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Hello world!

What’s the range for these to communicate with someone? How many miles?

This is almost the most common question people ask before getting a new two-way radio. But if you check the answers for the same radio, you may find many disapoointed people saying that only 0.5 mile, but also some saying 3 miles, 5 miles, and so on. Why they’re so diffenert?

Because the type of terrain and equipment can greatly affect the talking range. You often see ads for two-way radios saying “up to 36 miles” or more. Here the keyword in the advertisement are “up to”. This maximum range is more theoretical than realistic. So how far can you really expect to talk?

The key considerations that affect range are: signal type, antenna, obstructions, and signal strength (wattage). No single factor is a silver-bullet to extend your communication range. But taken in combination, they can mean the difference between getting 1/2 mile range, vs 6 miles or more. Let’s discuss each of these.

SIGNAL TYPE
First, not all radio signals are the same. They differ in how they travel, and how they react when they encounter materials.

Frequencies below 2MHz (Megahertz) are reflected off the atmosphere, thus they can follow the Earth’s curvature. So these low frequency signals can sometimes be received by radios below the horizon hundreds of miles away. As a general rule, the lower the frequency, the greater distance it can travel. CB radios, and some HAM frequencies, are in the HF (High Frequency) range of 29-54MHz, giving them some of these qualities. BUT, low frequencies are susceptible to some other issues.

VHF VS UHF WHICH IS BETTER?
The two frequency ranges (also called “frequency bands”) used in most two-way radios are VHF (Very High Frequency), and UHF (Ultra High Frequency). We are often asked “Is VHF or UHF better?” Neither is inherently better, they each have strong points and weaknesses.

VHF frequencies can penetrate objects better than UHF. VHF can also travel farther. If a VHF wave and a UHF wave were transmitted over an area without barriers, the VHF wave would travel almost twice as far. “Sign me up for VHF!” you say. Not so fast.

Even though VHF can pass through obstacles better and travel farther, that doesn’t mean it’s always the better choice. “Why?” you ask. It’s because of the difference between how VHF vs UHF signals react around structures. Remember, UHF signals are shorter than VHF, this is important when you’re in or around buildings.

To explain this let’s take an example. Assume you are trying to communicate from one side of a commercial building to the other. In between is a metal wall with a three foot opening. Radio waves cannot pass through metal. The UHF wavelength is roughly one and a half feet wide, the VHF wavelength is roughly five feet wide. The UHF signal (1 1/2 ft) passes through the door easily. However, the VHF signal is reflected since it is wider than the door. As you can see, UHF is better at navigating through the smaller spaces within a building to reach its destination. VHF signals are often blocked by metal within the building.

So to sum it up, it’s a trade off. But the general rule-of-thumb is if you are using the radio primarily outdoors where you will have clear line-of-sight then VHF is a better choice because its signal will travel farther. BUT, if you will be using your radio in or around buildings, in urban areas, or heavily wooded areas, then UHF is a better choice because its signal will navigate around structures better, not being blocked as easily as VHF. The trade-off you are making is longer distance (VHF), vs avoiding possible “dead spots” in and around structures (UHF).

ANTENNAS
One of the easiest ways to extend your range is by focusing on your antenna. When we said “the distance to the horizon is the maximum communication range” we didn’t mention one key factor, your antenna. The calculation of distances is based on the height of your antenna. In other words, the exact distance to the horizon varies depending on your antenna height. There is a formula for calculating distance to the horizon based on height.For now, let’s just leave it at a simple rule-of-thumb: a 6ft high antenna at both ends of the transmission (transmit & receive), will have a maximum range of approximately 6 miles.

So according to our rule-of-thumb, 2 people around 6 feet tall using a 5 watt handheld two-way radio, used on flat ground with no obstacles, will have a maximum range of approximately 6 miles. Are you guaranteed to get 6 miles? No. You may only get 4 miles or even less. What can you do to make it more like 6 miles than 4 miles? Use a better antenna!

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