Do High Gain Antennas Make A Difference?
| Reuben Howe
Aerials and Antennas are relatively simple bits of tech. At their most basic, they are a bit of metal connected to a coaxial cable while the more advanced aerials use mains power amplification, clever engineering or even magnetism to enhance reception!
One of the main ways you will see an antenna set itself apart is by claiming to be "High Gain". Don't fall into the trap of thinking all "High Gain" antenna are the same, though! As we will discover, not all high gain antenna provide the same range, signal strength and design so paying attention to the details of high gain aerials is vital when making a purchase.
What is High Gain in Antennas and Aerials?
Firstly, the term itself "High Gain" is essentially a statement over the "Strength" of an aerial. There are some key caveats to this strength, but overall a high gain aerial has more power and range than a non-gain aerial.
On the surface that sounds objectively better! But as I said, there are some drawbacks to this increased oomph...
How High Gain Changes Aerial Reception
While high gain antenna do have more range and therefore more chance at reception than their un-amplified counterparts, the extension comes as a cost. Consider the diagram below:
In this image we can see the aerial in this campervan doesn't receive signal from the tower across the valley.
Now, if the caravan uses a high gain aerial:
Both Diagrams are representative only and are exaggerated to demonstrate the effect of high gain. Not all "high gain" aerials will narrow the reception as much as is displayed.
As you can see, the aerial can connect to the relay tower! The difference between the normal and high gain aerial is the extension of reception range. However, the "shape" of the reception is also entirely different. This is the effect of high gain. Gain changes the direction and distribution of volume which the aerial is able to receive from. In this way, a high gain aerial helped the camper "reach" far enough by stretching the signal reception from a uniform sphere into a longer, more directional shape.
Some of you may have already worked out why High Gain aerials differ so much already, and it is because of this effect of changing the "shape" of the reception. Some aerials may be so long range and so directional that simply bashing them with your hand is enough to align them (or interrupt a stable transmission!) while other aerials use a smaller amount of gain to maintain a more even coverage around the antenna.
How Much Gain is "High Gain"?
When discussing high gain aerials it is clear that not all gained aerials will behave identically. Fortunately, gain has an established unit of measurement. "dBi" or "Decibel Isotropic Antenna" is used to show the extent to which an antenna is being boosted by gain. Most aerials will have between 1 - 3 dBi minimum, to give you a baseline standard. "High Gain" aerials then range between 5dBi for un-amplified aerials all the way to 30dBi for amplified antenna!
The higher the gain, the more directional and longer-range your scan. Some devices manage to counter the narrow scope by using magnetic connections to conductive objects to broaden the aera, but in general it is same to assume that higher gain = more directional.
When to Use High Gain Antenna
The key thing to understand is that high gain, especially when amplified by a power supply and reaching in excess of 20dBi, is highly situational. If you are a hotel owner wanting to add a TV to their lobby or a bar manager wanting to show the football then a high gain aerial is best, as the establishment is stationary and you can securely set up the aerial with the extended range pointed at the transmitter, just like the campervan above.
However, if you are travelling and the nearest transmitter is in an unknown direction, then a more uniform scan might be helpful!
Finally, if you are very close to a transmitter then the high gain antenna will pick up the signals just the same as a normal one, as the broadcast tower is in range of both equally. That means you don't always need to splash out on a high gain aerial if you are sure your reception is good enough without.
Experiment and Research
The only way to work out which strength and gain of aerial is useful for a specific situation is to try them out. While antennas do have estimated ranges, these can vary based on natural phenomena, interference, local geography and even the placement of the aerial itself within a home or establishment.
High gain is a powerful boost for many aerials, and certainly make a difference to your maximum reception range, but at the cost of a more directional and potentially higher-energy set up.
Explore a selection of low and high gain aerials from aerial experts August International all available directly through us at iDaffodil. If you need any help, don't hesitate to contact our support teams from our Contact Us page.