A donor antenna is tasked with receiving signals from a carrier radio tower, also known as the donor. Donor antennas are an important component of in-building radio enhancement systems. In fact, they are the MOST important antenna in the system. There are three components to in-building enhancement systems: the donor antenna, bi-directional amplifier, and distributed Antenna.

A donor antenna can be attached externally or internally, but in most cases, it is affixed to the roof of the building. It may also be affixed to the side of a building. For best results, there should be a clear path between the donor antenna and the closest communication tower.

Donor antennas create a two-way interface that brings signals in and out of a building. The downlink is the RF signal direction moving inside the structure, and the uplink is the RF signal as it is sent outside of the building.

BDA (Bi-Directional RF Amplifier)

Highly specialized RF amplifiers are tasked with picking which frequencies to amplify in downlink and uplink pathways. They also enhance RF signal strength moving in and out of the building. Technically known as “signal boosters,” they are regulated under strict federal guidelines that must be adhered by the system designer.

The RF Network

In most cases, non-radiating coaxial cables are used to route RF signals to indoor antennas set up to work with radios.

Radiating coaxial cables are designed to allow low level signals to sneak through the system. Radiating coaxial cables are often used for tunnels and passageways because RF signals lose their strength as they move through a coaxial cable, generally maxing out around 1,000 feet. 

Putting it all Together

A good example of these interconnected parts coming together is a roof top donor antenna that sits directly in sight of the distant radio tower it communicates with. From there, a coaxial cable connects the antenna to the BD RF amplifier, located several stories down inside of the building.

Omni-directional vs. Directional Antennas

Omni-directional antennas are the go-to option when multiple operator base stations require a donor signal. This type of antenna offers signal within a 360-degree radius, but gains are reduced and it cannot solve intercell-interference issues.    

Directional antennas offer greater signal strength and reduce interference. This type of antenna is tasked with drawing a donor signal to just one base station.

Type of donor antenna as well as installation methods will influence the quality of coverage a building receives.

Preventing Interference

A common in-building signal strength system issue is improper isolation or path loss from the roof antenna to the antennas inside of a building.  This issue causes system oscillates, which result in serious interference issues that may be considered illegal. You are not legally permitted to operate a signal booster that oscillates. Gain settings must be reduced to deter oscillations. The Federal Communications Commission (FCC) maintains the right to enforce fines and/or confiscate any equipment that is found to cause interference.

The standard formula for minimum antenna to antenna isolation is: BDA gain + 15 dB 

It’s important to note that additional gain does not equate to greater performance. It is recommended to use the minimum gain setting that proves reliable. Only a qualified radio technician should be tasked with adjusting the gain setting of the BDA.

Increase In-Building Signal Strength with Highland Wireless

Let Highland Wireless install an advanced Radio Enhancement System that meets Category 5 Hurricane-Rated bracketing, as well as R-56 Lightning Protection standards. We make it easy by taking care of everything from initial design to installation, and maintenance too. Learn more

Waterproof walkie-talkies offer a lot of convenience and reduce your risk for communication disasters. Certain job sites and events require waterproof radios due to heightened risk of water exposure.  Some radios are backed by greater moisture protection than others. To prevent confusion there’s an IP Code, or International Protection Rating, listed for each radio. This code number is used to define how much protection against water and solids a device is equipped with.

How to Read IP Ratings for Waterproof Walkie-Talkies

IP stands for Ingress Protection, or the level of protection provided by radio enclosures.  The first number after the letter P stands for “Solids Protection,” and the second digit stands for “Liquid Protection.” “Solids” include things like fingers, hands and dust. While “liquids” define moisture of many kinds. These standards are intended to provide more clarity than simply deeming every two-way radio waterproof. Otherwise, devices that can only withstand some water for short periods of time get lumped together with devices that can be submerged in water for 30 minutes or more.

Even electrical sockets get an IP rating. IP22 is the minimum requirement for interior electrical accessories. This number means outlets will not be damaged if someone tries to stick a finger inside, and they remain safe even if water drips over the outlet. Although, IP22 would be considered a low rating for two-way radios.

The most waterproof protection you can get is a number 8. While the most solid protection you can get is a 6. That means the highest level of protection against liquids and solids comes from a rating of IP68. This specific rating indicates a device is completely protected against dust ingress, as well as long term immersion up to a certain pressure.

Using the term “waterproof” suggests that no amount of water can damage a two-way radio. It’s important to note that electronics are more water resistant than waterproof. Just about any device will eventually incur damages if left submerged in water for too long or under too great of pressure.

3 Great Water Resistant Walkie-Talkies by Motorola & Kenwood

The Motorola XPR-7550

https://www.highlandwireless.com/portfolio/xpr-7550/

This rugged two-way radio offers just about everything you could ever want or need, starting with the fact it is Submersible (IP57). That means this device is protected against most dust and would have to encounter severe quantities to provoke issue. The second number represents liquid protection and a number 7 is the second to highest available level of water protection, offering immersion up to 1 m.

The Motorola SL 300

https://www.highlandwireless.com/portfolio/sl-300/#1499958900047-d13b59ed-73de6bca-26e3

This multi-purpose waterproof walkie-talkie offers a compact radio with a lot of power for an affordable price. This conveniently svelte two-way radio measures less than one-inch in thickness. It is rated IP54, making it slightly less tolerant to water than the Motorola XPR-7550, but just as hardy in terms of protection against solids.

The Kenwood NX-300 UHG NexEdge Radio

https://www.highlandwireless.com/portfolio/nx-300/#1499958900133-e6812103-0d0a

This Kenwood water resistant two-way radio has a nice screen, offers the option to add programmable features, and comes with substantial internal memory that can handle many frequencies and channels.

It is rated IP54/55, which means it can handle splashing water. It might survive a quick dip, but it’s not guaranteed to survive too much water exposure. Yet, for certain industries or purposes all you need is enough moisture protection for rain or some water splash-back.

The best walkie-talkie rental option may vary based upon the type and size of your event, as well as where it is located, inside or outside. We have a variety of Kenwood and Motorola walkie-talkie rentals to suit all your needs, regardless if you’re planning a large-scale concert, a big wedding, or outfitting security personnel at a shopping center.

Here are some important considerations to help you decide on the best radio for your event. Need additional help finding exactly what you need? Contact us today

1. Is the event scheduled to take place indoors or outdoors?

Indoor events require two-way radio signals capable of penetrating walls, and UHF radios are better at this than VHF radios. On the other hand, outdoor events are better suited by VHF radios because they offer optimal obstruction-free range. UHF is generally the best option if you need a walkie-talkie system that efficiently operates both inside and out.   

2. Do you need walkie-talkie rentals for long term or temporary use?

Do you need two-way radios that’ll keep going strong all day and night? Some two-way radios offer better battery life than others. While the average consumer radios offer around 8 hours of power, high-powered commercial radios can offer 12 or more hours of continuous battery life. Keeping the right accessories on hand, such as multi-unit charges, helps ensure there are always radios charged and ready to go.

3. How tough is the terrain?

How much wear and tear do radios need to withstand? For instance, the US military relies on rugged radios that can withstand extreme heat and water. You may or may not need waterproof, dustproof, or heat-proof walkie-talkies for your event, but we have them if you do!

Shop Motorola Two-Way Radios

4. Do you need Emergency Alert features?

An Emergency Alert feature is included with some radios. It allows users to press one button to send out a distress call to receiving radios. This alert may also prompt the device to become hands-free for a few seconds to allow the user to get a message across without touching anything by hand. This is an ideal feature for construction sites or other sites with potential dangers.

5. What kind of accessories do you need for two-way radios?

There are a wide range of two-way radio accessories available such as battery extenders, multi-unit chargers, as well as different headsets and earpieces. Hands-free features can be added via accessories; some radios come with built-in hands-free settings. This is convenient for employees tasked with juggling multiple tasks at once. 

Shop Kenwood Two-Way Radios

6. Do you need an On-Site Radio System?

On-site radios and network systems can be used to amplify signals clear across a campus or throughout a large building. On-Site Radio Systems by Highland Wireless facilitate seamless and sophisticated communication. We have many large-scale on-site installation projects under our belts, and are equipped to take care of everything from consulting to engineering, as well as installation and maintenance.  Learn more

7. Do you need Bluetooth or GPS?

Many of the best walkie-talkies for events come with advanced features like Bluetooth and GPS. Identify what you need to successfully operate your event. There’s no need to pay extra for these amenities if you don’t need them, but if you do, they can make all the difference.

Transmitters, receivers and antennas play important roles in the functionality of two-way radios, including base, mobiles and handheld radios. The radio is referred to as the transceiver, as it both sends and receives messages.

What is a Two-Way Radio Transmitter?

A transmitter is responsible for generating a radio signal or wave. The oscillator is a component of the transmitter tasked with generating frequency. Then, frequency multipliers go to work increasing frequency to final output. Power amplifiers are used to increase signal power so that adequate power output reaches the antenna.

The output frequency is called the carrier, or a continuous wave (CW). The frequency of the carrier can change based on the amplitude of the carrier or phase modulation. Amplitude (AM) and frequency modulation (FM) vary in several ways, but most notably FM modulation is less likely to encounter interference from RF noise.

What is a Two-Way Radio Receiver?

Think of the receiver as the transmitter’s polar opposite. The receiver is tasked with receiving the modulated carrier, processing it and sending it off to a detector station. From there, the modulation signal produced by the carrier is stripped off and original information is restored.

Most radio systems are designed to work with AM or FM. A microphone is used to input the information and a loud speaker is used to output the receiver. For the most part, signals are typically analog signals.

Binary signals are used to transmit data and at the simplest form this takes place using frequency shift keying (FSK). Most systems in place today rely on more complex schemes for transmitting data to maximize efficiency.

Most digital signals are virtually impossible for humans to unravel. That’s because we live in an analog world with audio frequencies. One exception is the use of Morse Code, which relies on a system of ones and zeros to transmit messages. If you are skilled at Morse Code, you know how to translate the dashes and dots so they equate to letters and numbers. When using digital radio, a digital-to-analog converter is essential to communicate with other humans.

Communication receivers almost always have “squelch circuits” that turn the output off when no signal is coming through. This prevents continuous noise from playing over the speaker. When a properly coded signal is detected, it allows it to pass through. Two common squelch schemes include continuous digital-coded squelch system (CDCSS) and continuous tone-coded squelch system (CTCSS).

What About Two-Way Radio Antennas?

The antenna plays an important role in the process, it takes the radio transmitter and sends it into space so that the receiver can pick up the energy. Lower frequency channels require a larger antenna for better communication. In most cases, the higher the antenna is from the ground, the greater the radio signal and overall coverage it offers.

A dipole is a crucial component of the antenna that includes a wire or rigid metal rod. The length of a dipole is based on ½ the wavelength of the carrier frequency. An example provided by the FCC states, “Thus, a 300 MHz carrier, with a wavelength of 1 meter, would need to use a dipole that is 1⁄2 meter long. Similarly, the dipole for a 900- MHz carrier, whose wavelength is 1/3 meter, would be 1/6 meter long.”

Antennas that sit vertical to the surface of earth give off vertical polarization. While antennas that sit horizontal to earth’s electric field are classified as horizontal polarization. Most mobile systems rely on vertical polarization.

The transmitter, receiver and antenna all play a vital role in the functionality of two-way radios. Without one, the whole system cannot operate properly.

Radio wave, wavelength, frequency—you’re sure to hear these terms tossed around when discussing two-way radios, but do you know what they mean? The following two-way radio terminology can help you better understand how two-way radios operate. After all, discussing two-way radios can start to feel like a lesson straight out of your college physics book. To simplify things, here’s an introduction to some of the basic terminology behind two-way radio systems.

1. Radio Wave

Radio communication is all about radio waves. Similar to ocean waves, radio waves flow up and down and can alter in how high they peak. But unlike ocean waves they are not visible to the human eye.

2. Wavelength

Radio waves are measured by the distance between one peak to the next—the space in between is known as the wavelength. A short wavelength relates to closely packed peaks, while long wavelengths are used to describe peak waves that are farther apart.

3. Cycle

Radio waves follow a specific pattern known as a ‘cycle.’ The pattern or cycle continues to repeat itself over and over.

4. Frequency

The number of cycles that occur every second is defined as the frequency. Radio engineers refer to “cycles per second” in “hertz,” or Hz for short. If someone says the wave frequency is 12 Hertz, that means there are 12 cycles occurring every second. Radio cycles generally repeat thousands of times each second. Engineers use kilohertz (KHz) to represent 1,000 cycles per second, and megahertz (MHz) to represent 1 million cycles per second. Additionally, gigahertz (GHz) translates to 1 billion cycles per second.

The higher the frequency the shorter the wavelength, and visa-versa. Interestingly, the wavelengths between super high frequencies (over 30 GHz) are so small that not even a single drop of water could fit in between the invisible peaks. Better coverage usually relates to lower frequency. VHF low band is credited with the most “effective radiated power” (ERP). 

Larger antennas are often required on lower frequency radios to improve communication.

5. Spectrum

Spectrum is used to define any range of frequencies that could potentially be used for radio communication purposes. Audible frequency range is typically somewhere between 20 and 18,00 cycles per second.

6. Bands

To make frequencies easier to comprehend, radio engineers group them into different categories or ranges, known as bands. Examples of bands include High Frequency (HF), Very High Frequency (VHF), Ultra-High Frequency (UHF), Superhigh Frequency (SF), Extremely High Frequency (EHF), and infrared.

7. Channels

The Federal Communications Commission (FCC) created their own categories to group frequencies, these are known as channels. The FCC is tasked with licensing out channels, and the specific center frequency or carrier frequency of that channel is identified. Radio communication is transmitted over multiple frequencies contained within one channel. The more frequencies contained within one channel, the larger its bandwidth and the more information it can transmit at one time.

The FCC provides an excellent example of this by comparing it to a highway. The wider a highway is, the more vehicles it can transmit at the same time. Think of larger bandwidth like a wider freeway—it can transmit more messages because it has a larger channel to work with. This is slowly changing though as technology advances; the latest microprocessors and software techniques require less bandwidth to transmit the same number of messages compared to 10-years ago. The FCC compares this concept to carpooling.

8. Building Penetration

UHF frequencies that have shorter wavelengths, generally in the 200 to 2,000 MHz range, provide better communication behind closed doors. That’s because they are better at penetrating building openings, like doors or windows, as opposed to VHF frequencies under 200 MHz. Low band VHF offers poor building penetration, while High Band VHF is slightly better.