Offroading or 4WDing is undoubtedly one of the most iconic Australian pastimes, whether it’s a solo weekday excursion or a weekend getaway with friends or family. No matter how you explore the great outdoors, a reliable means of communication is non-negotiable.
UHF Antennas offer a mode of communication that comes in handy for group coordination and for requesting help during emergencies. Ultra High-Frequency antennas ensure that no matter where you are, you can communicate with family and emergency services as required.
As any 4×4 veteran will tell you, you should never leave for an offroad excursion without a reliable radio and a UHF antenna to support it. If you’re keen on learning more about UHF Antennas, continue reading below to learn more.
What are UHF Antennas?
Ultra High Frequency (UHF) Antennas are components that you can install onto your offroading vehicle to allow you to transmit or receive radio signals from fellow offroaders and other people. These connect with others through a frequency of 477MHz at a range that depends on several factors.
These UHF Antennas generally come in two forms – in a portable, handheld version via a UHF radio or a fixed, in-vehicle unit with an external antenna. The in-vehicle form offers a much larger range and practically unlimited run time at the expense of higher costs and the inability to use the radio if you’re away from your vehicle or it is turned off.
What is the Simplex Mode for UHF Antennas?
The simplex mode means that the UHF antennas are directly communicating with each other on the same frequency or channel. Either side takes turns transmitting and receiving signals without the use of repeaters or having other units in between.
In some cases, only specific channels can be used for simplex mode communication to help streamline communication in the event of an emergency.
What is the Duplex Mode for UHF Antennas?
The Duplex mode is a setting that allows UHF radios and antennas to transmit signals on one channel while receiving through a different channel. This means that if you were receiving signals through channel 1, you would be transmitting on a channel different to that, such as channel 2.
Why Do I Need a UHF Antenna?
The most important use of a UHF Antenna comes during emergencies, such as when you have lost your way through a remote area, you need help fixing your vehicle, or when you or someone in the group has gotten into an accident and requires medical attention.
A UHF Antenna (and unit) inside your offroading vehicle will give you a medium of communication that will come in handy when travelling in areas that are outside the range of cellular towers. Since UHF antennas continue working even if your devices have no reception, it is crucial when travelling in groups or in a convoy.
UHF antennas are used around the world but are especially important in Australia, where our terrain is varied and dangerous and reception in the outback is spotty at best. A UHF Antenna is the prime example of safety equipment you need to have but hope never to need.
What to Consider When Installing a UHF Antenna
Much like any other component or accessory for your vehicle, there are things that need to be taken into consideration. These factors include the specifications of the UHF antenna itself, and driving conditions, among others.
Gain
Measuring aerial gain or, simply gain, is usually done in dBd or dBi. High Gain (6-9 dBi) is great for long-distance communication on open plains or the highway where the terrain is flat. These will give you a long line of sight, but any obstruction will create issues.
Medium Gain (3-6 dBi), on the other hand, is for those who want to find a middle ground between distance and terrain. Medium Gain antennas are usually considered “all-rounders”.
Lastly, the Low Unity Gain, simply referred to as Low Gain, is particularly common in cities and mountainous areas. These have a very low range but a round output range that will bounce over hills or buildings as high as sixty stories.
Mount
The mounting position of the UHF antenna needs to be considered. With the vast amount of vehicle and UHF antenna combinations, there may be cases in which certain antennas may not properly mount on certain vehicles, if at all. And even if the antennas can be mounted on a vehicle, it may not be ideal enough for the antenna to receive and transmit signals as intended.
Height
The height is directly affected by both the type of antenna (based on the dBi), as well as the terrain you are driving in. If you drive mostly in the city and only ever go offroading on the weekends, then a very long antenna might not be suitable, as the city often has low clearances. On the other hand, if you have a high-gain unit, installing a taller antenna will help the signal go over certain instructions.
Flexibility
This is an area where medium-gain UHF antennas generally shine. Since these antennas do not specialise in long lines of sight or short wide-ranging output, the “all-rounder” medium gain antennas become an excellent choice for those who drive in different locations with varying weather and environmental conditions.
Driving Conditions
This is where the gain of the UHF antenna becomes significantly important. The driving conditions or the weather affect the signal transmission and reception. This means antennas easily disrupted by obstructions (such as high-gain antennas) may not perform well under such conditions.
Location
Another aspect where the gain of the UHF antenna becomes very important. If you drive your vehicle somewhere in the city or a mountainous region, then it’s best to get a Low Gain antenna. If you live or drive in a wide-open area, then the Long Gain antennas would be best. If you’re unsure or your location varies, it might be best to get the “all-rounder” medium gain antennas or speak to a local auto parts specialist.
Cable Length
Remember that you will be mounting the UHF antenna on your vehicle, not your house. This means you have to ensure that there is just enough cable running so your vehicle won’t be drowning in excess cables. In some cases, you will be forced to sacrifice the antenna height to get a shorter cable length, depending on the specific model.
Brands
Similar to other products in any field, certain brands have objective strengths and weaknesses in their performance. In addition, different brands will have varying depths of customer support, warranty or spare parts availability. The brand of your vehicle or radio may even have compatibility issues with the UHF antenna you choose, so make sure you consider this when making a decision.
What is a Multi-Antenna System?
A Multi-Antenna System (MMO) uses more than one antenna to allow simultaneous transmission and reception of signals with little to no disturbance. This kind of system generally sees the use of special components to keep the system running as smoothly as single antenna systems.
This kind of system is useful for increasing the channel capacity since it will send signals independently from different antennas.
Can I Install a UHF Antenna Myself?
Yes, you can install a UHF antenna yourself, but only if you have had prior experience installing or removing UHF antennas. If you do not and are unsure how to proceed with the installation, it is highly recommended that you seek the service of professionals to install it.
Where Can I Get a Good UHF Antenna?
Autobarn, Supercheap Auto and Repco are some of the leading names in auto parts and accessories, and all carry a large range of antennas. Make sure to speak to one of their staff in-store to help choose an antenna model and have it professionally installed.
Related Questions
Does the Length of a UHF Antenna Matter?
Yes, the length of a UHF antenna matters, especially for UHF antennas that require a direct line of sight, like high-gain antennas. Remember, radio signals may be easily disrupted if obstructed, so consider the type of UHF antenna, your specific needs, and its relative length.
Is a Higher dB Antenna Better?
No, a higher dB antenna isn’t automatically better; it depends on where and how it is used. For example, a high-gain UHF antenna will not necessarily be better than a low-gain antenna in a crowded urban environment. A medium gain antenna will also not always be better than low gain antennas.
How Do I Increase my UHF Reception?
While there isn’t any definitive way of increasing the reception of your UHF antenna, there are ways to optimise the transmission and reception of signals. Try testing different mounting positions and orientations of the antenna onto your vehicle to see which has the best reception.
Can I Use Multiple UHF Antennas?
Yes, you can use multiple UHF antennas with a multi-antenna system, which allows for more than one UHF antenna to be installed and used on your vehicle. However, remember that this is not always necessary and that swapping or moving your antenna will be enough to give you the boost in reception that you need.
