UHF and VHF in the NZ Agricultural Context
Choosing the right frequency is the most important decision when designing a rural communication network. VHF (Very High Frequency) typically operates between 136 and 174 MHz, UHF (Ultra High Frequency) sits between 400 and 512 MHz. Selecting the wrong band can lead to permanent dead zones that no amount of extra battery power fixes.
Why Wavelength Matters to a Farmer
VHF waves are physically longer, which lets them bend or diffract over the top of rolling hills and follow the contours of the land. This makes VHF the go-to for large-scale dry stock stations with significant elevation changes, if you need to reach a shepherd on the other side of a ridge, VHF is generally your best bet.
UHF waves are shorter and travel in straighter lines. While they don't bend over hills as well, they excel at bouncing around solid objects and penetrating structures. If your operation involves dense housing, concrete yards, or thick shelterbelts, UHF often provides a more consistent link. Both frequencies rely on line-of-sight principles though, steep ridges will still create shadowing where signal is lost entirely.
PRS vs Commercial Frequencies
Many NZ farmers start with the Personal Radio Service (PRS), 80 designated UHF channels available for public use under a General User Radio Licence. PRS is cost-effective, but capped at 5 watts maximum power, a limit that often leaves farmers struggling for range across larger properties.
Moving to a private commercial frequency allows for much higher performance and privacy. Licensed systems, often featuring vehicle-mounted radios, can operate at up to 25 watts, giving significantly more punch through difficult terrain. Private channels also eliminate the chatter from neighbours or truckies that often plagues public PRS channels, and professional equipment must carry the RCM compliance mark to be legal in NZ.
How NZ Topography Affects Your Range
New Zealand's varied topography is the biggest hurdle for radio range. Dense vegetation and thick shelterbelts act as physical barriers, absorbing energy from the radio wave before it reaches its destination. Shadowing occurs when a steep ridge or deep gully sits between the transmitter and receiver, even a high-power radio can't always pass through solid earth.
For farms with extreme topographic challenges, a repeater station is often the only real solution. A repeater installed on a high point receives a signal and re-broadcasts it, effectively looking over the hills that block your line-of-sight.
VHF: The King of the Hill Country
Rugged sheep and beef stations almost always favour VHF. Its longer waves follow the ground's curve more effectively, requiring fewer repeater points to cover vast, rolling distances. The main trade-off is antenna size, VHF needs longer antennas, which need secure mounting on quads or side-by-sides to handle the vibration of hill work.
UHF: Precision for Flat Land and Infrastructure
Dairy farms and intensive horticulture blocks benefit from UHF's ability to bounce around buildings. Shorter UHF waves penetrate wintering barns and milking sheds more effectively than VHF, and UHF is generally more resilient against electrical noise from electric fences and heavy machinery, which can cause static on older analog VHF systems.
Matching Frequency to Farm Type
| Farm Type | Priority Frequency | Why |
|---|---|---|
| Hill country sheep and beef | VHF | Longer waves diffract over rolling terrain, fewer repeaters needed |
| Flat dairy and horticulture | UHF | Penetrates sheds and barns, resists electrical noise from fences and machinery |
| Multi-vehicle coordination | Vehicle-mounted 25W units | Acts as a backbone extending the reach of handheld users |
Many NZ properties feature a mix of river flats and steep back blocks. Relying on a single handheld frequency in these mixed environments often leads to communication gaps. A more reliable approach integrates handhelds with vehicle-mounted high-gain antennas, a ute parked on a high point can act as a localised hub, letting staff in the gullies stay in contact with the main shed.
The shift toward Digital Mobile Radio (DMR) has addressed many traditional interference issues too. Unlike analog radios that fade into static at the edge of range, DMR provides clear audio until the signal is completely lost, and DMR handhelds generally offer meaningfully longer battery life than older analog units since they only transmit half the time during a conversation, useful for long shifts during calving or mustering.
Commercial Licensing for NZ Farmers
Operating a commercial farm radio system requires more than buying a set of walkie-talkies off the shelf. The 80 public PRS channels are free to use under a General User Radio Licence but restricted to 5 watts, often not enough to cover an entire property.
Stepping up to a private, licensed frequency allows 25-watt vehicle-mounted units, a significant boost in range and reliability. As of 1 July 2026, the standard individual RSM licence fee is $190, with land mobile licences covering up to 5 repeater locations priced higher, and unlimited repeater locations higher again. Obtaining a licence involves an RSM Approved Radio Engineer conducting a site survey and engineering the frequency to avoid interference with existing users.
Getting the Right System in Place
Mobile Systems Limited is 100% New Zealand owned and based in Mount Maunganui, with over 25 years supplying and installing rural communication systems for NZ farms. Our mobile service vehicles travel directly to your property to tune and test every unit in the actual environment where it'll be used, and we manage the RSM licensing paperwork on your behalf.
