Have you ever shouted in a concrete wall? Basically, that is what your phone does when you find yourself in a modern building with thick walls. I would like to explain why routine communication in concrete structures is about as successful as a date with Mother Teresa and more to the point; how to remedy it.
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The Reasons Concrete Buildings Are Communication Nightmare
This is the thing about concrete: It is great stuff when it comes to the strength of the structure but it is lousy when it comes to radio signals . That lovely concrete wall that saves you against weather? It also is obstructing up to 82 percent of the radiations attempting to reach you.
Consider radio waves as water which attempts to pass through various materials. Wood? Easy passage. Glass? Minor resistance. Yet concrete reinforcement with steel? It is like trying to force water through a brick, most of it bounces off .
Height in building as well as density is increasing the problem. The current buildings have steel-enhanced concrete, which forms what engineers term as a Faraday cage effect – which basically makes your building a signal blocker in itself . Concrete walled buildings may lead to the loss of 10-15dB through a single wall so attempting to get through several walls may result in a loss of 70% of the signal strength .
UHF versus VHF The Debate of Frequencies: Which is the Winner?
here is something interesting: The majority of the population believes that the higher the frequency, the better the performance but this is not exactly the case with the concrete buildings.
UHF radios (Ultra High Frequency) are in 400-470MHz and namely have shorter wavelengths that actually penetrate better through the concrete and steel as opposed to its counterpart- VHF. Consider the UHF waves as smaller, nimbler, they can fit through small slots and around objects that would parallelize bigger waves .
VHF radios ( Very High Frequency ) operate between 136-174 MHz, and are generally more effective in cases where there are open fields but fail immensely when it comes to concrete . But here is the catch-VHF may sometimes penetrate thick concrete walls better than UHF does especially in the extremely thick walls.
What does professional opinion hold? UHF prevails amongst building applications that are most concrete . UHF frequencies find it easier to penetrate walls, steel as well as concrete and thus are ideal to use indoors .
Digital vs. Analog: The new Vs. Old School?
Now here is where it gets really interesting. Whereas analog radios have been the workhorses of communication over the last decades, digital technology is transforming the way we communicate in adverse environment .
The audio crystallinity of digital radios is exceptionally high all the way to the fringe of the coverage range–gone is the old static-filled speech as you move out of range of the transmitter . They also provide higher battery life and tend to have 40 percent more operation than analog options .
Analog radios are not gone yet and the demand is still valid with simple communication requirements and cash-conscious customers. They are easy, in most cases cheaper and every technician knows how to handle them.
But honestly? When you want to work on concrete buildings, do not go the traditional way, go digital. Digital radios stand a higher likelihood of sustaining the communications in a hostile terrain such as concrete structures .
We have the Best Choices of Concrete Building Communication
In cases of Small to Medium Buildings: Motorola RMU2080
The motorola rmU2080 is the swiss army knife in the business radio world. This radio has a power of 2 watts of UHF that is able to cover an area of 250,000 square feet or 20 floors. The presence of the antimicrobial coating is a very good addition- this in this current health conscious environment.
Key Features:
- 8 channels and 99 business UHF frequencies
- 219 privacy codes to reduce interferences
- Military durable strength
- IP54 water and dust proof
In the case of Heavy-Duty Uses: DEWALT DXFRS800
There are times when you will require a super strong radio that is as tough as the place of work. DEWALT DXFRS800 offers the construction grade durability, with IP67 rating, i.e. it is dust-proof and it can survive up to 1 meter under water.
Standout Features:
- 2-watt power with a range of 300,000 sq. ft.
- 22 built-in channels and 121 privacy codes
- Up to two meters drop resistant
- Amazing 18 hour battery life
In the case of Digital Excellence: Motorola MOTOTRBO series
The MOTOTRBO is the state of the art in digital radio . These are not ordinary radios; they actually talk; not only that but also have the feature of the GPS tracking and messaging capabilities, not forgetting that they could be connected to Wi-Fi and LTE networks .
MOTOTRBO Ion Rugged Commercial Smart Radio is remarkable when it comes to concrete building use. It is inherently safe and therefore would not occasion sparks in hazardous areas and it has what is referred to as remastered digital technology which also factors in adaptation to various types of communication platforms automatically.
The Affordable alternative Kenwood NX-340U16P
At new work sites that do not have radio facilities in place, the Kenwood NX-340U16P radio will deliver 5 watts of UHF digital power with superb sound . The coverage charts of Kenwood indicate that yet this radio is able to transmit in a concrete building up to 42 floors when 5-watt UHF energy is used.
Power Matters: What No one ever told you about Wattage in a concrete building
Some confusion has existed in regard to power ratings. The higher the watts, the better your range will be, but it is not that easy .
- 2-Watt Radios: These are best suited where the building is smaller and the building height is up to 23-28 stories or the building doesn t have much iron in it
- 5-Watt Radios: The magic figure spread in most concrete-based application with a coverage of 42-50 floors
- 8-Watt Options: In situation of extreme conditions when the maximum penetration is required
The average construction site would require 4-5 watts to ensure good communication with buildings that are vertical . The cheap FRS radios may be suitable when you are still doing early stages of construction but as soon as the concrete begins going up you will be sorry since you chose the cheap models.
When Straight Forward Radios Won?t Do: Signal Amplifiers and Repeaters
Even the most famous handheld radios reach their boundaries at times. That is where the enhancement systems of building come in.
The Bi-Directional Amplifiers (BDAs) intercept the input signals, boost them and transfer the enhanced signals to the rest of your building . Conceive them like the megaphones of radio signals as they receive softly and convey the signals to reach your concrete castle in a strong manner .
The Distributed Antenna Systems (DAS) helps in association with BDAs to create an even distribution of signals within a structure. Such systems have many antennas that are linked to each other using cables such that the coverage is available in the most corners including the difficult to reach locations such as the basement and the stairwell.
Here is what is important, you will be required to upgrade to 700MHz to accommodate modern P25 digital systems in case you are currently operating in legacy 800MHz. This is a step that most facilities have already adapted in order to keep up with the changing communication standards.
Licensing The Wrong No one Talks About
This is one of the things that you might not know, most of the business grade UHF and VHF radios require an FCC license . The positive thing is? But this is not as complex as it may sound.
The license fee of a single frequency business radio is about 170 and is good up to 10 years. The license allows no other business in your locality to use the same frequencies and a resultant interference problem is avoided.
You will be able to apply yourself with the help of FCC Forms 160 and 601, yet, to be honest, you will be able to. The majority of professionals suggest to hire a frequency coordinator to work out the paperwork and make sure you are assigned with the correct frequencies peculiar to your location.
Real Performance in Real-World: Expectations
Let me keep realistic expectations here. Not even the best radio will make concrete into glass . Exploratory research indicates that concrete thickness of 200mm is capable of absorbing up to 82% radio signals with frequencies of 400 MHz.
But things are not that good, moisture will aggravate the situation even more one study showed that wet concrete can result in another 6-12 dB signal degradation . That is why weatherproofing does not only mean to as sure the radio about incoming rain but to keep your performance and functions steady when the building materials jump into another electronic electric state.
Tips to Installation That Work
Antenna Placement: Ensure that you put your antennas in the highest places as much as possible and not near concrete masses. A slight distance can provide the dramatic difference in signal propagation even in few feet.
Phase Shifters: The passive repeater system can perform better by adjusting phases, up to 15-17 dB, adjacent to a repeater .
Coverage Mapping: Your system should be tested before it is completed. Something that appears on paper may not be feasible in your building arrangement.
What the Future of Building Communication Persists to Be
The communication environment continues to change. We are already witnessing Push-to-Talk over Cellular (PoC) radios with LTE infrastructure nationwide coverage . In really tough conditions, more and more hybrid systems using both conventional radio together with Wi-Fi and cellular networks are coming to the fore .
There are now high end radios that have many forms of communication on one radio; old fashioned two-way radio, Wi-Fi, LTE and even super fast video . It is as close as totally being able to carry around a complete communication center.
Coming Up with Your Decision
Selecting the suitable radio system in concrete buildings boils down to the appreciation of your unique requirements. Small retail jobs may be able to use 2-watts UHF, though a 5-watt digital system with repeater support is required on high-rise construction jobs.
And don not forget about accessories. Quality chargers, earpieces and carrying cases can spell the difference between explaining system efficiency or failure of your communication system. It is pointless to have a radio that gives out during the shift, or when a staff drops it.
It is known that radio will be a problem behind concrete buildings, but that is the basic science . However, when you have the right equipment in place along with proper installation and live up to reality, you are able to keep open and dependable communication even with the most difficult situations.
Your secret formula is to select a radio type that best fits the particular building, know its limitations and buy a quality product that will wear well. Since at the time you truly need to contact someone nothing will be more important as a proper radio be it to arrange a construction project or to provide someone with safety in the case of emergency.
