One of the most common questions we get asked is, “how far will I be able to transmit and receive with this radio?” Unfortunately, there is no simple answer to that question. There are many factors that affect the range of two-way radio: terrain, environment, the radio’s power, and even the antenna. Today, we will discuss some of these factors and the best tips for combating them to get you a better range for your two-way investment.
The greatest factor that affects range is the terrain that the radio will be used in. In a perfect scenario, a two-way radio can transmit and receive up to 30 miles...but that is from an extremely elevated surface with completely flat terrain below. Even from standing on the ground with no obstacles to interfere with the signal, the curvature of the earth cuts off the straight-lined radio waves at 6.5 miles. So, when trees, hills, valleys, and buildings are thrown into the mix, it’s easy to see how a radio’s range can drop to under a half-mile.
The best way to ensure you’re getting a maximum range is to know your terrain before you buy. If you are needing radios for use in a fairly open area, then a VHF model radio is best for you. The longer radio waves of a VHF radio give a greater range over open spaces, but they can not penetrate through obstacles as well as the shorter, faster waves of a UHF radio. That makes UHF the best choice for use around structures and in dense areas.
When it comes to range, the higher up you go, the further your signal travels, so having a tall antenna, means your radio is set up for maximum range. Ideally, you want a radio with at least a 6” whip antenna, which has an average price of around $20. Most modern two-way radios have removable antennas, so upgrading your antenna is a low-cost, easy way to improve range performance.
If you are a mobile (vehicle) radio user, be sure your antenna is mounted on the outside of your vehicle, preferably on the roof, so you can get the antenna as high as possible.
Having maximum radio power will also help to improve range and coverage. Fully charging your batteries before radio use means you are transmitting and receiving with as much power and strength as possible.
If your full battery is not quite giving enough power to reach the edges of your talk zones, you may want to look at trying out an alkaline battery pack. The average li-ion battery contains 1.2V of power, whereas an alkaline battery pack with disposable AA batteries will put out 1.5V. That may mean the difference in getting the message out or not.
Just out of range?
When you are on the edge of your range, and you are struggling to communicate to other radios, there are a few tricks that you can use to increase your range just enough to hear or talk when you need it.
First off, Climb. Get to the highest point you can so your radio will have a greater line of sight.
Second, Stand Up. Most people don’t think doing something so simple would yield dramatically different results, but the simple act of standing can increase your range over 1 mile!
Third, Use High Power Mode. Initiating High Power Mode will give a significant boost to your signal which improves your coverage and can give a boost to your range in dense areas.
If all else fails, try the Monitor Function. Turning on Monitor will open your radio up to all signals on your frequency and will boost its receiving power. You will hear all the static and sounds occurring on your frequency, which can mean the difference between hearing an important message, and hearing nothing.
Building up your system?
If you are in need of some serious range upgrades, you may need to look towards Motorola Two-Way Radio Repeater options, like the new Motorola SLR 5700 or Bi-Directional Amplification (BDA).
A repeater will pick up weakened radio signals and repeat them back out with a boost of power, giving you up to twice the range your two-way radio would normally be able to achieve. Repeaters are great for large outdoor areas that have many hills and valleys that would normally cut the radio signal short. They are also typically installed with a large antenna in the highest area possible to get the maximum line-of-sight and range.
BDA’s are ideal for increasing range within buildings and down into basements. Concrete and metal do serious damage to radio signals and limit range severely, but adding a BDA can amplify your transmit and receive strength and help get through those barriers.
If you are wanting to learn more about improving your range through repeater systems or BDA’s, contact us today. We are glad to assist you in getting the range you need to drive your business forward. Also, learn more about two-way radio technology by downloading and reading our free eBook, "Two-Way Radios: The Leading Technology for Critical Communications".