Yagi antenna is the product of the collaborative effort in the early part of the 1900s between its inventors, Hidetsugu Yagi and Shintaro Uda. During those times, they are still attending the Tohoku Imperial University.
Nowadays we are using an abundant variety of directional types of antenna, but so far Yagi remains the most popular and most sought after. Some people would fondly refer to them instead as “beam” antennas.
Do you know the reason why Yagi antennas achieve so much gain?
It is because they direct the majority of all its signals to just only one direction as opposed to dispersing it all around in a 360-degree circle. Their rods and single element whips on boats and cars are all qualified omnidirectional, which means they do a 360-degree job.
The taller or higher the altitude of these antennas is, for a given frequency, the more gain there is on the horizon, where there is a strong need for it.
But what is the gain?
This is the term being used when you need to measure out decibels (dB) and determine the level of effectiveness of an antenna in a particular plane or a given direction.
In other words, this refers to the unit of measure of an intensified signal where it is needed or where it is wanted since antennas, technically, are not capable of creating gain.
Antennas are designed in such a way that they can manage the power in the direction they are needed, and for this reason, be able to tone down unwanted directions.
Mounting Your Antenna
Your available feeder cable length will determine your ideal mount spot. As for the cable length considerations, this can be addressed instead at a later time. Otherwise, roof edge, window sill, fence, balcony railing, wall, the horizontal or vertical pipe can be taken advantage of for this purpose.
It is also acceptable to have an inside-attic installation provided that there is no metal present in the roof in which the signal will need to penetrate. It is quite normal for concrete and wood to be invisible to RF signals, but under frequencies ranging from 824 to 894 MHz, the gain itself is likely to go down a bit.
Where to Point Your Antenna
The frontage of yagi antennas should be directed towards the target direction, repeater tower, or cell site. Or in some cases, it should be directed instead towards other users.
Sometimes also, things are better off when there is a good amount of knowledge about the target location itself, together with the use of a map and compass. There is a good possibility that you’d be able to locate it if it is also sending out signals that are directed towards you.
When you rotate your Yagi antenna, you’d easily find the direction of the strongest signal source. Gradually rotate your antenna, and pause every 10 degrees. At this point, you may jot down signal levels. Take note of the decline and the peak positions, and eventually, you’d figure when and where you should be tightening your mounting bolts.