cumulative expenditure on the system runs into hundreds of millions of dollars. Asked to quantify the benefits, Defence responded:
“The high frequency communications system developed under JP2043 provides improved quality of voice services and messaging data speeds, improved reliability of service and improved probability of connection for all high frequency capable platforms. Increased automation has improved connection speed and signal integrity and has reduced the number of operators required. Platforms that are fitted with automatic link establishment (ALE) capable radios – major surface ships and front line air assets – also gain the additional benefit of automation of connectivity to the fixed network which further improves connection speed and signal integrity.
“Under the old system it might take operators up to 10 to 15 minutes to engineer a circuit for each voice or data call. The old system required elaborate communications plans to be manually developed and calls had to be constantly monitored by operators to ensure they didn’t drop out. The JP2043 system produces automated communications plans (which are based on an analysis of the ionosphere and identify the best frequencies over each 24 hours of the period planned) against any date range and platform entered by an operator, e.g. for the conduct of exercises. For ALE platforms JP2043 constantly monitors the network and instantly selects the optimal circuit for each voice or data call. The JP2043 system has also improved data speeds – about 10 fold for a standard defence message. It does not support email.”
Another benefit of HF is that it is far less expensive to use than satellite time, though now that Australia is a member of the US-led WGS constellation this advantage might be diminished. Nevertheless, for low bandwidth and non-urgent messaging, HF is likely to remain an attractive option commercially. Additionally, HF MOD is an Australian only system and so issues of sovereignty over its use will never arise.
As well as prime contractor Boeing, a number of other companies have been involved. According to Defence, Ebor Computing developed a prototype for the signal enhancement element (known as Nullarbor) of JP2043. The roll out of Nullarbor across the network is the last remaining element of JP2043. A number of companies were also involved as subcontractors to Boeing. These include Thiess (facilities), BAE Systems Australia (filters and messaging software), Ericsson (switches), Radio Frequency Systems (antennas), Optus (fibre and microwave links), Rockwell (transmitters and receivers) and Dell (servers and computers).
No equipment was sourced from Boeing itself. Boeing Australia Limited (now Boeing Defence Australia) developed the majority of the mission system software and the Signal Processing Switching System (SPSS), the intelligent switch that identifies and categorises modulation types and switches accordingly.
Regarding the source of HF radios, Defence says the work completed under the project scope included utilisation and integration of various commercial off-the-shelf transmitter, receiver and transceivers from companies such as: Rockwell Collins, Hagenuk, Harris and CUBIC. Essentially, all radios in the HF spectrum will work with JP2043 – and any future high frequency capable platforms will be able to connect with it.
As well as developing and delivering the system, Boeing continues to support it – and in addition to matters of maintenance in February 2011 the company signed a services contract with the Commonwealth. This is to provide engineering support with the aim of keeping HF MOD at the leading edge of technology.
