Frequently Asked Questions


Q: What radio must I buy?
The answer to this question depends on a number of things that need to be considered. Firstly, who do you want to talk to? As odd as this may sound it is a valid question.

Buying a radio that is not compatible with radios owned by people you want to talk to will leave you out there in a world of silence. Check what your fellow club members are using and check what your mates have. This will help you decide what type of radio you will need to buy to communicate with your fellow 4x4 club members and friends.

If there is an intention to do a lot of traveling outside of our borders, then 29MHz radios are highly recommended as they are classified as CB radios and can be used cross border a lot easier than VHF sets that will require commercial licensing.

Q: Are 29MHz radios still a valid option?
Definitely yes! 29MHz radios have their place. They are relatively cheap, safe, reliable, and a number of clubs and groups still choose to use 29MHz sets over the newer high powered VHF sets. The number of supplies of these sets has declined in recent years, but they are still available.

29MHz sets are also less of a problem in our neighbouring countries as they are defined as CB radios and are easier to use as a visitor.

Q: Must I buy a VHF radio?
It is the “new technology”, but no you don’t have to. Actually VHF is not that new and has been around as long as 27MHz CB and 29MHz radio. It is new to the 4x4 community only because ORRA has been legally licensed for this purpose for a relatively short period of time.

VHF does have benefits including higher transmit powers and good immunity to atmospheric and manmade electrical noise, but their installation and setup is a bit more complicated and needs to be done correctly to ensure safe operation.

Q: Can I modify a 27MHz CB radio for 29MHz ORRA use?
Although this is technically possible it is not practical or recommended. This modification requires expensive test equipment and workshop facilities to perform and as such the costs of this conversion make it prohibitively expensive. Rather dispose of your 27MHzCB set and use the money towards a new 29MHz set.

Q: Why is a VHF radio so much more expensive than a 29MHz set?
29MHz sets use simple internal circuits, are on lower frequencies, transmit with low power, and use AM modulation. VHF sets on the other hand use more sophisticated internal circuits, are high frequency (and hence have higher stability), transmit with higher powers, and use FM modulation.
All these differences in technologies incorporated into a VHF FM mobile make them significantly more expensive to manufacture.

Q: Can any VHF radio be modified / programmed for ORRA use?
No. Although most modern day high band VHF radios can be set up or programmed to work in the ORRA configuration, there is a very good chance that older radios will not be compatible with our setup. Before purchasing a second hand older radio always check that it will work for you prior to paying for it. And remember you need to have a valid user authority for this radio even if it is an old unit bought second hand.

Q: Why do I have to have a radio license for my VHF radio?
All radio transmitting equipment used within South Africa is required to be licensed by the end user with ICASA as per the Telecommunications Act.

The one exception to this statement is the UHF License Free radio frequencies and equipment that is available for low power short range personal and business communications. These radios are available at 4x4 shops, online vendors, farm co-ops, and some hardware stores. They include professional ranges and even the cheap "blister pack" radios usually sold as a pair. However even these are ICASA type approved for this specific service.

Coming back to the VHF licensing question. The VHF frequencies allocated to ORRA by ICASA are commercial radio frequencies. As such they need to be legally licensed for use by the end user.

However, it is almost impossible, and somewhat impractical, for a private individual to license a commercial frequency for their private recreational use for a number of reasons including administration, cost, compatibility, and liability, amongst others.

As a service to the members of recognized member clubs and organizations ORRA facilitates this process with ICASA. The frequencies in question are licensed in the name of ORRA, and then with ICASA's approval ORRA issues the user authority cards and documentation to its members, thus making it legal for you as an individual to make use of commercial radio frequencies for your 4x4 and club activities.

Also, by doing it through a single organization, we ensure that everyone within that organization is then licensed for the same frequencies and channels. This allows for compatibility between different members and different clubs.

In terms of the Radio Act, it is illegal for a registered radio dealer to supply commercial radio equipment to an individual unless they can prove they are legally licensed to own and operate said equipment. So, technically an individual cannot just go out and purchase radio equipment for their own use. On the ORRA website are listed all the registered dealers that support ORRA members by supplying equipment in the correct and appropriate legal way.

Some points to remember here once again are -

  • the frequencies are shared and as such you need to be aware that your communication is not private and confidential
  • because the frequencies are shared, you need to respect other users on the channel
  • the licensing process is only legal for South Africa. You cannot use your VHF equipment, be it hand held or mobile, outside of the borders of SA with your ORRA license / user authority. It has no standing currently outside the country.

ORRA frequencies are all in the high band VHF section of the spectrum (approx. 146mhz-174mhz) and as such low band VHF radios (approx. 50mhz -80mhz) cannot be used for our applications. Digital modulation and trunk radio system units are not compatible with our configurations at all. Marine VHF and airband VHF radios can generally not be set up to work on the ORRA frequencies due to modulation type and band coverage issues. It is also technical illegal to attempt to use these radios for applications that they were not designed (and registered) for.

Q: What are tones?
Conventional two way radios all have a function called squelch. This control allows one to mute the speaker on the radio until such time as a received signal is present. When the radio detects the presence of an incoming RF signal of a certain minimum level (as set by the squelch control) the squelch circuit in the radio unmutes the audio circuit and the incoming received signal is heard. This allows the radio to remain silent until such time as signals are being received. Squelch is found on all 29MHz and VHF radios.

The limitation to this conventional system of squelch is that any incoming RF signal will unmute the speaker and allow the audio through no matter where that RF comes from.

Many years ago manufacturers developed a more advanced squelch system to allow multiple users on the same frequency. Known as CTCSS (Continuous Tone Coded Squelch System) it introduces a continuous sub-audible tone into the transmission from a radio.

In the receiver on the other end, the signal is received and the squelch opens up as before, but now an additional step takes place, the radio is also set up to look for this sub-audible tone and only if this tone is present and it matches a specific one that it is programmed to look for, will the speaker unmute and the audio be heard.

This feature is transparent to the end user as these tones are filtered out of the signal as part of the process and are never heard by the operator.

The end result of this is that multiple users can now share a common frequency. Given that most radios spend 80%-90% of their time in standby and not transmitting, a frequency can be successfully used more efficiently by a number of different user groups, each set up with a different set of CTCSS tones. Only members within each group can hear that group’s transmissions.

The ORRA frequencies we have been allocated are no exception to this and are shared amongst many users. Around the country various other commercial organizations (security companies, trucking companies, farming communities, etc.) have perfectly legally been allocated the same operating frequencies as us.

Starting in October 2011 ORRA will be rolling out a new revised programming configuration for radios that will result in a new set of predefined channel numbers. This new configuration will include CTCSS tones on all our channels to allow reduced levels of interference and irritation from outsiders.

Note – the use of tones is purely a “comfort and convenience” feature. It does not offer confidential or private radio channels as anyone listening in on a radio with no tones set up will hear everything being broadcast by everybody on that channel. So, be careful what you say, and follow proper voice procedures!

Q: How do we get 8 radio channels when we are licensed for only 3 radio frequencies in the VHF band?

Originally ORRA was allocated one VHF frequency at around 150 MHz, a little while later this was supplemented with another frequency at around 160 MHz .These two frequencies are the channels know, up until the end of 2011, as ORRA ch 1 and ORRA ch 2.

In the latter part of 2011 a 3rd frequency, also up in the 160 MHz range was allocated to ORRA by ICASA.

Along the way there have also been numerous complaints received regarding interference from other users on our frequencies making the use of VHF radios unpleasant especially in heavily built up urban areas. When radios are not in use by members, but still on in their vehicles, people got sick and tired of hearing commercial traffic from other users.

This resulted in the following issues that the Sub-Committee had to look at -
  1. Antenna matching over a wide range of VHF frequencies.
  2. Ongoing interference on the frequencies we are licensed for.

In numerous meeting of the Technical Sub-Committee held in 2011, the following solutions were debated, discussed, and finally agreed on -

1) Channel numbering change -

As the 2nd and 3rd ORRA channels were relatively close together, it would be beneficial from an antenna tuning point of view to get all members to move to these two frequencies for their regular communications. This would allow them to tune their antennas for maximum efficiency on these two frequencies.

However, when they then used the original ORRA ch 1 frequency, their antenna would no longer be well tuned, compromising the efficiency of the transmission.

From this a new channel numbering system was agreed to -

The old ORRA 2 would become the new ORRA 1

The new 3rd frequency would become the new ORRA 2

Members would then be advised to use these new frequencies as their main operating options.

The old ORRA 1 would be relegated to the status of a backup frequency for "other" use, because now the antennas will not be ideal for operation on 150 MHz, having theoretically been tuned for the 160 MHz area of the VHF band.

But, this is only half the story......

2) Introduction of CTCSS sub-audible tone systems.

Also part of the process was the decision to introduce continuous tone coded squelch systems (CTCSS) as standard for ORRA. This will not be explained in detail here as it is well explained elsewhere in the FAQ section on the web site. Suffice to say that by introducing this, we were able to stem the interference from other users that was irritating members when they are driving around with their radios on.

And finally, as we all know that most radio channels are dormant for 80-90% of the time, the introduction of CTCSS allowed us to create more than one "channel" on a given frequency.

This because although all radios are on the same frequency, if say two groups were using different CTCSS tones, then individual groups would only receive comms from others in their group with the same tone. As long as the two groups were not on air all the time, this could work and allow 2 sets of users on the same frequency.

As a result of the above, the following configuration of 8 channels were worked out and set up as the new standard -

New ORRA 1 - Old ORRA 2 frequency with tone A
New ORRA 2 - Old ORRA 3 frequency with tone A
New ORRA 3 - Old ORRA 2 frequency with tone B
New ORRA 4 - Old ORRA 3 frequency with tone B
New ORRA 5 - Old ORRA 1 frequency with tone A
New ORRA 6 - Old ORRA 1 frequency with tone B
New ORRA 7 - Old ORRA 1 frequency with no tones
New ORRA 8 - Old ORRA 2 frequency with no tones
New ORRA 9 - New ORRA frequency with no tones

The first 6 channels are the 3 ORRA frequencies with 2 different sets of tones to mute out all other users except ORRA members using the same setup.

Channel 7 + 8 are the original ORRA channels 1 and 2, with no tones. This was included as a compatibility option so you can chat to members with radios not yet converted to the new standard.

Really you only need a 6 channel radio and you will have the maximum flexibility available to you from the 3 radio frequencies allocated to ORRA.

If you have a radio capable of 8 channels or more then you benefit from the new flexibility as well as maintaining compatibility with radios not yet converted to the new standard.

This is how the 8 channel setup was derived from only 3 radio frequencies.

This may not an ideal solution for everyone, but it was deemed to be a good compromise solution that could be used going into the future.


Q: What antenna must I buy / what is the best antenna?
When buying an antenna for your vehicle it is important to purchase one that is specifically designed to operate on the frequency of operation that you intend to use. The type of antenna and the mounting configuration needs to all be considered at the time of purchase.

The best antenna for a given application is one that meets the following requirements:
  1. Is designed for the operating frequency of the radio
  2. Meets you budget
  3. Can be correctly and properly mounted onto your vehicle
  4. Can be tuned correctly once mounted
  5. Is aesthetically acceptable to the vehicle owner / driver

If you stick to reputable brand names when it comes to antennas you will not have a problem finding one for your application.

Q: Where is the best place to mount my antenna?
For best results and effective transmission and reception, an antenna needs to be mounted as high up on the vehicle as possible. However, this is somewhat of a contradiction for us off-road types as it is also vulnerable to damage in the bush. As a result mounting location is usually a compromise. The mounting location depends on a number of things, including:
  1. What type of base fitting the antenna has
  2. Are you ready to drill holes in the bodywork of the vehicle
  3. Where does the vehicle park (how high will the antenna stand up once mounted)
  4. What other accessories are on the vehicle (rooftop tents etc.)

All these need to be taken into consideration before deciding where to mount your new antenna. Also chat to other club members in your club and get their input from their experiences before making your decision.

Q: Why must my radio’s antenna be “tuned”?
The length of an antenna is directly linked to its operating frequency and to the mounting configuration. As commercial antennas are all made for a range of operating frequencies, any antenna needs to be trimmed and tuned for the required operating frequencies as part of its initial installation.

See further details on this subject in the antenna section of the ORRA website.

Q: What is SWR, and why is it important?
The SWR (Standing Wave Ratio) measurement, when done correctly, is a quick and simple way of checking to see that the antenna system is correctly matched to the radio.

Although it is a very theoretical and technical subject, the SWR instrument is basically indicating how much of the generated RF power is being effectively radiated out into space by the antenna system. The function of the instrument is to indicate the ratio of RF power being fed into the antenna versus the amount being reflected back into the transmitter. This reflected power can do damage to the transmitter electronics and should be kept to a minimum at all times.

When the SWR is at its lowest reading, it means the antenna is successfully radiating all or most of the generated RF power, and little or none is being reflected back into the radio transmitter.

Q: Can my old 27MHz antenna be used for 29MHz operation?
Although it is possible to modify a 27MHz antenna to work on 29MHz, this is not recommended. Purchase the correct antenna for the radio you want to use, and get it tuned properly for the application.

Q: Can my old 29MHz antenna be used for VHF?
No. A 29MHz antenna is not designed to work on VHF and will damage the radio if any attempt is made to use it for VHF transmission.


Q: Can I install my own radio?
Yes you can. There are however some basic principles that need to be adhered to in the process, so if you are not experienced in this ask for help from fellow club members in the know. Alternatively, you can have your radio installed by a professional installer for a fee.

Either way, make sure the installation is done properly and tested by someone who knows what they are doing before putting the radio into regular use.

Q: Where do I install my radio in my vehicle?
The answer to this question is dependent on a number of criteria:
  1. The type of radio and it’s physical construction
  2. The available mounting locations
  3. Is the vehicle owner prepared to drill holes in the interior trim of the vehicle?
  4. Access of the power lead and the antenna lead to the proposed radio location
No matter what you decide the following are very important points to be considered:
  1. The mounting location must be safe and away from the drivers area of movement during normal driving operations and not interfere with any of the driver controls
  2. The mounting location must not interfere with the deployment of any and all air bags within the vehicle
  3. The mounting location must be secure. The radio cannot fly around in the passenger compartment during off road driving or an accident
Q: Can I install my own antenna?
Yes you can. Once again there are some basic principles that need to be adhered to in the process, so if you are not experienced in this ask for help from fellow club members in the know.

You will need to know how to use a soldering iron and solder, and be prepared to make holes in your vehicles body work. You will also need to be aware of the location of wiring harnesses and other electrical and electronic system within your vehicle body work before starting the installation as your actions could damage these vehicle components if you are not careful.

Refer to the antenna section of the ORRA web site for further details on antennas.

Q: What do I need to “tune” my radio’s antenna?
The simplest instrument used to tune an antenna once it is installed is an SWR meter. See the “What is SWR” question here in these FAQ’s, or look under the Antenna section of the ORRA web site for further details.

Q: Why is the power supply from the battery so important?
All radio transmitters need a stable source of power to operate reliably. For this reason it is important to have a proper power lead between the radio and the vehicle battery. As a minimum, the (+) positive power lead needs to be fused a s close to the battery as possible. On VHF radios there is also sometimes a fuse in the (-) negative power lead. If your radio is fitted with this do not remove it but install it as directed in the owner’s handbook.

A good power lead for the radio will be fed directly from the battery and will not be connected into the vehicle fuse box or the vehicle cigarette lighter etc. Although some non- permanent installations may make use of a temporary power supply like cigarette lighter fly leads this it is not recommended for long term use.

Q: Will ORRA help me install my radio?
No. ORRA administers the legal side of the 4x4 fraternity’s radio needs but does not have the facilities to offer an installation or repair service. Please refer to the dealer listing on this website to find a radio dealer near you to assist with this request.


Q: Why are other people on our frequency?
There is no such thing as “our” frequency. The radio frequencies we use in ORRA are allocated to us on a shared basis with other users around the country. We do not have exclusive use of these frequencies and it is perfectly normal to find other users on all our allocated frequencies.

We share these frequencies with these other users and it is for this reason that we in ORRA need to uphold a high level of voice procedures and professionalism when using our radios.

Q: What are voice procedures?
Voice procedure is a term used to describe the correct procedure and process of talking on a radio. Good voice procedure ensures efficient use of the frequency in getting your message across and also ensures that the communication takes place in an orderly, respectful, and professional way. Good voice procedures also allow others to know who is on the channel.

Voice procedures include all of the following points :
  1. Use your call sign on a regular basis to allow yourself to be identified.
  2. Wait and listen first before you talk, only one person can talk at a time as the system does not operate like a telephone conversation.
  3. Speak in a slow and clear voice across the microphone face and not directly into it.
  4. Do not hold the microphone to close to your mouth; this will cause distortion in the transmitted audio.
  5. Keep your transmission short and to the point.
  6. From time to time pause before replying in a conversation to give others the opportunity to join the conversation.

Q: What am I not allowed to say over the radio?
No foul, derogatory, blasphemous or insulting language is allowed to be used on the air. No prejudice on the ground of race, religion, sexual orientation, political affiliations or cultural grouping is allowed during radio transmissions.