The most obvious (and most frequent) question: “How far will I be able to reach with this radio?”. Honestly, there is no simple, straight-forward answer. The factors affecting the range of a two-way radio are: the radio’s antenna and power, and the terrain. Some insight on how each of these factors impacts your ability to transmit and receive over distance is below.
ANTENNAS
You know the higher you go, the greater the range. Having a tall antenna means having maximum range. Motorola two-way radios have removable antennas, so upgrading your antenna is a low-cost (around $20) easy way to improve range performance.
Mobile radio antennas are mounted on the outside of a vehicle, preferably on the roof, so the antenna as high as possible, providing maximum range.
POWER
Operating at maximum power will also help to improve range. Using fully charged batteries allows transmitting and receiving at the highest power level possible
The average li-ion battery contains 1.2V of power, and the average alkaline battery pack produces 1.5V. That makes battery packs worth looking into. Motorola IMPRES II batteries too. Having the right battery may mean the difference in getting the message out or not.
TERRAIN
Terrain has more affect than any other factor. Using a high perch, over flat terrain a two-way radio can transmit and receive up to 30 miles. On the ground with no obstacles to interfering, the curvature of the earth limits communications to about 6.5 miles. Adding obstructions such as trees, hills, valleys, and buildings may decrease a radio’s range to under a half mile.
Know your terrain before you buy. If you are needing radios for use in a fairly open area, then VHF model radios are best. The longer radio waves of a VHF radio give a greater range over open spaces. UHF is the best choice for use around structures and in dense areas.
IF THERE IS A NEED TO IMPROVE SYSTEM-WIDE RANGE: consider Motorola Two-Way Radio Repeaters or Bi-Directional Amplification (BDA).
A radio repeater is a combination of a radio receiver and a radio transmitter that receives a weak or low-level signal and retransmits it at a higher level or higher power. The result: two-way radio signals can cover longer distances without degradation. Repeaters are usually located on a mountain top, tall building, or radio tower. This allows communication between two or more bases, mobile or portable stations that are unable to communicate directly with each other due to distance or obstructions between them.
The repeater is synonymous with the base station, which performs both functions in most emergency dispatching systems.
The repeater receives on one radio frequency (the “input” frequency), demodulates the signal, and simultaneously re-transmits the information on its “output” frequency. All stations using the repeater transmit on the repeater’s input frequency and receive on its output frequency. The Motorola repeater product line-up provides a variety of choices, allowing you to tailor your solution to fit your needs and budget.
BDA’s are ideal for increasing range within buildings and down into basements. Concrete and metal strongly affect radio signals and limit range. Adding a BDA can amplify a radio’s transmit and receive strength and help get through those barriers.
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