Why the Range on the Box Is a Myth
A big range figure on the packaging is a theoretical maximum. Think mountaintop to mountaintop across open water, with nothing in between.
The factor that governs real range is line of sight. Picture your antenna as a lighthouse: if a hill or building blocks the beam, the signal is blocked too.
Common obstructions in NZ
- Hills and dense bush can block signal entirely between two points.
- Concrete and steel absorb and reflect signal in towns and on building sites.
- Indoor barriers such as thick walls and metal shelving can cut contact between floors.
Plan for the ground you have, not the ground on the brochure.
The Four Factors That Determine Real Range
Terrain is fixed, so you work around it. The other three are within your control.
1. Power output
Doubling wattage does not double range. In open conditions you need roughly four times the power to double the distance, so a higher-wattage handheld helps less than most people expect. Vehicle-mounted radios run considerably more power than handhelds and usually carry better antennas, which is a genuine step up.
2. Frequency band
VHF's longer waves suit long, clear sightlines across farms, open country and water. UHF's shorter waves cope better with buildings, vehicles and clutter. Our UHF vs VHF guide covers which suits which environment.
3. The antenna
The standard stubby antenna on most handhelds trades performance for portability. Height gets your signal over obstructions, and gain focuses it, like a torch beam compared with a bare bulb.
4. Terrain
A single ridge between two users can block contact completely, whatever the radio. That is why coverage design starts with the map, not the spec sheet.
How Far Your Radio Can Physically See
Even on perfectly flat ground, the curve of the earth sets a hard limit. A common rule of thumb for the distance to the horizon is roughly 3.57 multiplied by the square root of the antenna height in metres, giving the answer in kilometres.
| Antenna height | Distance to horizon (flat ground) | Typical example |
|---|---|---|
| 1.5 m | About 4.4 km | Handheld at head height |
| 2 m | About 5 km | Roof of a ute |
| 10 m | About 11 km | Mast on a building |
| 20 m | About 16 km | Repeater mast on high ground |
Two radios can each "see" their own horizon, so on truly flat, open ground two handhelds could in theory reach a little under 9 km. Add hills, bush or buildings and it drops sharply, which is why height matters so much.
Every metre of height you add buys range that no extra wattage can match.
How to Extend Your Range
Simple upgrades
- Upgrade the antenna. A better-matched whip is usually the best value improvement. Our UHF antenna guide covers gain and mounting.
- Get higher. Higher ground, an upper-floor window or the tray of a ute can clear an obstruction entirely.
- Move away from clutter. Stepping clear of vehicles, sheds and walls often restores a weak signal.
Vehicle-mounted radios
A vehicle radio with an external roof antenna runs more power and sits higher than any handheld. For forestry crews, transport operators and farm managers, the vehicle effectively becomes a mobile base station.
Repeaters and system design
For consistent coverage across a full site, valley or large farm, a repeater at a high point receives weak signals and rebroadcasts them at higher power. See simplex vs repeater channels and what a digital repeater does.
When radio cannot reach
If your team is spread across regions, PoC radios use the cellular network instead of line of sight.
Start with the cheapest fix that clears the obstruction, and only then spend on bigger hardware.
Getting the Right System in Place
Mobile Systems Limited is 100% NZ-owned and based in Mount Maunganui, with over 25 years designing radio systems for NZ terrain. As a brand-independent supplier, we recommend what covers your ground, not a single manufacturer's range.
We supply equipment nationwide, with on-site installation and service across the Bay of Plenty, Coromandel, Rotorua, Taupō, South Waikato, Volcanic Plateau and Eastern Waikato.
