ob_hd.jpg (28086 bytes)Abstract
ob_m.gif (2146 bytes)ost of Australia's population is focused around the East coast cities of Sydney (in New South Wales), Melbourne (in Victoria) and Brisbane (in Queensland), around Adelaide (in South Australia), around Perth (in Western Australia) and Darwin (in the Northern Territory), and to a lesser extent Hobart (in Tasmania). Once you reach the interior, or Outback Australia, population is sparse and the region is desolate, other areas such as the Top-End are subject to weather extremes.

Traveling through these Outback and Frontier regions of Australia is a challenge, these areas are isolated, services are sparse, and your well-being often depends upon your own capabilities and any contact that you may be able to maintain with the outside world. You must take a comprehensive tool-kit, spare tires, tire-repair kits, medical supplies, additional food, water and fuel, and maps.

Amateur Radio, the Royal Flying Doctor Service, Telstra Land Mobile Radphone services, Penta Comstat, the Australian National Four Wheel Drive Association, and for the more lucrative, the Satellite telephone networks, are the communication lifelines for the Outback traveler.

There are no cell-phone services. CB radio (27MHz AM/SSB) and UHF CB (475 MHz FM) are only suitable for inter-vehicle operation. Despite the occasional UHF CB repeater or the occasional phone cell, these services cannot be relied upon for long-haul emergency communication.

What you need is type-approved powerful HF SSB radios in the 100-400W PeP range. HF Radio Telephone (Radphone) and voice operation have historically been, and still are, the most easily accessible and affordable communication services for the outback traveler. It is the need for these links and the ability to operate them which make outback travelling an interesting pastime for the radio enthusiast.

This article describes travel through Cape York and the type of radio equipment that can be used to keep in contact with friends and the outside world.

ob_map.gif (8296 bytes)Figure 1 - Radio service centres (Blue Telstra, Red National 4WD Association, Green RFDS)

Cape York
My most recent trip into the outback as to Cape York. It has some very remote population centers, the larger ones like Bamaga, Weipa and Cook Town have access afforded by sea because the land routes are largely unnavigable during the Wet season.

The Top End of Australia has two seasons: Wet and Dry. So much water falls during the Wet season, and combined with vast subterranean aquifers, that the rivers and creeks of Cape York keep flowing on through the Dry season. These rivers and creeks provide for the excitement of many and frequent deep water-crossings for the avid four wheel driver.

The Wet season causes the Cape to be unnavigable by land, which helps ensure that this North-Eastern frontier of Australia remains a difficult environment hostile to the European concept of land use. It is so inaccessible, hot, and humid during the Wet season that its European population is largely migratory. This population has become tourist dependant because much of the former European land use has failed and land has been handed back to the Aboriginal Communities. The township of Weipa is a noticeable exception because it is a Company town which was established to support the huge open-cut Bauxite mining operation.

The following services can be used by a licensee who holds a Remote Outpost or Land mobile license. The Telstra Radphone services can also be used by registered ships. To use service the operator is required to obtain a suitable type-approved HF mobile from a supplier, a license (callsign) and to registister with the communication body.

The Royal Flying Doctor Service of Australia (RFDS), with its "Mantle of Safety" slogan is probably the most famous in the world for its use of HF radio. The RFDS has a network of HF stations scattered around Outback Australia, providing communications and medical services. There are 13 remote RFDS bases which can fly doctors and nurses to accident victims with a response time of 90 minutes or less. The whole Outback is serviced by the combination of these bases.

The Center for Distant Education provides schooling through School Of The Air (SOTA) on some of the RFDS channels during the day. Hearing children communicate with their teacher and sing on SSB is quite an interesting and seemingly unusual event. You can hear them sign on in the morning in synchronicity as the lack of carrier permits multiple responses with no heterodyning interference.

Some RFDS centres can provide Radio Telephone services, which are patched into the regular Public Switched Telephone Network (PSTN) provided by our National telephone provider Telstra and other third party Carriers. The RFDS system employs an in-band dual-tone (880Hz and 1320Hz) which triggers an emergency alarm used to alert an operator or awake the after-hours duty attendant, usually a doctor, who will proceed to attend to a possible medical emergency. This is an interesting system. The two tones are required to be accurate in their frequency offset, as the difference mixing product (440Hz) is used to trigger the alarm - making it basically immune from any incremental tuning between the SSB transmitter and receiver - very clever!

The Telstra Radphone service, as the name suggests, provides HF phone-patch. The new Telstra system employs DSP processing, split transmit and receive frequencies, and antenna isolation, which ensures some measure of privacy. The same in-band dual tone (840Hz and 1380Hz) is used to alert the out of hours duty operator, but in this case it is not considered an emergency, which has led to confusion when inter-operating between the RFDS and Telstra Radphone services. The East Coast Telstra stations are unmanned and remotely controlled from Brisbane. This includes Townsville Radio, Sydney Radio (which was closed down and assigned to Brisbane) and Brisbane Radio transceivers. SELCAL numbers can be assigned to the newer mobile radio equipment so automatic/semi-automatic link/call establishment is possible, but there are still a lot of older radios which rely upon Voice Call which requires a duty operator to monitor the call channels and announce traffic lists. This is the principle mode employed by the Maritime Mobile operators and the older radios which are usually not fitted with SELCAL.

If you operate in the evening, when propagation is favourable on the lower frequencies, you often join ship-to-shore traffic and must wait for an opportunity to slot your callsign in to check your traffic list or originate your phone call. It seems that bases point their antennas out to sea, and during the day you often manage to contact a station which is using an antenna pointing the wrong way. It is not unusual for the operator to request you to count down from 10 - so they can swing the beam!
I find that the operators are fascinated when they learn of your location. They often ask for weather reports and what it is like etc.. On several occasions during daytime operation, particularly when traffic is light, it is not unknown for the operator to rag-chew. Some Telstra operators hold Amateur Radio licenses and quickly learn of other ham operators from their radio protocol. On several of these occasions we have exchanged the other callsigns (and it doesn't count toward any DX award!).
Penta Comstat is a smaller company providing a service, which I have never used. It provides HF email, weather reports and Land and Maritime Mobile phone patches.

The total of these HF services, provided by Australian organizations, were an essential communication link for Outback homesteaders. The progressive installation of telephone services in outlying homesteads has seen that the majority of users of these HF services, apart from SOTA, are now Land and Maritime Mobile operators. Land Mobile operators dominate during the day, particularly in the tourist seasons, whilst during the night the operators tend to be Maritime Mobile. Many Korean and Japanese shipping companies use the Telstra HF Radphone services to phone home, and often tie up the voice call channels for hours at a time, making it difficult for Land Mobile stations to call in and check for traffic. (This is very convenient for ships, last time I checked it was a $4.50 connect fee and $3.50 per minute for calls anywhere in the Australia/New Zealand area and International calls were not overtly expensive.)

Several Amateur Radio operators provide the Traveller's net on 14.112MHz. Your friends can check in and pass messages and travelers check in giving their locations and estimated destinations. Concern is raised if people miss their check-ins after several days, so their last known position is reported to the authorities and notifiable persons. This is a good service for those Amateurs that don't hold Mobile Outpost licenses and for their relatives as the people concerned may be contacted by phone before the scheduled net time, but I find that the queues can be quite long.

Operation on 30m whilst mobile is quite fruitful in Australia as many operators now have equipment which includes the WARC bands. 40m is usually crowded and consumed by nets and those more interested in short-haul communications. 20m is very favourable at noon as Western Australia and South Australia are easily worked from the Centre and the Cape.

Mobile Equipment
Since the distances are vast you need to have frequency agile equipment to match propagation conditions. As an Outback traveler you rely on these HF services for emergency, rather than rag-chewing, so the equipment must be able to transceive on various frequencies in different bands so you are assured that some service is available at the times when you may need it most.
On my first Outback trip I took a home-brew helical with taps for all Amateur bands 80m and above. Before the next trip, because some friends suffered a medical emergency, I modified the whip to support RFDS and Telstra Radphone frequencies and obtained equipment and a License so I could operate on these frequencies.

On my recent trip to Cape York I took my 9' whip and a modified Sailor ATU which I use for 160m (and upwards) mobile. On the first trip I carried a home-brew telescopic 10m vertical, which I used on 160m (and up to 20m). On all the trips I carried sufficient wire to erect a 160m half-wave dipole, which is fed by open-wire feeder, a 1:1 current-mode balun, a 1:4 current-mode balun and a L-match ATU.

I modified a Mullard No 7 (LF/HF) ATU- which is in a nice green die cast box. The LF series inductor was removed and I rewired the switch which is ganged with the tuning capacitor shaft so it switches 2000pF of capacitance in parallel with the variable 2000pF tuning capacitor, essentially doubling the range of this capacitor so I could feed the 10m vertical directly on 160m. Half of the 180 degrees of the capacitor travel varies the capacitance from 20pF to 2000pF and the other half of the 180 degrees travel varies it from 2000 - 4000pF. I also added a double-throw switch to the ATU so the capacitor can be switched between the transmitter and antenna end of the variable inductor. You can tune long wires or high-resistance antennas when the capacitor is connected to the antenna end or short very low-resistance antennas when the capacitor is connected to the transmitter end. (Don't forget that even though short antennas are low resistance they are high-reactance antennas and will have a very high (reactive) voltage at the base - so don't touch them!)

This ATU is simple to tune because it carries an on-board current meter which measures the input current which is easily peaked. I was able to work from Broken Hill to New Zealand using the 10m vertical with the ATU and one elevated radial on 160m! But when I bush camp near a stream and it's daylight I usually throw the wire antenna up through the trees. I have found that the trees nearest a stream are usually the best. Some of my best contacts were made when the wire antenna was run parallel to the water flow and only a few feet above the ground! I have worked New Zealand from the Flinder's ranges in South Australia using the dipole almost directly above the stream which was running North-South.

My wire antenna was made by splitting approximately 40 m of figure-eight flex (zip cord) and feeding the two pieces at the centre with "dog-and-bone" 450-ohm open-wire feeder. This 160m dipole also works very effectively on 80m, 40m, 30m and 20m with suitable tuning adjustments. You can also string up half of it if you only want to work 80m and above. I have used it in other configurations in the desert because good trees are scarce. It works when you string it from the 10m vertical or from a 6' tree with the remote ends held just above the ground using rope as an insulator and screw-drivers as the support stakes! On one occasion I ran 20m along the rail of the upper level of a Motel and tied the other end to the water tap in the bathroom and drove the 4WD up to the front door so I could connect the feeder and spoke with my mates using 160m. On the last trip I suffered an interesting antenna modification, I accidentally broke off and left about 10m or so of one leg in a tree, after which the ATU would tune 160m and 30m on the same setting - most convenient!

The 30m band was always good and was used as a backup when 160m didn't make the distance. If you attempt to work-over from the tropics, propagation doesn't seem to be too good on the lower frequencies.

The Outback has little noise so you can hear almost as effectively on the mobile helical as you can on the stationary dipole. Travelling North of the Tropic of Capricorn 25S onto 11S is most frustrating; you can hear everyone but they have extreme trouble hearing you when operating 160m. This is probably caused by the Earth's magnetosphere. We are still exploring this phenomenon by observing the operators that take their 160m equipment across the top end. The Cape is also farther West than the rest of the East coast and suffers a later sunset as a result. It can be up to two hours after the East Coast sunset before 160m signals a detectable. I was also suffering European DX QRM on 80m and 40m - which I found most annoying!

I have often found that it is an advantage to be able to move the mobile rather than just rely on the base camp antenna, and when you are forced to camp in a caravan park only vertical antennas are practical. I have worked 160m mobile from Weipa (12.6S) to Melbourne just by taking my 4WD and reversing it down a boat ramp almost into the waters of the Gulf of Carpentaria - this is long haul! I have also been able to contact Tasmania and Brisbane, whilst up on the Cape. I spoke with VK2DPS (in Moree) and VK2ABN (on the south coast) whilst mobile between Cunnamula and Nyngan on the way home so don't write 160m off as a suitable communication band when travelling over these sort of distances.

160m is my favorite band, and I have other mobile contacts whilst operating the shorter distances to Melbourne (450km), Orange (250km), Sydney (250km), Tasmania (700km)and Moree (625km) during my drive home from work; the conversations are short however, because it only takes me between 15 to 25 minutes to get home!

Now, here are just a few of the photos I took of my equipment and during the trip.

Photo 1 The central radio console - just finished construction the day I left. This wooden console replaced the flimsy plastic console.
Photo 2 The home-brew HF helical whip.
Photo 3 The HF stainless whip, Sailor ATU and home-brew HF helical.
Photo 4 A close-up inside the Sailor ATU
Photo 5 The Variometer, switching relays and capacitors inside the Sailor ATU.
Photo 6 The vehicle driving down Dulhunty river to cross the Old-Telegraph road.
Photo 7 Crossing the Dulhunty River - Old Telegraph Road.
Photo 8 Crossing the Wenlock River.
Photo 9 Push bikers on the Cape (6 weeks round-trip Cairns to Top and back).

Hope you enjoyed the trip! Ralph Holland, VK1BRH vk1brh@dynamite.com.au -30-
Biography of VK1BRH

References and Bibliography:

Service Mobile TX (if split) Mobile RX
Cairns VJN 2020  
Mt Isa VJI 2020  
Charleville VJJ 2020  
Broken Hill VJC 2020  
Port Headland VKL 2280  
Carnavon VJT 2280  
Meekatharra VKJ 2280  
Darwin VJY 2360  
Derby VJB 2792  
VKJ 4010  
VKL 4030  
VJT 4045  
VJC 4055  
Melbourne VIM 4074 4366
(Ex Sydney radio) VIS 4077 4369
Brisbane Radio VIB 4098 4390
Darwin Radio VID 4107 4399
Townsville VIT 4119 4411
Perth VIP 4143 4435
Penta Comstat VZX 4335 4354
VJJ 4980  
VJI 5110  
VJN 5145  
VJB 5300  
VJY 5300  
VIS 6218 6519
VZX 6221 6522
VJJ 6845  
VKJ 6880  
VJT 6890  
VJB 6945  
VKL 6960  
VJY 7975  
VIS 8198 8722
VIP 8210 8734
VID 8225 8749
VIM 8225 8749
VIT 8234 8767
VIB 8237 8761
VIT 8243 8767
VIB 8707 8707
Traffic Lists on hour 8707 8707
VZX 8713 8713
VIS 12236 13083
VIP 12305 13152
VID 12308 13155
VIB 12314 13161
VID 12314 13161
VIM 12314 13161
VIS 12314 13161
VIT 12314 13161
VIT 12320 13167
VZX 12329 13175
Travelers Net 14114  
VIS 16363 17245
VIB 16387 17269
VID 16387 17269
VIM 16387 17269
VIP 16387 17269
VIS 16387 17269
VIT 16387 17269
VIP 16393 17245
VIT 16393 17275
VID 16423 17305
VZX 16483 17365
VIS 22006 22702
VIP 22033 22729
VZX 22126 22865

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Last modified: March 23, 2005