Many people want a “radio” for their 4x4 vehicle, but when you question the reason for wanting a radio you invariably hear “well in case I get lost or my vehicle breaks!” My response is always well who are you planning on taking to?

Why do you want a radio? For emergency purposes, inter vehicle driving, contact with your home or just to receive news and weather information.

What is available on the market?
27 Mhz or CB Radios. These radios have an output power of 4 watts and are AM radios thus giving you a range of between three and eight kilometers. Greater ranges can be achieved depending on your location, but realistically 5km range is average. Most radios on the market are old and at the end of their life. The cost of a new CB radio including installation would be approximately R1600.

29 Mhz Radios or ski boat radios. These are by far the most popular radios in the offroad market and this system is promoted my most clubs. They have the same power and range as CB radios but have the advantage of being professional in the sense that a single channel is licenced and the band is not a “chatter band”. The most popular channels for offroading are channel 1 29.7100 Mhz and channel 14 29.8725 Mhz . These radios have the added disadvantage of having squelch controls and if the squelch is turned too far, the radio receiver is desensitized thus reducing your range to a few hundred meters. Approximate cost R1800 installed.

Commercial FM radios these are VHF (midband and highband) or UHF radios. These radios have an output power of 25 Watts and the mode is FM. Communications are crystal clear, the squelch is preset and on the basic models there are only ON/OFF and volume controls and so they are very easy to use. Your range is realistically 20km on VHF highband and up to 35km on midband. Midband is less effected by the terrain whereas range on highband and UHF is almost line of site. Mountains and valleys will restrict communication considerably on highband and UHF. Approximate cost R3500 installed.

Note: A specific channel is issued to you and you will only be able to communicate with the people in your group who have the same channels you. Channels are preset and the chance of finding someone else on your channel are 1 in 1 500 000.

HF or SSB radios. These are the systems that the long distance trucks use as well as game lodges, missionaries, etc. These radios have an output power of 100 watts and operate in the SSB or single sideband mode and are the radios that radio amateurs use to talk around the world. Range is around the world BUT the range is determined by the frequency, time of day and sun spot activity and so some experience is necessary to select the correct channel for the said conditions. Conditions during the day are fairly predictable but early morning and late afternoon communications can be problematic.
Commercial HF radios are channelised and the authorities will issue you with a set of channels that you can use. Once again you will only be able to talk to someone who is using one of your radios. You will also require an antenna tuner if you want to use the system optimally. Approximate cost R20 000 per radio (and tuner).

Satellite Communications. Satphones as they are called are great and the adverts look good. You can use your satphone day or night and call any number in the world with the only disadvantage being the cost of the calls. Airtime is sold on a “pay as you go” basis and is sold in US Dollars, the more time you buy the cheaper the rate but you will be paying between R19 and R30 per minute. The “pay as you go” cards don’t expire as with celphones but the smallest denomination in usually $100. Satphones can be rented at R1000 per week or purchased for R15 000.

Airband, Marine and Amateur Radios. These are strictly out of bounds and the use of this equipment will result is heavy fines and possible arrest.

Emergency Purposes
By emergency communications we mean the ability to contact outside help. Here you are limited to satellite phones or HF radio as the chance of picking up another station on any of the other systems is remote.

Picture a typical scenario, you are stuck in the middle of Namibia and the nearest town is 150km away. Assuming that you manage to contact someone on the radio, what are you going to tell them. Who must they contact for you? How can the recovery vehicle find you? See advanced planning.

Inter vehicle
Here you can use any of the systems, with the most cost effective being 29 Mhz with a body mounted antenna. The old adage of “rather buy a cheap radio and an expensive antenna than the other way around” still stands.

Handheld radios of all types have very limited ranges as the antennas are a compromise (size), the signal is electromagnetic and the vehicle’s body is metal thus the body of the vehicle shields the signal. Another problem is recharging of the handheld units or in some cases the consumption of penlight batteries. Also it is illegal to use a handheld radio in a vehicle whilst driving with the same fines as for cellular phone use.

Reception of short wave
Being able to receive short wave means that you have a window to the world. The BBC, Deutche Welle and Radio Nederland transmit news 24 hours a day and having a short wave receiver is a great companion. Marine stations also broadcast weather bulletins that can be received on these radios. Sony and Grundig make small, portable short wave receivers which receive the full short wave band, medium wave and FM. Medium wave or AM as it is marked on some radios also receives the BBC and Voice of America as well as a number of local radio station. Night time reception on medium wave can be very good and reception of distant stations is possible.

Advanced planning
Planning your communications in advance of your trip is essential as the bureaucratic systems can delay issueing of licences for months and failure to have the required licence in neighbouring countries can result in your radio being confiscated.

It is also important to let your backup know where you are and what the contact numbers are of the local garage or recovery service. On a single vehicle adventure (which we do not advocate) it is important to stop at the local lodge or garage and introduce yourself and obtain their contact numbers which in turn you will pass on to your backup (usually a friend or family back home). In an emergency you can contact them and they will then be able to contact the local lodge or garage and summon help.

Learning how to read a GPS is essential as in some cases your coordinates are all that will guide your rescuers to your stranded vehicle.

Regulations
Licences are required to operate communications equipment in every country in the world.

South Africa
ICASA
Private Bad X1
Marlboro
2063

Tips for better communications

Antennas
There is no point in spending thousands of Rands on the top of the line transceiver if you cannot hear anyone because it has not been properly installed.

There are basically three types of antennas on the market, ie. Magnetic antennas, glass mount antennas and body mount antennas.

Magnetic antennas have the advantage of being easy to remove and install but have a number of distinct disadvantages. With some vehicles having aluminium bodies the antennas don’t “stick”, secondly even a small amount of dust will result in the typical coffee cup ring on the paintwork and on an extended trip this ring will begin to rust. Also the antenna cable will have to be fed into the vehicle through the door or window and will result in dust entering the vehicle and the chance of damaging the antenna cable is also increased.

The only real application would be in a hire vehicle in which you cannot drill holes.

Glass mount antennas are neat, easy to mount and do not require holes. These antennas are the least effective of all.

Body mount antennas are the way to go. If installed properly the vehicle will not rust around the antenna and the antenna’s earthing system will be excellent. The antenna cable is mounted permanently and is therefore less susceptible to damage friction and or damage by passengers.

In general the higher the gain an antenna has the better (see diagram) your range over flat ground will be improved, but this will be a slight disadvantage in hilly terrain.

The antenna should generally be mounted as high as possible. The location of the antenna on the vehicle will also effect the radiation pattern of the antenna and this must be kept in mind when you are trying to contact the furthest station

Electrical
The radio, no matter which type should always be connected directly to the battery via a fuse, and not to any convenient wire under the dashboard. By doing this, you will isolate any interference from the vehicle’s electrical system which could be misinterpreted as poor reception. A filter can be wired between the power supply and the transceiver to stop the interference.

The reason for putting a fuse at the battery is that if a short circuit were to occur the fuse would blow before the wires got hot and caused a fire. Spare fuses should be carried and a piece of tin foil from a cigarette box must not be treated as a fuse.

Positioning of the Radio
The actual transceiver should be positioned so that you can see it without taking your eyes off the road and definitely should be not positioned in full sunlight (on the dashboard). If you are going to be crossing rivers consideration should be given to keeping the unit out of the anticipated water.

General
With all these systems it is essential that the equipment is installed professionally and correctly and the perception that the system can be installed by yourself is generally incorrect. All antennas have to be adjusted to resonate at the correct frequency and if this is done incorrectly your transceiver can malfunction and require repair from a electronic technician.

If an error is made in the wiring of the system a fire can occur with disastrous results.

Buy only well known brands as these systems are supported internationally and you should be able to obtain spares and repairs from their agents in all countries.

Remember that the most important component in the whole system is the antenna, DON’T go for the best looking ---go for what works.

Maintenance
Once you have your radio properly set up, there are a few simple ways to keep it working in top order.

Prevent water from entering your antenna cables by sealing them with silicone prior to any trips. Once water has got into the cable corrosion will occur and the antenna system will stop working efficiently and the cables will have to be replaced.

Check the power cables and antenna cables are not getting pinched under plastic linings and in doors.

Check your antenna to make sure that it is still secure on the vehicle, you will be amazed what vibration can do to locking nuts. Check to see that the whip has not been bent or broken, if it has been broken replace it immediately and get your local two way radio dealer to set up the antenna before you use it as this will prevent you burning out your radio.

Before a trip check that the equipment works, clean all fuse holders and fill them with non conductive silicone grease. Clean all corrosion off of your battery and smear battery terminals with Bosch battery grease, this will prevent corrosion build up.

Remember that when transmitting your transceiver draws a lot of current from your battery. A few hours of chatter from the camp will result in you not being able to start your vehicle in the morning and possibly a LONG walk to get help. If you are going to have an extended discussion on the radio start the motor every 20 minutes and let it run for 5 minutes or so as this will recharge the battery.

For more information on communication systems for recreation, business or commercial applications phone:

GRS TWO WAY RADIO
Cape Town
Tel:(021) 913-1262
Fax:(021) 913-2709