How Can I Increase My Transmission Range?

The distance you can communicate with your walkie-talkie is a function of signal strength, antenna gain, weather and atmospheric conditions, terrain, building materials, and other obstructions between the transmitter and receiver.

How can I increase my transmission range?:You can use several strategies:  

  • Increase power output (transmit)
  • Increase antenna height above a ground plane
  • Increase antenna gain (dBi)
  • Increase antenna height above a ground plane.

Click any of the tabs below to learn more. 

  • Increase Power Output (Transmit

  • Increase antenna height above a ground plane

  • Increase antenna gain (dBi)

  • Increase antenna height above a ground plane.

Increase Power Output (transmission)

In order to increase power output, you have to use a higher RF power transmitter, which incurs an additional cost.  You can increase the RF power output from your walkie-talkie by either using:

1) An external high powered directional antenna connected to your handheld transceiver and using it as an amplifier (repeater), or

2) Using a high-powered mobile transceiver (base station) to act as a repeater.

How does Signal Quality change as my transmission increases?

In terms of the signal-to-noise ratio (SNR), voice quality improves as transmission power increases.  

For example, if you talked with another party using 2 watts TX compared to 4 watts TX, there should be an audible difference in your point of view.  Most people would say that the audio is better when at a higher setting such as 5W or more.  

SNR will improve and voice quality will sound better.   Note that this is not true for the noise floor because it does not change based on how much transmission power you use!   

Why?

Because the noise level at the receiving end depends on many different factors including:

The amount of background noise/interference from other cell phones, radios, TV/radio stations, etc.  

The distance between you and the other party (longer distance results in weaker received signal strength because of path loss).  

BaoFeng bf-888s Antenna 10 X Original Antenna for Two Way Radio BaoFeng Bf-888s SMA Female, 400-470MHz

The characteristics of antennas:

There are a few characteristics of antennas;

Frequency, Wavelength, and Antenna Length

The frequency of a signal is a measurement of how many cycles (or changes) per second the wave makes.   A wavelength is a distance between two points on a wave that is direct across from each other when it passes through zero amplitude or its peak/trough point.

An antenna length is determined by measuring the full physical length of an antenna.


Resistance, Reactance, and Inductance

Resistance, reactance, and inductance are all forms of opposition to current flow in an AC circuit.


Power Factor and Phase Angle

These are two aspects related to power distribution along or within transmission lines.

Impedance Matching

Impedance matching is ensuring that the source and load impedance of an AC circuit are matched.   Matching sources and loads to each other will increase power transfer than if they are not matched.


For these four characteristics, you can specify the value as single or multiple values such as "75 ohms" or "50 ohms – 20MHz".  


These numerical specifications tell us what characteristic(s) of an antenna it is based on.


As for antennas used for cellular communications, you may see anyone (or a combination) of these numbers in commercial cellular antennas:


150, 7/8 wave (78/75 ) 300, 5/4 wave (79-70) 1206 2/5 wave (60-75)

These numbers express the following specifications about an antenna: frequency range, impedance, and antenna length.


For example, "150" means that this antenna is designed for frequencies between 145MHz-162MHz (1.5Ghz).   It has a 75-ohm impedance at 150MHz but changes to become 50 ohms by 1GHz.   The physical length of this 150 MHz antenna is 2 inches or 1206mm long which makes it a quarter-wave antenna.  


This same 2 inch long quarter-wave   (1206mm) antenna would be a half-wave in the 817MHz range due to its longer wavelength of 817/1206 = 0.65 meters which is also known as 600mm because 600mm = 1.18 feet and is used in the United States among other countries for antenna specifications.  


This means that each frequency range has its own standard physical size of antennas which gives us better control over design, performance, and manufacturing procedures such as testing to ensure high-quality results.


There are laws governing these requirements based on the usable bandwidths of various antenna frequencies at a given point.

To help illustrate the length of a wavelength, how far away from a cell tower antenna you would need to be to limit your radiation exposure to 1/10th of what it is at the FCC regulations limits:


While allowing such high levels of transmit power, cell towers are still limited to an output power of 27dBm (40 watts) into their antenna system which is shared by all phones within that location regardless of whether or not there is anyone calling on any given channel at the time.


To allow further increases in RF transmitting power over long distances along with additional performance improvements, wireless internet providers have adopted directional or high gain antennas mounted on towers or buildings to provide higher levels of data throughput in our wireless world.


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Antenna Gain

By using an antenna with more "gain" or power directive force, you can increase your transmission range and power.  

Gain is the measure of how much a particular directional antenna increases your RF signal strength by comparing it to the maximum radiation pattern for that type of antenna used on its own without any other antennas around it.   

 

For example, if a Yagi-Uda has 14dBi gain, then the difference between a 1-watt signal and 14 watts would be measured in time from point A to point B (known as Time Difference Of Arrival TDOA ) which allows us to calculate exactly how far away we have traveled from our starting location based upon this time difference.


Besides increasing transmit power output over longer distances through increased capabilities from using higher gain antennas such as Yagi-Uda or Moxon designs, it also helps prevent issues with multipath propagation where RF signals bounce off of objects in their way causing interference to other users on nearby channels.  


A directional antenna "rolls" your RF energy over the horizon which allows for a smooth signal output similar to how we hear things with our ears (related: decoding some of the secret sounds used by pilots and radar systems).


While there are many different types of antenna gain values listed, this is similar to speeding along in a car down a typical two-lane highway at an average speed of 55mph vs 60mph…


You won't notice much difference unless you hit someone from behind or have more cars around you!

Antenna Polarization

By using the correct type of antenna polarization, you will also greatly increase your range.   Polarization simply means that RF signals have two possible states which can be left-hand circular polarized (LHCP) or right-hand circular polarized (RHCP).


For example, if our radio were using LHCP and we wanted to talk over a long distance, then we would hypothetically want as many people around us operating on RHCP for best results as they are aligned with each other giving us the ability to send more information faster than if it was blocked by someone else on the same frequency using RHCP instead.  


This is often referred to as a cross-pol antenna.


In some cases using an omnidirectional antenna such as a Yagi-Uda will work better than a high gain directional antenna like a Moxon because it broadcasts in all directions regardless of polarization.  


If your radio is using RHCP and what you are communicating with is using LHCP, then this will allow for maximum communication performance.


Beyond obstructions, there are some general rules of thumb that will help you plan out your tower to optimize its performance via antenna gain and polarization requirements for the best range results:  


Distance Limitations - If in the case you are trying to communicate over a very long distance, then there may be some limitations that could come into play due to physics and your ability to maintain a high signal-to-noise ratio (SNR) once your RF signal reaches its maximum level.  


This can often depend on many factors including antenna gain and the frequency used by radios installed on different towers for example.   Another factor is that of our receiver antennas as these also have noise temperature limits just like in any radio system where data can get distorted or blocked altogether! 


For more information, please visit Understanding Noise Temperature & How It Relates To Wireless Communications.

Antenna Radiation Pattern

It can be reasonably extrapolated that the radiation pattern of a Moxon will look very similar.  


Therefore, typically when installing an omnidirectional antenna for GPS or television broadcasting, you would want to point it in as many directions as possible to increase its overall coverage area instead of focusing on only one direction.


High Gain Antenna - If you plan on using Wi-Fi gear which operates at high frequencies like 2.3GHz (802.11n) or 5GHz (802.11ac), then having a high gain antenna will be essential for good transmission range results and is what will allow for your signals to travel over long distances without getting blocked by obstructions such as mountains and buildings.


One of the key things to take into consideration is that these high frequencies are more readily blocked by objects so a good rule of thumb for getting around this limitation is to mount your antenna on top of a tower instead of labeling it an outdoor access point and putting it in the corner! 


Otherwise, modifications like adding reflectors or signal boosters can also help increase transmission range.


Limited Size - It should probably go without saying, but if you are installing a small low-gain antenna, then there is not much that can be done apart from tilting it in multiple directions and adding gain via other means such as high powered radios or reflectors.  

Antenna Gain is Key! - Having a good understanding of the relationship between antenna gain and range as well as the various ways to boost your transmission range power will help to increase how far your radio communications can travel within a given environment.


Also, check out this detailed page on Antenna Gain vs Distance.


Just keep in mind though that these charts tend to overestimate your results in many cases due to the amount of free space that does not exist when using wireless communications outdoors.


This creates a redundant wired and wireless network topology so even if some part of it fails, then you have multiple ways to get data back and forth from any given location on the network!

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How can I increase my transmission range? - Choosing the right antenna for your situation:

The right antenna for your situation is determined by a few considerations:

The receiver must be equipped with the right antenna system to get optimal reception quality

The receiver is operated in an indoor /outdoor location with short-distance reception

The receiver is operated in an indoor/outdoor location with long-distance reception:

Use the antenna divider for two or more receivers to simplify the antenna installation

Antenna systems for extremely long distances

A 16-channel wireless system antenna installation for long-distance reception