We figured this is the right time for us to talk about the UHF antenna. Beyond the aesthetics, finding the right type of antenna involves some thought as to what you need it for.
For example, varying dBi ratings in aerials can also be used for different terrains. This dBi rating could, to a certain extent, measure the size and thickness of the aerial you want to obtain.
Gone are the days when almost every 4X4 you come across seemed to have a black strip of fibreglass hanging off from the bullbar? Sometimes they look like a fishing rod that is emptied of its copper cable trappings.
Back in the day, they seemed to be the all-season aerial you could get. Although they operate on a lower frequency, mainly 27MHz, it was predominantly one-size-fits-all with them.
With the arrival and testing and experimentation of UHF broadcasts (around 477 MHz), a myriad of aerials intended for use in incessantly changing contexts became accessible. The use of UHF antenna offers better bandwidth (data and voice quality).
But since they work at a higher frequency, it renders the radio waves to pierce through to the ionosphere. If that happens they will make their way out into space sans the usual ‘bounce back’ that is normally observed with VHF (27MHz).
What is dBi in light of radio signals?
Picture an invisible doughnut hovering just right above your 4-wheel drive aerial. Except for maybe the small hole, the doughnut is massive, and it doesn’t have flour or cinnamon.
This doughnut would be stretched vertically or horizontally depending on the aerial dBi rating — a higher dBi signifies a flatter but more expansive doughnut but with a lower dBi which signifies that it is going to be higher albeit skinnier.
What are the Different Aerials?
For this UHF radio guide, assessing aerial gain is usually performed in dBd or dBi for consistency. It makes it easier for us to understand. Besides, the majority of aerials are promoted with just the dBi grade.
The term dBi means “decibels in relation to an isotropic radiator,” where the number is really what matters to us. Ponder upon dBi in aerials, picture that in your mind as a lantern with a focusable beam, together with your 5W UHF unit as either the LED or bulb while your aerial will act as the focusing ring.
The torch will continue to deliver 5W, but if you intensify the beam to around say 9 dBi and it travels a long distance.
Only a small section on the other side of the camp is highlighted, but it will keep you from seeing your feet. You can now have a view of the next door’s camp if you have the focus ring in another way to say, for instance, 3 dBi. To put it briefly, this is the dBi.
Gain: 6 to 9 dBi
These aerials are usually made with a broom handle and are frequently very long. They’re perfect for use for long-distance travel on open fields as well as on roads with flat ground.
With its long and wide doughnut, it’ll toss far and wide with line-of-sight. However, by putting a house, hill, or woodland along its path, you are likely to have communication difficulties.
Medium Gain: 3-6 dBi
Traditionally, they come with wrappings of a copper wire or the 3-feet stainless-steel stick highlighted in the middle by a ‘pigs tail‘. At any point within this dBi range can provide a good balance of spectrum and line-of-sight hindrances.
This range’s signal output would be like a doughnut in the middle – not even that flat, but just not perfectly round either.
0-3 dBi is a low unity gain.
These are more commonly used in urban areas but are taken advantage of as well in the alpine/mountainous regions. The part of the name Unity essentially signifies that the aerial path emanates uniformly across all directions.
They’re usually stubby and short and normally come with a thermal coating. This type of aerial will consistently push a signal across trees, mountains, houses, and a host of other similar obstructions – sad to say that it will be at the cost of range.
They come with an almost perfectly round doughnut, and it will rebound as high as it can throw signals horizontally along 60-story buildings or across highlands.
So, depending on where you are heading with your four-wheeling and what you need from your UHF antenna, make this guide as your reference to achieve the best reception imaginable when you’re on the highways.