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The ArrowLog Periodic Antennas, or Where to Put Your Arrow

Written by Alex Baker
Expert Review by Sadruddin Currimbhoy
May. 19th, 2021

Pointy and Effective at Getting Better Cell Signal, it's The Arrow, by Bolton

Quiver with anxiety when you think of where to put The Arrow? Pointing it in the right direction and letting it fly may sound trite, but what if we told you it could drastically improve your cellular signal?

That’s probably the last thing you expected us to say.

Jokes aside, we’re not talking about a traditional arrow. Instead, let’s chat about The Arrow, the latest log periodic antenna by Bolton Technical. It can give you cell signal other directional antennas couldn’t dream of.

But how?

What is a Log Periodic Antenna?

A log-periodic antenna - hyphen strictly optional - is known by many names: LPDA (short for log-periodic dipole array), log-periodic dipole antenna, log-periodic aerial, or just a log-periodic array. They have a simple job: to operate over a wide band of radio frequencies. What these frequencies bandwidths are vary based on the type of log periodic antenna you buy.

They’re more common than you might think. You’ve probably noticed log periodic antennas in passing all your life, sitting atop suburban and rural rooftops, poking out on apartment balconies. They likely let your mother watch the latest episode of M*A*S*H. Traditionally, log periodic antennas have been used for analog television, which was the dominant style until digital eclipsed and replaced it in the recent past. Even still, they remain used in many areas, and, as a quick search for a TV antenna will show you, they continue to dominate that market.

The reason for this is simple: they have excellent range and can cover a wide range of broadband frequencies. Their directivity allows them to have a narrower focus than their cousins the yagi antenna, which gives them increased power over their brethren. Properly installed, they will work in fringe areas yagis just can’t. But their value as a TV antenna is only the tip of the iceberg.

That’s where The Arrow comes in. See, lots of people have cell phones now. Saying that is like saying lots of people have grass on their lawn - it’s almost assumed at this point that any human being you see walking the streets owns at least one phone, even if it’s a Ron Swanson style flip phone you only carry around to keep your wife happy. And, what do cell phones need to function, other than some sort of battery? Why, cellular signal. Which happens to be a type of radio wave.

Now that cell phones are an essential part of most people’s lives, these cellular radio waves are constantly around us. This has led to a massive flood of other cellular-compatible devices, and that will only continue as time marches on.

What if you have weak cellular signal, though? What if you live in the sticks, or your house is designed like a bunker and none can enter? Maybe you don’t WANT to live with cellular signal invisibly all around you, and only want it in certain areas? What then?

Enter The Arrow - even more heroic than the TV character.

The Arrow Log Periodic Antenna, a Cellular LPDA for Any Building

This section is going to be entirely focused on the benefits of The Arrow log periodic antenna, and will keep the confusing technical talk to a minimum. If you’re interested in the nuts and bolts of The Arrow, keep scrolling. If you just want to know how to get better cell signal, you’re in the right place.

The Arrow will receive all kinds of cellular signal (including 4G, LTE, 3G, 2G signals across all major carriers, including AT&T, Verizon, T-Mobile, Sprint, Rogers, Bell, Telus, and more). Its directional nature means it can target a single cell tower at a time, allowing for very specific tuning of any system you use.

The Arrow is an extremely effective antenna to pair with any cell phone signal booster or cellular hotspot, providing consistent cellular or WiFi in a building. It won’t work without being attached to some sort of system, as it requires the system as a power source.

If you’ve never heard of a cell phone signal booster, they’re also called amplifiers or repeaters. They work rather like a WiFi router: they need a source of signal, and, once obtained, they rebroadcast it within a confined space. The Arrow is tailor made to be the outside antenna used in one of these systems, able to provide +12 dBi gain to the signal propagated by the booster.

The Arrow can be used in both urban and rural areas. It has over 5 miles of range and can reach faraway towers, and can bring even the most stubborn cellular signal indoors. It also is great in urban areas, which have a very different problem: oversaturation of noise. The Arrow cuts right through the urban radio noise directly to a designated cell tower, and provide amazingly clear signal indoors.

In short, this thing is a great performer if you need cell signal, and is probably Bolton Technical’s most versatile offering. But how is this great performance achieved?

How Do Log Periodic Antennas Work?

If you’re reading this section, get ready for some technical jargon. We recommend taking a deep breath.

All set? Good. Let’s get started.

Log periodic antennas (hereafter referred to as ‘LPDA’ or ‘LPDAs’) normally consist of half-wave dipole elements each consisting of a pair of metal rods positioned along a support boom lying along the antenna axis. The spacing of these elements are what allow for the tuning of the frequency range of the LPDA - meaning, The Arrow is finely tuned in such a way as to pick up cellular frequencies between the 698-2700 MHz frequencies. Other LPDA antennas focus on VHF, UHF, WiFi, and other wavelengths in the high frequency GHz spectrum.

LPDAs are contrasted with EMC antennas, which operate electromagnetically, and array antennas, which are big, complicated arrays of numerous antennas that can both transmit and receive. LPDAs are significantly more diverse in their usage - they can operate off of standard power, and can be installed just about anywhere at not too great of a cost.

A key element of LPDAs is a focus on antenna gain (measured in dBi). While a yagi or omni antenna focuses on bringing in signal within relatively close environs, the LPDA can work adequately in fringe conditions. This is accomplished with a relatively focused radiation pattern, at a roughly 30 degree beamwidth. The Arrow provides up to +12dBi, a significantly higher number than the max gain of a cellular yagi.

A radiation pattern with such high gain and wide bandwidth is achieved by creating, more or less, a three-element yagi antenna. The directors and reflectors are in reversed positions on The Arrow, with the shorter pieces acting as the directors and the longer ones toward the back as reflectors. The design of the Arrow provide polarization along the back ratio. The directors and reflectors are far less obvious and ostentatious than on a traditional LPDA rig.

Every element of an LPDA is a driven element, connected electrically to the feedline. This feedline - usually coaxial cable, but sometimes twin-lead or ladder line - zig zags between the dipole elements. Certain LPDAs are known as log-periodic zig zag antennas because they replace the dipoles with the feedline itself, but this is not true of The Arrow.

What Kind of Log Periodic Antenna is The Arrow?

The Arrow is an upright planar LPDA, which is a size-reduced LPDA. This is what gives it its signature “arrow” shaped design (get it? “The Arrow”), and allows us to make silly quiver, bow, and arrow related puns.

So you know, it’s actually easier to aim The Arrow than a typical LPDA, as most LPDAs are placed horizontally. It is even possible to sight directly down the transmission line of The Arrow to aim it, which is very difficult on traditional LPDAs.

Power is transferred through the coax cable, with an efficient, high power VSWR. Energy transfer is affected by the length of the cable run, which provides a certain amount of loss, both in terms of power and signal strength. The Arrow, like most LPDAs, runs on 50 ohm impedance. Its default connectors are N-Female, necessitating a coax with N-Male connectors to use with it.

Now, as has been pointed out, the main purpose of The Arrow is to improve cellular signal. There are very few cellular log periodic antennas on the market, and The Arrow is undeniably the most powerful of these.

Sources:

This article makes use of terms as defined in the United States Federal Standard 1037C.

Other Sources:
These sources can be found linked throughout the article.
Who wrote this article?
Who wrote this article?
Alex Baker
Senior Copywriter – Bolton Technical
Alex has been studying all things Signal Boosters for the past 5 years. He knows things and he likes to write about them. He’s also a best selling author of fiction novels and an avid video game player. He will take you to the mat with his WWE facts. He cooks a mean fried rice. He dislikes driving very much.
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