Long distance communication

Human to human communication has been occurring for...I'm not sure exactly how long to be honest so I'll say a long time. It's sometimes done well and often not however verbal, and no-verbal, communication is something that we all do in some form and whether it fails to occur effectively or not it happens between people every day, face to face and over great distances.

As technology advanced we began to find new ways to communicate with each other from further away; Think smoke and drum signals, carrier pigeon, books, letters, notes and messages, Semaphore signalling with flags or lights, Morse-code and telegraph, radio, wired, cell and satellite telephone and internet. There's others but you get the point. All have been useful in particular applications and I'd say most of us have used one or more of these methods.

One of the methods I have used and relied upon in my life is radio communication. It has been a very important aspect and lifeline in certain situations and without it...Well the consequences of not having the ability to communicate would have been dire.

As an avid four-wheel driver and one who likes to get away from civilisation into the wilderness radio communication is something I put a bit of effort into - It offers peace of mind first and foremost, the ability to communicate in an emergency and a little light entertainment when travelling in convoy. When off-roading there's many reasons one should have their communications wired tight.

When in convoy it provides vehicle to vehicle contact and when in the rough stuff it can be used to help mitigate risk. An example is a particularly technical section of track, maybe a very steep and rutted track - Having a spotter outside the vehicle with a hand-held UHF radio communicating back to the driver can help place wheels in the right spot and avoid a lot of strife. In fact, this is one of the main reasons I carry UHF on-board.

When thinking of UHF radio one must put a lot of thought into the type of antenna one chooses...The bigger is better ethos is sure to bring a person unstuck because bigger isn't necessarily better at all. Let me explain.

Antenna's all have different properties and depending on their make-up will perform very differently; Incorrect antenna choice could render a UHF radio useless - They are application-specific and a great deal of care needs to be taken with their selection and fitment to the vehicle. What works well on wide-open flat land will not work so well in mountainous terrain for instance, and that's where people go wrong.

Antenna's are usually measured or rated by way of gain. Basically gain is how effectively the antenna converts the input into radio waves and transmits them outwardly; It works in reverse too. This is often measured, mostly simply, in decibels-isotropic, dBi for short.

High dBi

Keep in mind I'm talking about four wheel drives in this case but essentially the dBi of a very tall antenna will be higher than a shorter one. Let's say a long 120 centimetre antenna is mounted to the vehicle, it is likely to have a dBi of 9 dBi which is considered high. This translates to the antenna being able to push out a signal over greater distance but the signal is flat [think ripples on the surface of a pond]. The signal pushes outwardly and to quite great distances - Perfect for wide open flat or even terrain.

But get that same antenna into hilly or mountainous terrain and it becomes ineffective. That flat signal will be blocked by terrain-features and will be redirected as the angle of the vehicle changes. Imagine a vehicle travelling up a steep incline. The antenna will be pushing the signal straight up and over the top! Add in some forest and valleys and you're in trouble.

Low dBi

This is where the low dBi antenna comes into play. I'm talking about antenna's of around 3 dBi which are very much shorter, sometimes only 10-15 centimetres as opposed to the 120 centimetres of the 9 dBi variant.

These antenna's send out the signal in a more general field, think a bubble or sphere, around the antenna. This sphere of transmission reaches out in every direction including to high peaks and down within valleys. It is the most effective way to ensure constant communication between vehicles and personnel in hilly terrain.

Living in Australia means there's a lot of generally flat open ground and we have our share of mountains or hilly terrain also, it's diverse. This means that I carry both a high-gain and low-gain antenna and switch them as required, terrain-dependant. If only one is possible I'd split the difference and opt for the 6 dBi option but I use a 2.1 dBi on an every day basis and 9 dBi for open country which screws on over the same fitting.

Mounting

Where the antenna is mounted also has an effect on its performance - Ideally it would be mounted in the centre of the vehicle right on the roof to avoid anything that might impede the signal but that's not always practical. There's a myriad of brackets and means of mounting them though so there's always a suitable option for all vehicles.

I mount mine on my bull-bar on a manufacturer-welded-on tag for that exact purpose. Sure, the vehicle will block a little of the signal heading backwards but I've never had an issue. The general rule is to mount it where the signal will be least effected though.

It's this high-gain/low-gain antenna situation that's responsible for many operators mounting two antennas to the vehicle. Some will run two radios in the cabin or a switch system to ensure the most appropriate is used at any given point. I've never run with two or more, but it certainly makes things a little easier.

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When travelling remotely having effective communications can be critical. Australia is a vast and rather inhospitable place with extreme temperatures, immense distances between civilisation and a lot of dangerous things in between. Being connected is very important. Of course a UHF radio is rarely going to have the range to reach help when one is way out back, even using the repeater stations, but it can certainly come in handy.

When in the outback or wilderness areas I always suggest a combination of various communications. Mobile phones will be useless in most places although I still have one. A UHF radio of course, and definitely a satellite phone which will bounce a signal to literally anywhere using satellite's and of course an EPIRB emergency beacon for when things go really bad. Some take HF radios which provide long-range communications without the need for repeaters although they can be very expensive and are bulky too.

All of this equipment is available for hire when travelling remotely so there's really little excuse to be without the right communication when out in the wilderness. Knowing how to use it is pretty important, what station to use and not use and so on. It could save a life, yours or someone else's, and can provide a little entertainment if travelling in convoy.