HF set to take on new millennium

In the new millennium, when it seems everyone has a mobile phone and is networked and connected 24 hours a day, seven days a week, what is happening to the more traditional forms of communications such as HF radio?

What advances have been made and how do they compare with the latest in technology?

While the basics of radio communications have not changed, the expectations of the end user have driven a number of innovations.

The first innovation to change the way we use HF radios was selective calling (Selcall). The ability to identify specific radios with a four digit ID was the breakthrough that enabled a number of other changes.

Transmission of GPS information, the transmission of short text messages and remote diagnostics followed shortly after. The development of telephone interconnects allowed for direct dialling of telephones from the radio.

It also gave the ability to contact a radio from office, home or mobile telephone. In fact, most radio scheds from the large networks are no longer conducted directly from the radio but from a mobile phone through a telephone interconnect.

The development of methods to overcome the difficulties associated with correct frequency selection for the time of day and the distance needed over which to communicate, was the next step forward. For a long time, network managers had used frequency calling schedules, where everybody changed frequency at a specified time, to overcome changes in the ionosphere throughout the day.

This, however, did not address the frequency selection problems, where some stations in a network were required to operate over a few hundred kilometres and other stations needed to operate over thousands of kilometres.

These difficulties are now overcome by beacon calls and automatic link establishment (ALE). Both methods require the radios to scan a number of programmed frequencies that would allow operation over varying distances and times.

In a beacon call, the operator will manually select one of his programmed frequencies and send a beacon signal to the station he wants to contact. If the frequency is suitable for communications, the receiving station will automatically stop scanning and send a revertive signal back to the transmitting station. If no revertive signal, or a very weak signal, is received, the operator will then select another frequency to attempt communications.

ALE operates on the same principles, however, the beacon calls are sent automatically and the radio maintains a memory of the link quality for different times and distances.

When an operator attempts a call on an ALE network, the radio will use this memory to automatically select a suitable frequency to contact the distant station. International standards (FED-STD-1045 and MIL-STD-188-141) have been established to ensure compatibility between different brands of radios when conducting ALE operations.

Around the time these changes were occurring, the majority of the world was becoming comfortable with the use of email. People wanted to take advantage of this capability when they operated in remote areas. Satellite communications offered a solution that was not always cost effective, so HF equipment manufacturers provided a solution using the free-to-air nature of radio waves.

Modern HF data systems employ the latest digital signal processing (DSP) techniques and are specifically designed for HF operation. With full connectivity to the internet for email, modern HF data systems are transparent.

Emails are sent and received via the user’s own familiar email client software, such as MS Outlook or Lotus notes. This form of communication has become immensely popular with United Nations organisations and NGOs operating worldwide.

This market quickly expanded to include defence. Martin Johnson, business development manager for Barrett Communications, says:

“Operating in remote locations while conducting peacekeeping and disaster relief duties, defence force personnel had exposure to HF commercial, off-the-shelf equipment. They recognised the significant savings that can be achieved buying COTS equipment, so supply of equipment for the military quickly became a major market for us.”

The blending of supply to both military and commercial users has also provided benefits to the commercial user. HF transceivers have become lighter and more compact. Current consumption has been reduced and much of the equipment has been manufactured to meet military specifications for immersion, temperature, shock and vibration.

Defence, government and NGOs had the networks take full advantage of the HF innovations. They had HF internet gateways, telephone interconnects and vehicle tracking systems. Recreational or small business HF users needed a service provider to give them the same advantages.

Recreational and commercial networks were quickly established to give them those capabilities.

Sail Mail is an example of one global network offering HF email for cruising yachts. Other networks operating in Australia today provide a number of additional services, including message handling, weather and road condition reports, emergency assistance, telephone calls, GPS positioning, SMS and short text email service.

So what does the future hold for HF operation and manufacturing, when the next generation has never known life without personalised ringtones.

According to Martin:

“Communications providers are commercial enterprises. They base their infrastructure where there is the potential for profit. There will always be the recreational traveller with a sense of adventure or the soldier or aid worker with an operational requirement to communicate in regions where there is no communications infrastructure.”

This company is constantly researching and developing innovations to ensure equipment capabilities meet the latest user expectations.

The soon to be released wireless handsets and changes to the current Selcall capabilities are just two examples of this.

The recent acquisition of Q-MAC Electronics and the construction of a new, purpose-built manufacturing plant in Bibra Lake, attest to the companyÂ’s commitment to the future of HF communications in Australia.